Network Working Group J. Loughney, Ed.
Request for Comments: 3868 Nokia
Category: Standards Track G. Sidebottom
Signatus Technologies
L. Coene
G. Verwimp
Siemens n.v.
J. Keller
Tekelec
B. Bidulock
OpenSS7 Corporation
October 2004
Signalling Connection Control Part User Adaptation Layer (SUA)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004).
Abstract
This document defines a protocol for the transport of any Signalling
Connection Control Part-User signalling over IP using the Stream
Control Transmission Protocol. The protocol is designed to be
modular and symmetric, to allow it to work in diverse architectures,
such as a Signalling Gateway to IP Signalling Endpoint architecture
as well as a peer-to-peer IP Signalling Endpoint architecture.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope. . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Abbreviations and Terminology. . . . . . . . . . . . . . 4
1.3. Signalling Transport Architecture. . . . . . . . . . . . 6
1.4. Services Provided by the SUA Layer . . . . . . . . . . . 9
1.5. Internal Functions Provided in the SUA Layer . . . . . . 11
1.6. Definition of SUA Boundaries . . . . . . . . . . . . . . 14
2. Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . 19
3. Protocol Elements. . . . . . . . . . . . . . . . . . . . . . . 19
3.1. Common Message Header. . . . . . . . . . . . . . . . . . 20
3.2. SUA Connectionless Messages. . . . . . . . . . . . . . . 24
3.3. Connection Oriented Messages . . . . . . . . . . . . . . 27
3.4. Signalling Network Management (SNM) Messages . . . . . . 42
3.5. Application Server Process State Maintenance Messages. . 49
3.6. ASP Traffic Maintenance Messages . . . . . . . . . . . . 53
3.7. SUA Management Messages. . . . . . . . . . . . . . . . . 56
3.8. Routing Key Management (RKM) Messages. . . . . . . . . . 58
3.9. Common Parameters. . . . . . . . . . . . . . . . . . . . 61
3.10. SUA-Specific parameters. . . . . . . . . . . . . . . . . 74
4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . 92
4.1. Procedures to Support the SUA-User Layer . . . . . . . . 92
4.2. Receipt of Primitives from the Layer Management. . . . . 93
4.3. AS and ASP State Maintenance . . . . . . . . . . . . . . 95
4.4. Routing Key Management Procedures. . . . . . . . . . . .109
4.5. Availability and/or Congestion Status of SS7
Destination Support101 . . . . . . . . . . . . . . . . .112
4.6. MTP3 Restart . . . . . . . . . . . . . . . . . . . . . .115
4.7. SCCP - SUA Interworking at the SG. . . . . . . . . . . .115
5. Examples of SUA Procedures . . . . . . . . . . . . . . . . . .117
5.1. SG Architecture. . . . . . . . . . . . . . . . . . . . .117
5.2 IPSP Examples. . . . . . . . . . . . . . . . . . . . . .119
6. Security Considerations. . . . . . . . . . . . . . . . . . . .121
7. IANA Considerations. . . . . . . . . . . . . . . . . . . . . .121
7.1. SCTP Payload Protocol ID . . . . . . . . . . . . . . . .121
7.2. Port Number. . . . . . . . . . . . . . . . . . . . . . .121
7.3. Protocol Extensions. . . . . . . . . . . . . . . . . . .121
8. Timer Values . . . . . . . . . . . . . . . . . . . . . . . . .123
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .123
10. References . . . . . . . . . . . . . . . . . . . . . . . . . .123
10.1. Normative References . . . . . . . . . . . . . . . . . .123
10.2. Informative References . . . . . . . . . . . . . . . . .124
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Appendix A. Signalling Network Architecture . . . . . . . . . . .125
A.1. Generalized Peer-to-Peer Network Architecture. . . . . .125
A.2. Signalling Gateway Network Architecture. . . . . . . . .126
A.3. Signalling Gateway Message Distribution
Recommendations. . . . . . . . . . . . . . . . . . . . .128
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .129
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . .131
1. Introduction
There is ongoing integration of switched circuit networks and IP
networks. Network service providers are designing IP-based
signalling architectures that need support for SS7 and SS7-like
signalling protocols. IP provides an effective way to transport user
data and for operators to expand their networks and build new
services. In these networks, there is need for interworking between
the SS7 and IP domains [2719].
This document defines a protocol for the transport SS7 SCCP-User
protocols [ANSI SCCP] [ITU SCCP], such as TCAP and RANAP, over IP
using the Stream Control Transmission Protocol (SCTP) [2960].
1.1. Scope
This document details the delivery of SCCP-user messages (MAP & CAP
over TCAP [ANSI TCAP] [ITU TCAP], RANAP [RANAP], etc.) messages over
IP between two signalling endpoints. Consideration is given for the
transport from a signalling gateway to an IP signalling node (such as
an IP-resident Database) as described in the Framework Architecture
for Signalling Transport [2719]. This protocol can also support
transport of SCCP-user messages between two endpoints wholly
contained within an IP network.
The delivery mechanism addresses the following criteria:
* Support for transfer of SCCP-User Part messages
* Support for SCCP connectionless service.
* Support for SCCP connection oriented service.
* Support for the operation of SCCP-User protocol peers.
* Support for the management of SCTP transport associations between
signalling gateways and IP-based signalling nodes.
* Support for distributed IP-based signalling nodes.
* Support for the asynchronous reporting of status changes to
management functions.
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1.2. Abbreviations and Terminology
1.2.1. Abbreviations
CAP - CAMEL Application Protocol.
GTT - Global Title Translation.
MAP - Mobile Application Protocol.
PC - Signalling System no. 7 Point Code.
RANAP - Radio Access Network Application Protocol.
SCTP - Stream Control Transmission Protocol.
SS7 - Signalling System no. 7.
TCAP - Transaction Capabilities Application Protocol.
1.2.2. Terminology
Signalling Gateway (SG) - Network element that terminates switched
circuit networks and transports SCCP-User signalling over IP to an IP
signalling endpoint. A Signalling Gateway could be modeled as one or
more Signalling Gateway Processes, which are located at the border of
the SS7 and IP networks. Where an SG contains more than one SGP, the
SG is a logical entity and the contained SGPs are assumed to be
coordinated into a single management view to the SS7 network and to
the supported Application Servers.
Application Server (AS) - A logical entity serving a specific Routing
Key. An example of an Application Server is a virtual IP database
element handling all requests for an SCCP-user. The AS contains a
set of one or more unique Application Server Processes, of which one
or more is normally actively processing traffic.
Application Server Process (ASP) - An Application Server Process
serves as an active or backup process of an Application Server (e.g.,
part of a distributed signalling node or database element). Examples
of ASPs are MGCs, IP SCPs, or IP-based HLRs. An ASP contains an SCTP
endpoint and may be configured to process traffic within more than
one Application Server.
IP Server Process (IPSP) - A process instance of an IP-based
application. An IPSP is essentially the same as an ASP, except that
it uses SUA in a peer-to-peer fashion. Conceptually, an IPSP does
not use the services of a Signalling Gateway.
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Signalling Gateway Process (SGP) - A process instance of a Signalling
Gateway. It serves as an active, load-sharing or broadcast process
of a Signalling Gateway.
Signalling Process - A process instance that uses SUA to communicate
with other signalling process. An ASP, a SGP and an IPSP are all
signalling processes.
Association - An association refers to an SCTP association. The
association provides the transport for the delivery of SCCP-User
protocol data units and SUA layer peer messages.
Routing Key - The Routing Key describes a set of SS7 parameters
and/or parameter ranges that uniquely defines the range of signalling
traffic configured to be handled by a particular Application Server.
An example would be where a Routing Key consists of a particular SS7
SCCP SSN plus an identifier to uniquely mark the network that the SSN
belongs to, for which all traffic would be directed to a particular
Application Server. Routing Keys are mutually exclusive in the sense
that a received SS7 signalling message cannot be directed to more
than one Routing Key. Routing Keys can be provisioned, for example,
by a MIB or registered using SUA's dynamic registration procedures.
Routing keys MUST NOT span multiple network appearances.
Routing Context - An Application Server Process may be configured to
process traffic within more than one Application Server. In this
case, the Routing Context parameter is exchanged between the SGP and
the ASP (or between two ASPs), identifying the relevant Application
Server. From the perspective of an SGP/ASP, the Routing Context
uniquely identifies the range of traffic associated with a particular
Application Server, which the ASP is configured to receive. There is
a 1:1 relationship between a Routing Context value and a Routing Key
within an AS. Therefore the Routing Context can be viewed as an
index into an AS Table containing the AS Routing Keys.
Address Mapping Function (AMF) - The AMF is an implementation
dependent function that is responsible for resolving the address
presented in the incoming SCCP/SUA message to correct SCTP
association for the desired endpoint. The AMF MAY use routing
context / routing key information as selection criteria for the
appropriate SCTP association.
Fail-over - The capability to reroute signalling traffic as required
to an alternate Application Server Process, or group of ASPs, within
an Application Server in the event of failure or unavailability of a
currently used Application Server Process. Fail-over may apply upon
the return to service of a previously unavailable Application Server
Process.
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Host - The computing platform that the SGP or ASP process is running
on.
Layer Management - Layer Management is a nodal function that handles
the inputs and outputs between the SUA layer and a local management
entity.
Network Appearance - The Network Appearance is an SUA local reference
(typically an integer) shared by SG and AS that together with a
Signalling Point Code uniquely identifies an SS7 node by indicating
the specific SS7 network it belongs to.
Network Byte Order - Most significant byte first, a.k.a. Big Endian.
Stream - A stream refers to an SCTP stream; a unidirectional logical
channel established from one SCTP endpoint to another associated SCTP
endpoint, within which all user messages are delivered sequenced
except for those submitted to the unordered delivery service.
Transport address - an address that serves as a source or destination
for the unreliable packet transport service used by SCTP. In IP
networks, a transport address is defined by the combination of an IP
address and an SCTP port number. Note, only one SCTP port may be
defined for each endpoint, but each SCTP endpoint may have multiple
IP addresses.
1.3. Signalling Transport Architecture
The framework architecture that has been defined for switched circuit
networks signalling transport over IP [2719] uses multiple
components, including an IP transport protocol, a signalling common
transport protocol and an adaptation module to support the services
expected by a particular switched circuit networks signalling
protocol from its underlying protocol layer.
In general terms, the SUA architecture can be modeled as a peer-to-
peer architecture. The first section considers the SS7 to IP
interworking architectures for connectionless and connection-oriented
transport. For this case, it is assumed that the ASP initiates the
establishment of the SCTP association with SG.
1.3.1. Protocol Architecture for Connectionless Transport
In this architecture, the SCCP and SUA layers interface in the SG.
Interworking between the SCCP and SUA layers is needed to provide for
the transfer of the user messages as well as the management messages.
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******** SS7 *************** IP ********
* SEP *---------* *--------* *
* or * * SG * * ASP *
* STP * * * * *
******** *************** ********
+------+ +------+
| SUAP | | SUAP |
+------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+
| MTP3 | | MTP3 | | | |
+------+ +------+ SCTP | | SCTP |
| MTP2 | | MTP2 | | | |
+------+ +------+------+ +------+
| L1 | | L1 | IP | | IP |
+------+ +------+------+ +------+
| | | |
+---------------+ +------------+
SUAP - SCCP/SUA User Protocol (TCAP, for example)
STP - SS7 Signalling Transfer Point
See Appendix A.3.1 for operation recommendations.
1.3.1.1. SG as endpoint
In this case, the connectionless SCCP messages are routed on point
code (PC) and subsystem number (SSN). The subsystem identified by
SSN and Routing Context is regarded as local to the SG. This means
from SS7 point of view, the SCCP-user is located at the SG.
1.3.1.2. Signalling Gateway as relay-point
A Global Title translation is executed at the signalling gateway,
before the destination of the message can be determined. The actual
location of the SCCP-user is irrelevant to the SS7 network. GT
Translation yields an "SCCP entity set", from which an Application
Server can be derived. Selection of the Application Server is based
on the SCCP called party address (and possibly other SS7 parameters
depending on the implementation).
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1.3.2. Protocol Architecture for Connection-Oriented Transport
In this architecture, the SCCP and SUA layers share an interface in
the signalling gateway process to associate the two connection
sections needed for the connection-oriented data transfer between SEP
and ASP. Both connection sections are setup when routing the Connect
Request messages from the signalling end point via signalling gateway
process to ASP and visa versa. The routing of the Connect Request
message is performed in the same way as described in 1.3.1.
******** SS7 *************** IP ********
* SEP/ *---------* SG *--------* ASP *
* STP * * * * *
******** *************** ********
+------+ +------+
| SUAP | | SUAP |
+------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+
| MTP3 | | MTP3 | | | |
+------| +------+ SCTP | | SCTP |
| MTP2 | | MTP2 | | | |
+------+ +------+------+ +------+
| L1 | | L1 | IP | | IP |
+------+ +------+------+ +------+
| | | |
+---------------+ +------------+
SUAP - SCCP/SUA Application Protocol (e.g., - RANAP/RNSAP)
STP - SS7 Signalling Transfer Point
See Appendix A.3.2 for operation recommendations.
1.3.3. All IP Architecture
This architecture can be used to carry a protocol that uses the
transport services of SCCP within an IP network. This allows
flexibility in developing networks, especially when interaction
between legacy signalling is not needed. The architecture removes
the need for signalling gateway functionality.
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******** IP ********
* IPSP *--------* IPSP *
******** ********
+------+ +------+
| SUAP | | SUAP |
+------+ +------+
| SUA | | SUA |
+------+ +------+
| SCTP | | SCTP |
+------+ +------+
| IP | | IP |
+------+ +------+
| |
+----------------+
SUAP - SCCP/SUA Application Protocol (e.g., - RANAP/RNSAP)
1.3.4. ASP Fail-over Model and Terminology
The SUA protocol supports ASP fail-over functions to support a high
availability of transaction processing capability.
An Application Server can be considered as a list of all ASPs
configured/registered to handle SCCP-user messages within a certain
range of routing information, known as a Routing Key. One or more
ASPs in the list may normally be active to handle traffic, while
others may be inactive but available in the event of failure or
unavailability of the active ASP(s).
For operation recommendations, see Appendix A.
1.4. Services Provided by the SUA Layer
1.4.1. Support for the transport of SCCP-User Messages
The SUA supports the transfer of SCCP-user messages. The SUA layer
at the signalling gateway and at the ASP support the seamless
transport of user messages between the signalling gateway and the
ASP.
1.4.2. SCCP Protocol Class Support
Depending upon the SCCP-users supported, the SUA supports the 4
possible SCCP protocol classes transparently. The SCCP protocol
classes are defined as follows:
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* Protocol class 0 provides unordered transfer of SCCP-user messages
in a connectionless manner.
* Protocol class 1 allows the SCCP-user to select the sequenced
delivery of SCCP-user messages in a connectionless manner.
* Protocol class 2 allows the bidirectional transfer of SCCP-user
messages by setting up a temporary or permanent signalling
connection.
* Protocol class 3 allows the features of protocol class 2 with the
inclusion of flow control. Detection of message loss or mis-
sequencing is included.
Protocol classes 0 and 1 make up the SCCP connectionless service.
Protocol classes 2 and 3 make up the SCCP connection-oriented
service.
1.4.3. Native Management Functions
The SUA layer provides the capability to indicate errors associated
with the SUA-protocol messages and to provide notification to local
management and the remote peer as is necessary.
1.4.4. Interworking with SCCP Network Management Functions
SUA uses the existing ASP management messages for ASP status
handling. The interworking with SCCP management messages consists of
DUNA, DAVA, DAUD, DRST, DUPU or SCON messages (defined in section 3)
on receipt of SSP, SSA, SST or SSC (defined by SCCP) to the
appropriate ASPs. See also chapter 1.4.5. The primitives below are
sent between the SCCP and SUA management functions in the SG to
trigger events in the IP and SS7 domain.
Generic |Specific |
Name |Name |ANSI/ITU Reference
----------+-----------+---------------------------------------------
N-State |Request |ITU-Q.711 Chap 6.3.2.3.2 (Tab 16/Q.711)
|Indication |ANSI-T1.112 Chap 2.3.2.3.2 (Tab 8E/T1.112.1)
----------+-----------+---------------------------------------------
N-PCstate |Indication |ITU-Q.711 Chap 6.3.2.3.3 (Tab 1/Q.711)
| |ANSI-T1.112 Chap 2.3.2.3.4 (Tab 8G/T1.112.1)
----------+-----------+---------------------------------------------
N-Coord |Request |ITU-Q.711 Chap 6.3.2.3.1 (Tab 15/Q.711)
|Indication |ANSI-T1.112 Chap 2.3.2.3.3 (Tab 8F/T1.112.1)
|Response |
|Confirm |
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1.4.5. Support for the management between the SGP and ASP.
The SUA layer provides interworking with SCCP management functions at
the SG for operation between the switched circuit networks and the IP
network. It should:
* Provide an indication to the SCCP-user at an ASP that a SS7
endpoint/peer is unreachable.
* Provide an indication to the SCCP-user at an ASP that a SS7
endpoint/peer is reachable.
* Provide congestion indication to SCCP-user at an ASP.
* Provide the initiation of an audit of SS7 endpoints at the SG.
1.4.6. Relay function
For network scalability purposes, the SUA may be enhanced with a
relay functionality to determine the next hop SCTP association toward
the destination SUA endpoint.
The determination of the next hop may be based on Global Title
information (e.g., E.164 number), in analogy with SCCP GTT in SS7
networks, modeled in [ITU-T Q.714]. It may also be based on Hostname
information, IP address or pointcode contained in the called party
address.
This allows for greater scalability, reliability and flexibility in
wide-scale deployments of SUA. The usage of a relay function is a
deployment decision.
1.5. Internal Functions Provided in the SUA Layer
To perform its addressing and relaying capabilities, the SUA makes
use of an Address Mapping Function (AMF). This function is
considered part of SUA, but the way it is realized is left
implementation / deployment dependent (local tables, DNS [3761],
LDAP, etc.)
The AMF is invoked when a message is received at the incoming
interface. The AMF is responsible for resolving the address
presented in the incoming SCCP/SUA message to SCTP associations to
destinations within the IP network. The AMF will select the
appropriate SCTP association based upon routing context / routing key
information available. The destination might be the end SUA node or
a SUA relay node. The Routing Keys reference an Application Server,
which will have one or more ASPs processing traffic for the AS. The
availability and status of the ASPs is handled by SUA ASP management
messages.
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Possible SS7 address/routing information that comprise a Routing Key
entry includes, for example, OPC, DPC, SIO found in the MTP3 routing
label, SCCP subsystem number, or Transaction ID. IP addresses and
hostnames can also be used as Routing Key Information.
It is expected that the routing keys be provisioned via a MIB,
dynamic registration or external process, such as a database.
1.5.1. Address Mapping at the SG
Normally, one or more ASPs are active in the AS (i.e., currently
processing traffic) but in certain failure and transition cases it is
possible that there may not be an active ASP available. The SGP will
buffer the message destined for this AS for a time T(r) or until an
ASP becomes available. When no ASP becomes available before expiry
of T(r), the SGP will flush the buffered messages and initiate the
appropriate return or refusal procedures.
If there is no address mapping match for an incoming message, a
default treatment MAY be specified. Possible solutions are to
provide a default Application Server to direct all unallocated
traffic to a (set of) default ASP(s), or to drop the messages and
provide a notification to management. The treatment of unallocated
traffic is implementation dependent.
1.5.2. Address Mapping at the ASP
To direct messages to the SS7 network, the ASP MAY perform an address
mapping to choose the proper SGP for a given message. This is
accomplished by observing the Destination Point Code and other
elements of the outgoing message, SS7 network status, SGP
availability, and Routing Context configuration tables.
A Signalling Gateway may be composed of one or more SGPs. There is,
however, no SUA messaging to manage the status of an SGP. Whenever
an SCTP association to an SGP exists, it is assumed to be available.
Also, every SGP of one SG communicating with one ASP regarding one AS
provides identical SS7 connectivity to this ASP.
An ASP routes responses to the SGP that it received messages from;
within the routing context which it is currently active and receiving
traffic.
1.5.3. Address Mapping Function at a Relay Node
The relay function is invoked when:
- Routing is on Global Title
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- Routing is on Hostname
- Routing is on SSN and PC or SSN and IP Address and the address
presented is not the one of the relay node
Translation/resolution of the above address information yields one of
the following:
- Route on SSN: SCTP association ID toward the destination node, SSN
and optionally Routing Context and/or IP address.
- Route on GT: SCTP association ID toward next relay node, (new) GT
and optionally SSN and/or Routing Context.
- Routing on Hostname: SCTP association ID toward next relay node,
(new) Hostname and optionally SSN and/or Routing Context.
- A local SUA-user (combined relay/end node)
To prevent looping, an SS7 hop counter is used. The originating end
node (be it an SS7 or an IP node) sets the value of the SS7 hop
counter to the maximum value (15 or less). Each time the relay
function is invoked within an intermediate (relay) node, the SS7 hop
counter is decremented. When the value reaches zero, the return or
refusal procedures are invoked with reason "Hop counter violation".
1.5.4. SCTP Stream Mapping
The SUA supports SCTP streams. Signalling Gateway SG and Application
Servers need to maintain a list of SCTP and SUA-users for mapping
purposes. SCCP-users requiring sequenced message transfer need to be
sent over a stream with sequenced delivery.
SUA uses stream 0 for SUA management messages. It is OPTIONAL that
sequenced delivery be used to preserve the order of management
message delivery.
Stream selection based on protocol class:
- Protocol class 0: SUA MAY select unordered delivery. The stream
selected is based on traffic information available to the SGP or
ASP.
- Protocol class 1: SUA MUST select ordered delivery. The stream
selected is based upon the sequence parameter given by the upper
layer over the primitive interface and other traffic information
available to the SGP or ASP
- Protocol classes 2 and 3: SUA MUST select ordered delivery. The
stream selected is based upon the source local reference of the
connection and other traffic information available to the SGP or
ASP.
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1.5.5. Flow Control
Local Management at an ASP may wish to stop traffic across an SCTP
association to temporarily remove the association from service or to
perform testing and maintenance activity. The function could
optionally be used to control the start of traffic on to a newly
available SCTP association.
1.5.6. Congestion Management
The SUA layer is informed of local and IP network congestion by means
of an implementation-dependent function (e.g., an implementation-
dependent indication from the SCTP of IP network congestion).
At an ASP or IPSP, the SUA layer indicates congestion to local SCCP-
Users by means of an appropriate SCCP primitive (e.g., N-INFORM, N-
NOTICE), as per current SCCP procedures, to invoke appropriate upper
layer responses. When an SG determines that the transport of SS7
messages is encountering congestion, the SG MAY trigger SS7 SCCP
Congestion messages to originating SS7 nodes, per the congestion
procedures of the relevant SCCP standard. The triggering of SS7 SCCP
Management messages from an SG is an implementation-dependent
function.
The SUA layer at an ASP or IPSP MAY indicate local congestion to an
SUA peer with an SCON message. When an SG receives a congestion
message (SCON) from an ASP, and the SG determines that an endpoint is
now encountering congestion, it MAY trigger congestion procedures of
the relevant SCCP standard.
1.6. Definition of SUA Boundaries
1.6.1. Definition of the upper boundary
The following primitives are supported between the SUA and an SCCP-
user (a reference to ITU and ANSI sections where these primitives and
corresponding parameters are described, is also given):
Generic |Specific |
Name |Name |ANSI/ITU Reference
------------+----------+-------------------------------------------
N-CONNECT |Request |ITU-Q.711 Chap 6.1.1.2.2 (Tab 2/Q.711)
|Indication|ANSI-T1.112 Chap 2.1.1.2.2 (Tab 2/T1.112.1)
|Response |
|Confirm |
------------+----------+-------------------------------------------
N-DATA |Request |ITU-Q.711 Chap 6.1.1.2.3 (Tab 3/Q.711)
|Indication|ANSI-T1.112 Chap 2.1.1.2.3 (Tab 3/T1.112.1)
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------------+----------+-------------------------------------------
N-EXPEDITED |Request |ITU-Q.711 Chap 6.1.1.2.3 (Tab 4/Q.711)
DATA |Indication|ANSI-T1.112 Chap 2.1.1.2.3 (Tab 4/T1.112.1)
------------+----------+-------------------------------------------
N-RESET |Request |ITU-Q.711 Chap 6.1.1.2.3 (Tab 5/Q.711)
|Indication|ANSI-T1.112 Chap 2.1.1.2.3 (Tab 5/T1.112.1)
|Response |
|Confirm |
------------+----------+-------------------------------------------
N-DISCONNECT|Request |ITU-Q.711 Chap 6.1.1.2.4 (Tab 6/Q.711)
|Indication|ANSI-T1.112 Chap 2.1.1.2.4 (Tab 6/T1.112.1)
------------+----------+-------------------------------------------
N-INFORM |Request |ITU-Q.711 Chap 6.1.1.3.2 (Tab 8/Q.711)
|Indication|ANSI-T1.112 Chap 2.1.1.2.5 (Tab 6A/T1.112.1)
------------+----------+-------------------------------------------
N-UNITDATA |Request |ITU-Q.711 Chap 6.2.2.3.1 (Tab 12/Q.711)
|Indication|ANSI-T1.112 Chap 2.2.2.3.1 (Tab 8A/T1.112.1)
------------+----------+-------------------------------------------
N-NOTICE |Indication|ITU-Q.711 Chap 6.2.2.3.2 (Tab 13/Q.711)
| |ANSI-T1.112 Chap 2.2.2.3.2 (Tab 8B/T1.112.1)
------------+----------+--------------------------------------------
N-STATE |Request |ITU-Q.711 Chap 6.3.2.3.2 (Tab 16/Q.711)
|Indication|ANSI-T1.112 Chap 2.3.2.3.2 (Tab 8E/T1.112.1)
------------+----------+--------------------------------------------
N-PCSTATE |Indication|ITU-Q.711 Chap 6.3.2.3.3 (Tab 17/Q.711)
| |ANSI-T1.112 Chap 2.3.2.3.4 (Tab 8G/T1.112.1)
------------+----------+--------------------------------------------
N-COORD |Request |ITU-Q.711 Chap 6.3.2.3.1 (Tab 15/Q.711)
|Indication|ANSI-T1.112 Chap 2.3.2.3.3 (Tab 8F/T1.112.1)
|Response |
|Confirm |
1.6.2. Definition of the lower boundary
The upper layer primitives provided by the SCTP are provided in
[SCTP].
1.6.3. Definition of the Boundary between SUA and Layer Management
M-SCTP_ESTABLISH request
Direction: LM -> SUA
Purpose: LM requests ASP to establish an SCTP association with its
peer.
M-SCTP_ESTABLISH confirm
Direction: SUA -> LM
Purpose: ASP confirms to LM that it has established an SCTP
association with its peer.
Loughney, et al. Standards Track [Page 15]
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M-SCTP_ESTABLISH indication
Direction: SUA -> LM
Purpose: SUA informs LM that a remote ASP has established an SCTP
association.
M-SCTP_RELEASE request
Direction: LM -> SUA
Purpose: LM requests ASP to release an SCTP association with its
peer.
M-SCTP_RELEASE confirm
Direction: SUA -> LM
Purpose: ASP confirms to LM that it has released SCTP association
with its peer.
M-SCTP_RELEASE indication
Direction: SUA -> LM
Purpose: SUA informs LM that a remote ASP has released an SCTP
Association or the SCTP association has failed.
M-SCTP RESTART indication
Direction: SUA -> LM
Purpose: SUA informs LM that an SCTP restart indication has been
received.
M-SCTP_STATUS request
Direction: LM -> SUA
Purpose: LM requests SUA to report the status of an SCTP
association.
M-SCTP_STATUS confirm
Direction: SUA -> LM
Purpose: SUA responds with the status of an SCTP association.
M-SCTP STATUS indication
Direction: SUA -> LM
Purpose: SUA reports the status of an SCTP association.
M-ASP_STATUS request
Direction: LM -> SUA
Purpose: LM requests SUA to report the status of a local or remote
ASP.
M-ASP_STATUS confirm
Direction: SUA -> LM
Purpose: SUA reports status of local or remote ASP.
Loughney, et al. Standards Track [Page 16]
RFC 3868 SUA October 2004
M-AS_STATUS request
Direction: LM -> SUA
Purpose: LM requests SUA to report the status of an AS.
M-AS_STATUS confirm
Direction: SUA -> LM
Purpose: SUA reports the status of an AS.
M-NOTIFY indication
Direction: SUA -> LM
Purpose: SUA reports that it has received a Notify message from its
peer.
M-ERROR indication
Direction: SUA -> LM
Purpose: SUA reports that it has received an Error message from its
peer or that a local operation has been unsuccessful.
M-ASP_UP request
Direction: LM -> SUA
Purpose: LM requests ASP to start its operation and send an ASP Up
message to its peer.
M-ASP_UP confirm
Direction: SUA -> LM
Purpose: ASP reports that is has received an ASP UP Ack message
from its peer.
M-ASP_UP indication
Direction: SUA -> LM
Purpose: SUA reports it has successfully processed an incoming ASP
Up message from its peer.
M-ASP_DOWN request
Direction: LM -> SUA
Purpose: LM requests ASP to stop its operation and send an ASP Down
message to its peer.
M-ASP_DOWN confirm
Direction: SUA -> LM
Purpose: ASP reports that is has received an ASP Down Ack message
from its peer.
M-ASP_DOWN indication
Direction: SUA -> LM
Purpose: SUA reports it has successfully processed an incoming ASP
Down message from its peer, or the SCTP association has
been lost/reset.
Loughney, et al. Standards Track [Page 17]
RFC 3868 SUA October 2004
M-ASP_ACTIVE request
Direction: LM -> SUA
Purpose: LM requests ASP to send an ASP Active message to its peer.
M-ASP_ACTIVE confirm
Direction: SUA -> LM
Purpose: ASP reports that is has received an ASP Active Ack message
from its peer.
M-ASP_ACTIVE indication
Direction: SUA -> LM
Purpose: SUA reports it has successfully processed an incoming ASP
Active message from its peer.
M-ASP_INACTIVE request
Direction: LM -> SUA
Purpose: LM requests ASP to send an ASP Inactive message to its
peer.
M-ASP_INACTIVE confirm
Direction: LM -> SUA
Purpose: ASP reports that is has received an ASP Inactive
Ack message from its peer.
M-ASP_INACTIVE indication
Direction: SUA -> LM
Purpose: SUA reports it has successfully processed an incoming ASP
Inactive message from its peer.
M-AS_ACTIVE indication
Direction: SUA -> LM
Purpose: SUA reports that an AS has moved to the AS-ACTIVE state.
M-AS_INACTIVE indication
Direction: SUA -> LM
Purpose: SUA reports that an AS has moved to the AS-INACTIVE state.
M-AS_DOWN indication
Direction: SUA -> LM
Purpose: SUA reports that an AS has moved to the AS-DOWN state.
Loughney, et al. Standards Track [Page 18]
RFC 3868 SUA October 2004
If the SUA layer supports dynamic registration of Routing Key, the
layer MAY support the following additional primitives:
M-RK_REG request
Direction: LM -> SUA
Purpose: LM requests ASP to register RK(s) with its peer by sending
REG REQ message.
M-RK_REG confirm
Direction: SUA -> LM
Purpose: ASP reports that it has received REG RSP message with
registration status as successful from its peer.
M-RK_REG indication
Direction: SUA -> LM
Purpose: SUA informs LM that it has successfully processed an
incoming REG REQ message.
M-RK_DEREG request
Direction: LM -> SUA
Purpose: LM requests ASP to deregister RK(s) with its peer by
sending DEREG REQ message.
M-RK_DEREG confirm
Direction: SUA -> LM
Purpose: ASP reports that it has received DEREG RESP message with
deregistration status as successful from its peer.
M-RK_DEREG indication
Direction: SUA -> LM
Purpose: SUA informs LM that it has successfully processed an
incoming DEREG REQ from its peer.
2. Conventions
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when
they appear in this document, are to be interpreted as described in
BCP 14, RFC 2119 [2119].
3. Protocol Elements
The general message format includes a Common Message Header together
with a list of zero or more parameters as defined by the Message
Type.
For forward compatibility, all Message Types may have attached
parameters even if none are specified in this version.
Loughney, et al. Standards Track [Page 19]
RFC 3868 SUA October 2004
The Reserved field is set to 0 in messages sent and is not to be
examined in messages received.
3.1. Common Message Header
The protocol messages for the SCCP-User Adaptation Protocol requires
a message structure which contains a version, message class, message
type, message length and message contents. This message header is
common among all signalling protocol adaptation layers:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Reserved | Message Class | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Data |
Note that the 'data' portion of SUA messages SHALL contain SCCP-User
data, not the encapsulated SCCP message.
Optional parameters can only occur at most once in an SUA message.
3.1.1. SUA Protocol Version
The version field (ver) contains the version of the SUA adaptation
layer. The supported versions are:
1 SUA version 1.0
3.1.2. Message Classes
Message Classes
0 SUA Management (MGMT) Message
1 Reserved
2 Signalling Network Management (SNM) Messages
3 ASP State Maintenance (ASPSM) Messages
4 ASP Traffic Maintenance (ASPTM) Messages
5 Reserved
6 Reserved
7 Connectionless Messages
8 Connection-Oriented Messages
9 Routing Key Management (RKM) Messages.
10 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
Loughney, et al. Standards Track [Page 20]
RFC 3868 SUA October 2004
3.1.3. Message Types
SUA Management Messages
0 Error (ERR)
1 Notify (NTFY)
2 - 127 Reserved by the IETF
128- 255 Reserved for IETF-Defined Message Class Extensions
Signalling Network Management (SNM) Messages
0 Reserved
1 Destination Unavailable (DUNA)
2 Destination Available (DAVA)
3 Destination State Audit (DAUD)
4 Signalling Congestion (SCON)
5 Destination User Part Unavailable (DUPU)
6 Destination Restricted (DRST)
7 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
Application Server Process State Maintenance (ASPSM) Messages
0 Reserved
1 ASP Up (UP)
2 ASP Down (DOWN)
3 Heartbeat (BEAT)
4 ASP Up Ack (UP ACK)
5 ASP Down Ack (DOWN ACK)
6 Heartbeat Ack (BEAT ACK)
7 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
ASP Traffic Maintenance (ASPTM) Messages
0 Reserved
1 ASP Active (ACTIVE)
2 ASP Inactive (INACTIVE)
3 ASP Active Ack (ACTIVE ACK)
4 ASP Inactive Ack (INACTIVE ACK)
5 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
Loughney, et al. Standards Track [Page 21]
RFC 3868 SUA October 2004
Routing Key Management (RKM) Messages
0 Reserved
1 Registration Request (REG REQ)
2 Registration Response (REG RSP)
3 Deregistration Request (DEREG REQ)
4 Deregistration Response (DEREG RSP)
5 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
Connectionless (CL) Messages
0 Reserved
1 Connectionless Data Transfer (CLDT)
2 Connectionless Data Response (CLDR)
3 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
Connection-Oriented (CO) Messages
0 Reserved
1 Connection Request (CORE)
2 Connection Acknowledge (COAK)
3 Connection Refused (COREF)
4 Release Request (RELRE)
5 Release Complete (RELCO)
6 Reset Confirm (RESCO)
7 Reset Request (RESRE)
8 Connection Oriented Data Transfer (CODT)
9 Connection Oriented Data Acknowledge (CODA)
10 Connection Oriented Error (COERR)
11 Inactivity Test (COIT)
12 - 127 Reserved by the IETF
128 - 255 Reserved for IETF-Defined Message Class Extensions
3.1.4. Message Length
The Message Length defines the length of the message in octets,
including the header and including all padding bytes. Message Length
is a 32-bit identifier.
3.1.5. Tag-Length-Value Format
SUA messages consist of a Common Header followed by zero or more
parameters, as defined by the message type. The Tag-Length-Value
(TLV) parameters contained in a message are defined in a Tag-Length-
Value format as shown below.
Loughney, et al. Standards Track [Page 22]
RFC 3868 SUA October 2004
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Parameter Tag | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ Parameter Value /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameter Tag: 16 bits (unsigned integer)
Tag field is a 16-bit identifier of the type of parameter. It
takes a value of 0 to 65535.
Parameter Length: 16 bits (unsigned integer)
The Parameter Length field contains the size of the parameter in
bytes, including the Parameter Tag, Parameter Length, and
Parameter Value fields. The Parameter Length does not include any
padding bytes. However, composite parameters will contain all
padding bytes, since all parameters contained within this
composite parameter will be considered multiples of 4 bytes.
Parameter Value: variable-length.
The Parameter Value field contains the actual information to be
transfered in the parameter.
The total length of a parameter (including Tag, Parameter Length
and Value fields) MUST be a multiple of 4 bytes. If the length of
the parameter is not a multiple of 4 bytes, the sender pads the
parameter at the end (i.e., after the Parameter Value field) with
all zero bytes. The length of the padding is NOT included in the
parameter length field. A sender SHOULD NOT pad with more than 3
bytes. The receiver MUST ignore the padding bytes.
Implementation note: The use of TLV in principle allows the
parameters to be placed in a random order in the message. However,
some guidelines should be considered for easy processing in the
following order:
- Parameters needed to correctly process other message parameters,
preferably should precede these parameters (such as Routing
Context).
- Mandatory parameters preferably SHOULD precede any optional
parameters.
- The data parameter will normally be the final one in the message.
Loughney, et al. Standards Track [Page 23]
RFC 3868 SUA October 2004
- The receiver SHOULD accept parameters in any order, except where
explicitly mandated.
3.2. SUA Connectionless Messages
The following section describes the SUA Connectionless transfer
messages and parameter contents. The general message format includes
a Common Message Header together with a list of zero or more
parameters as defined by the Message Type. All Message Types can
have attached parameters.
3.2.1. Connectionless Data Transfer (CLDT)
This message transfers data between one SUA to another.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0115 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Class |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0116 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Control |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SS7 Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
Loughney, et al. Standards Track [Page 24]
RFC 3868 SUA October 2004
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0013 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0117 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Segmentation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010B | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Protocol Class Mandatory
Source Address Mandatory
Destination Address Mandatory
Sequence Control Mandatory
SS7 Hop Count Optional
Importance Optional
Message Priority Optional
Correlation ID Optional
Segmentation Optional
Data Mandatory
Implementation note: This message covers the following SCCP messages:
unitdata (UDT), extended unitdata (XUDT), long unitdata (LUDT).
3.2.2. Connectionless Data Response (CLDR)
This message is used as a response message by the peer to report
errors in the received CLDT message, when the return on error option
is set.
Loughney, et al. Standards Track [Page 25]
RFC 3868 SUA October 2004
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SS7 Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0013 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0117 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Segmentation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 26]
RFC 3868 SUA October 2004
Parameters
Routing Context Mandatory
SCCP Cause Mandatory
Source Address Mandatory
Destination Address Mandatory
SS7 Hop Count Optional
Importance Optional
Message Priority Optional
Correlation ID Optional
Segmentation Optional
Data Optional
Implementation note: This message covers the following SCCP messages:
unitdata service (UDTS), extended unitdata service (XUDTS) and long
unitdata service (LUDTS).
3.3. Connection Oriented Messages
3.3.1. Connection Oriented Data Transfer (CODT)
This message transfers data between one SUA to another for
connection-oriented service.
Loughney, et al. Standards Track [Page 27]
RFC 3868 SUA October 2004
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0013 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Sequence Number Optional *1
Destination Reference Number Mandatory
Message Priority Optional
Correlation ID Optional
Data Mandatory
NOTE *1: This parameter is not present in case of Expedited Data
(ED).
Implementation note: For the CODT to represent DT1, DT2 and ED
messages, the following conditions MUST be met:
DT1 is represented by a CODT when:
Sequence Number parameter is present (contains "more" indicator).
Loughney, et al. Standards Track [Page 28]
RFC 3868 SUA October 2004
DT2 is represented by a CODT when:
Sequence Number parameter is present (contains P(S), P(R) and more
indicator)
ED is represented by a CODT with:
Sequence Number parameter is not present
3.3.2. Connection Oriented Data Acknowledge (CODA)
The peer uses this message to acknowledge receipt of data. This
message is used only with protocol class 3.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0108 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
Receive Sequence Number Optional *1
Credit Mandatory *1
NOTE *1: Mandatory when representing Data Acknowledgement (AK).
Implementation note: For the CODA to represent DA and EA messages,
the following conditions MUST be met:
DA is represented by a CODA when:
Receive Sequence Number parameter is present (contains P(S), P(R)
and more indicator)
Loughney, et al. Standards Track [Page 29]
RFC 3868 SUA October 2004
EA is represented by a CODA when:
Receive Sequence Number parameter is not present
3.3.3. Connection Request (CORE)
This message is used for establishing a signalling connection between
two peer endpoints.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0115 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Class |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0116 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Control |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SS7 Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 30]
RFC 3868 SUA October 2004
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Protocol Class Mandatory
Source Reference Number Mandatory
Destination Address Mandatory
Sequence Control Mandatory
Sequence Number Optional *1
Source Address Optional
SS7 Hop Count Optional
Importance Optional
Message Priority Optional
Credit Optional *1
Data Optional
NOTE *1: Mandatory for protocol class 3 only.
Implementation note: This message covers the following SCCP message:
Connection Request (CR).
Loughney, et al. Standards Track [Page 31]
RFC 3868 SUA October 2004
3.3.4. Connection Acknowledge (COAK)
This message is used to acknowledge a connection request from the
peer endpoint.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0115 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Class |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x01116 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Control |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 32]
RFC 3868 SUA October 2004
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Protocol Class Mandatory
Destination Reference Number Mandatory
Source Reference Number Mandatory
Sequence Control Mandatory
Credit Mandatory *2
Source Address Optional
Importance Optional
Message Priority Optional
Destination Address Optional *1
Data Optional
NOTE *1: Destination Address parameter will be present in case
that the received CORE message conveys the Source
Address parameter.
NOTE *2: Only applicable for protocol class 3.
Implementation note: This message covers the following SCCP message:
Connection Confirm (CC).
Loughney, et al. Standards Track [Page 33]
RFC 3868 SUA October 2004
3.3.5. Connection Refused (COREF)
This message is used to refuse a connection request between two peer
endpoints.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010B | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 34]
RFC 3868 SUA October 2004
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
SCCP Cause Mandatory
Source Address Optional
Destination Address Optional *1
Importance Optional
Data Optional
Note *1: Destination Address parameter will be present in case
that the received CORE message conveys the Source Address
parameter.
Implementation note: This message covers the following SCCP message:
Connection REFused (CREF).
Loughney, et al. Standards Track [Page 35]
RFC 3868 SUA October 2004
3.3.6. Release Request (RELRE)
This message is used to request a signalling connection between two
peer endpoints be released. All associated resources can then be
released.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
Source Reference Number Mandatory
SCCP Cause Mandatory
Importance Optional
Data Optional
Implementation note: This message covers the following SCCP message:
connection ReLeaSeD (RLSD).
Loughney, et al. Standards Track [Page 36]
RFC 3868 SUA October 2004
3.3.7. Release Complete (RELCO)
This message is used to acknowledge the release of a signalling
connection between two peer endpoints. All associated resources
should be released.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
Source Reference Number Mandatory
Importance Optional
Implementation note: This message covers the following SCCP message:
ReLease Complete (RLC).
Loughney, et al. Standards Track [Page 37]
RFC 3868 SUA October 2004
3.3.8. Reset Request (RESRE)
This message is used to indicate that the sending SCCP/SUA wants to
initiate a reset procedure (reinitialization of sequence numbers) to
the peer endpoint.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
Source Reference Number Mandatory
SCCP Cause Mandatory
Implementation note: This message covers the following SCCP message:
ReSet Request (RSR).
Loughney, et al. Standards Track [Page 38]
RFC 3868 SUA October 2004
3.3.9. Reset Confirm (RESCO)
This message is used to confirm the Reset Request.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
Source Reference Number Mandatory
Implementation note: This message covers the following SCCP message:
ReSet Confirmation (RSC).
Loughney, et al. Standards Track [Page 39]
RFC 3868 SUA October 2004
3.3.10. Connection Oriented Error (COERR)
The COERR message is sent to indicate a protocol data unit error.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Destination Reference Number Mandatory
SCCP Cause Mandatory
Implementation note: This message covers the following SCCP message:
Protocol Data Unit ERRor (ERR).
Loughney, et al. Standards Track [Page 40]
RFC 3868 SUA October 2004
3.3.11. Connection Oriented Inactivity Test (COIT)
This message is used for auditing the signalling connection state and
the consistency of connection data at both ends of the signalling
connection.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0115 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Class |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Mandatory
Protocol Class Mandatory
Source Reference Number Mandatory
Destination Reference number Mandatory
Sequence Number Mandatory *1
Credit Mandatory *1
NOTE *1: Information in these parameter fields reflects those
values sent in the last data form 2 or data
acknowledgement message. They are ignored if the
protocol class indicates class 2.
Loughney, et al. Standards Track [Page 41]
RFC 3868 SUA October 2004
Implementation note: This message covers the following SCCP message:
Inactivity Test (IT).
3.4. Signalling Network Management (SNM) Messages
3.4.1. Destination Unavailable (DUNA)
In the scope of SUA, this message is covered by the PC- or N-state
indication passed between SCCP and local SCCP-user. The DUNA message
is sent from the SG or relay node to all concerned ASPs (servicing
SCCP-users considered local to the SG or relay node, see chapter
1.3.1.1), when a destination or SCCP-user has become unreachable. The
SUA-User at the ASP is expected to stop traffic to the affected
destination or SCCP-user through the SG or relay node initiating the
DUNA.
The format for DUNA Message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0112 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SMI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 42]
RFC 3868 SUA October 2004
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
SSN Optional *1
SMI Optional
Info String Optional
Note 1: When the SSN is included, the DUNA message
corresponds to the SCCP N-STATE primitive. When SSN
is not, the DUNA message corresponds to the SCCP N-PCSTATE
primitive. The Affected Point Code parameter can only
contain one point code when SSN is present.
3.4.2. Destination Available (DAVA)
In the scope of SUA, this message is covered by the PC- and N-state
indication passed between SCCP and local SCCP-user. The DAVA message
is sent from the SG or relay node to all concerned ASPs (servicing
SCCP-users considered local to the SG or relay node, see chapter
1.3.1.1) to indicate that a destination (PC or SCCP-user) is now
reachable. The ASP SUA-User protocol is expected to resume traffic
to the affected destination through the SG or relay node initiating
the DAVA.
Loughney, et al. Standards Track [Page 43]
RFC 3868 SUA October 2004
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0112 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SMI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
SSN Optional *1
SMI Optional
Info String Optional
Note 1: When the SSN is included, the DAVA message corresponds to
the SCCP N-STATE primitive. When SSN is not included, the
DAVA message corresponds to the SCCP N-PCSTATE primitive.
The Affected Point Code can only contain one point code
when SSN is present.
3.4.3. Destination State Audit (DAUD)
The DAUD message can be sent from the ASP to the SG (or relay node)
to query the availability state of the routes to an affected
destination. A DAUD may be sent periodically after the ASP has
received a DUNA, until a DAVA is received. The DAUD can also be sent
when an ASP recovers from isolation from the SG (or relay node).
Loughney, et al. Standards Track [Page 44]
RFC 3868 SUA October 2004
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010C | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| User/Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
SSN Optional *1
User / Cause Optional
Info String Optional
Note 1: If the SSN is present, the DAUD is "soliciting" N-STATE
primitives, otherwise it is "soliciting" N-PCSTATE
primitives.
Loughney, et al. Standards Track [Page 45]
RFC 3868 SUA October 2004
3.4.4. Signalling Congestion (SCON)
The SCON message can be sent from the SG or relay node to all
concerned ASPs to indicate that the congestion level in the SS7
network to a specified destination has changed.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0118 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Congestion Level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0112 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SMI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
SSN Optional *1
Congestion Level Mandatory
SMI Optional
Info String Optional
Note 1: When the SSN is included, the SCON message corresponds to
the SCCP N-STATE primitive. When the SSN is not
included, the SCON message corresponds to the SCCP
Loughney, et al. Standards Track [Page 46]
RFC 3868 SUA October 2004
N-PCSTATE primitive reporting signalling point or network
congestion status.
3.4.5. Destination User Part Unavailable (DUPU)
The DUPU message is used by an SG to inform an ASP that a remote peer
at an SS7 node is unavailable.
The format for DUPU message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010C | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| User/Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
User/Cause Mandatory
Info String Optional
Note 1: The DUPU corresponds to the SCCP N-PCSTATE primitive.
3.4.6. Destination Restricted (DRST)
The DRST message is optionally sent from the SG to all concerned ASPs
to indicate that the SG has determined that one or more destinations
are now restricted from the point of view of the SG, or in response
to a DAUD message if appropriate. The SUA layer at the ASP is
Loughney, et al. Standards Track [Page 47]
RFC 3868 SUA October 2004
expected to send traffic to the affected destination via an alternate
SG of equal priority, but only if such an alternate route exists and
is available. If the ASP currently considers the affected
destination unavailable, the peer should be informed that traffic to
the affected destination could be resumed. In this case, the SUA
layer should route the traffic through the SG initiating the DRST
message.
This message is optional for the SG to send and it is optional for
the ASP to act on any information received in the message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0112 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SMI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
Affected Point Code Mandatory *1
SSN Optional *1
SMI Optional *1
Info String Optional
Note 1: The Affected Point Code refers to the node to which
become restricted or which has requested coordinated
service outage. When SSN is included in the message
Loughney, et al. Standards Track [Page 48]
RFC 3868 SUA October 2004
parameter, the DRST message corresponds to the SCCP
N-COORD primitive. If the SMI parameter is also included
in the message, the DRST message corresponds to the
N-COORD Request and N-COORD Indication primitives,
otherwise, the DRST message correspondence to the N-COORD
Response and N-COORD Confirm primitives. The Affected
Point Code can only contain one point code when SSN is
present. When SSN is not present, DRST corresponds to
N-PCSTATE primitive.
3.5. Application Server Process State Maintenance Messages
3.5.1. ASP Up (UP)
The ASP UP (UP) message is used to indicate to a remote SUA peer that
the Adaptation layer is up and running.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0011 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
ASP Identifier Optional *1
Info String Optional
Note 1: ASP Identifier MUST be used where the IPSP/SGP cannot
identify the ASP by provisioned address/port number
information (e.g., where an ASP is resident on a Host
using dynamic address/port number assignment).
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3.5.2. ASP Up Ack (UP ACK)
The ASP UP Ack message is used to acknowledge an ASP-Up message
received from a remote SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Info String Optional
3.5.3. ASP Down (DOWN)
The ASP Down (DOWN) message is used to indicate to a remote SUA peer
that the adaptation layer is not running.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Info String Optional
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3.5.4. ASP Down Ack (DOWN ACK)
The ASP DOWN Ack message is used to acknowledge an ASP-Down message
received from a remote SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Info String Optional
Note: ASP DOWN ACK will always be sent to acknowledge an ASP DOWN.
3.5.5. Heartbeat (BEAT)
The Heartbeat message is optionally used to ensure that the SUA peers
are still available to each other.
The format for the BEAT message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0009 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Heartbeat Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Heartbeat Data Optional
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3.5.6. Heartbeat Ack (BEAT ACK)
The Heartbeat ACK message is sent in response to a BEAT message. A
peer MUST send a BEAT ACK in response to a BEAT message. It includes
all the parameters of the received Heartbeat message, without any
change.
The format for the BEAT ACK message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0009 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Heartbeat Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Heartbeat Data Optional
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3.6. ASP Traffic Maintenance Messages
3.6.1. ASP Active (ACTIVE)
The ASPAC message is sent by an ASP to indicate to a remote SUA peer
that it is Active and ready to process signalling traffic for a
particular Application Server.
The format for the ACTIVE message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000B | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0110 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TID Label |
+-------------------------------+-------------------------------+
| Tag = 0x010F | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DRN Label |
+-------------------------------+-------------------------------+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Traffic Mode Type Optional
Routing Context Optional
TID Label Optional
DRN Label Optional
Info String Optional
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3.6.2. ASP Active Ack (ACTIVE ACK)
The ASPAC Ack message is used to acknowledge an ASP-Active message
received from a remote SUA peer.
The format for the ACTIVE Ack message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000B | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Traffic Mode Type Optional
Routing Context Mandatory
Info String Optional
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3.6.3. ASP Inactive (INACTIVE)
The INACTIVE message is sent by an ASP to indicate to a remote SUA
peer that it is no longer processing signalling traffic within a
particular Application Server.
The format for the ASPIA message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Routing Context Optional
INFO String Optional
3.6.4. ASP Inactive Ack (INACTIVE ACK)
The INACTIVE Ack message is used to acknowledge an ASP-Inactive
message received from a remote SUA peer.
The format for the INACTIVE Ack message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 55]
RFC 3868 SUA October 2004
Parameters
Routing Context Optional
INFO String Optional
3.7. SUA Management Messages
These messages are used for managing SUA and the representations of
the SCCP subsystems in the SUA layer.
3.7.1. Error (ERR)
The ERR message is sent between two SUA peers to indicate an error
situation. The Diagnostic Information parameter is optional,
possibly used for error logging and/or debugging.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000C | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Affected PC 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Affected PC n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010D | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0007 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Diagnostic Info /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Loughney, et al. Standards Track [Page 56]
RFC 3868 SUA October 2004
Parameters
Error Code Mandatory
Routing Context Mandatory *1
Network Appearance Mandatory *1
Affected Point Code Mandatory *1
Diagnostic Information Optional
Note 1: Only mandatory for specific error codes.
3.7.2. Notify (NTFY)
The Notify message used to provide an autonomous indication of SUA
events to an SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000D | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0011 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The NTFY message contains the following parameters:
Parameters
Status Mandatory
ASP Identifier Optional *1
Routing Context Optional
Info String Optional
Note 1: ASP Identifier MUST be used where the IPSP/SGP cannot
identify the ASP by provisioned address/port number
information (e.g., where an ASP is resident on a Host
using dynamic address/port number assignment).
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3.8. Routing Key Management (RKM) Messages
3.8.1. Registration Request (REG REQ)
The REG REQ message is sent by an ASP to indicate to a remote SUA
peer that it wishes to register one or more given Routing Keys with
the remote peer. Typically, an ASP would send this message to an
SGP, and expects to receive a REG RSP message in return with an
associated Routing Context value.
The format for the REG REQ message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010E | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Key 1 /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010E | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Key n /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0109 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The REG REQ message contains the following parameters:
Parameters
Routing Key Mandatory *1
ASP Capabilities Optional
Note 1: One or more Routing Key parameters MAY be included in a
single REG REQ message.
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3.8.2. Registration Response (REG RSP)
The REG RSP message is sent by an SG to an ASP indicate the result of
a previous REG REQ from an ASP. It contains indications of
success/failure for registration requests and returns a unique
Routing Context value for successful registration requests, to be
used in subsequent SUA Traffic Management protocol messages.
The format for the REG RSP message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0014 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Registration Result 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0014 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Registration Result n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The REG RSP message contains the following parameters:
Parameters
Registration Result Mandatory *1
Note 1: One or more Registration Result parameters MAY be included
in a single REG RSP message. The number of results in a
single REG RSP message can be anywhere from one to the
total number of Routing Key parameters found in the
corresponding REG REQ message.
3.8.3. Deregistration Request (DEREG REQ)
The DEREG REQ message is sent by an ASP to indicate to a remote SUA
peer that it wishes to deregister a given Routing Key. Typically, an
ASP would send this message to an SGP, and expects to receive a DEREG
RSP message in return with the associated Routing Context value.
Loughney, et al. Standards Track [Page 59]
RFC 3868 SUA October 2004
The format for the DEREG REQ message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The DEREG REQ message contains the following parameters:
Parameters
Routing Context Mandatory
3.8.4. Deregistration Response (DEREG RSP)
The DEREG RSP message is used as a response to the DEREG REQ message
from a remote SUA peer.
The format for the DEREG RSP message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0015 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Deregistration Result 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0015 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Deregistration Result n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The DEREG RSP message contains the following parameters:
Parameters
Deregistration Result Mandatory *1
Note 1: One or more Deregistration Result parameters MAY be
included in one DEREG RSP message. The number of results
in a single DEREG RSP message can be anywhere from one to
the total number of Routing Context parameters found in
the corresponding DEREG REQ message.
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3.9. Common Parameters
These TLV parameters are common across the different adaptation
layers.
Parameter Name Parameter ID
============== ============
Reserved 0x0000
Not used in SUA 0x0001
Not used in SUA 0x0002
Not used in SUA 0x0003
Info String 0x0004
Not used in SUA 0x0005
Routing Context 0x0006
Diagnostic Info 0x0007
Not used in SUA 0x0008
Heartbeat Data 0x0009
Not Used in SUA 0x000A
Traffic Mode Type 0x000B
Error Code 0x000C
Status 0x000D
Not used in SUA 0x000E
Not used in SUA 0x000F
Not used in SUA 0x0010
ASP Identifier 0x0011
Affected Point Code 0x0012
Correlation ID 0x0013
Registration Result 0x0014
Deregistration Result 0x0015
Registration Status 0x0016
Deregistration Status 0x0017
Local Routing Key Identifier 0x0018
3.9.1. Not Used
Use of Parameter ID 0x0001 in SUA messages is not supported.
3.9.2. Not Used
Use of Parameter ID 0x0002 in SUA messages is not supported.
3.9.3. Not Used
Use of Parameter ID 0x0003 in SUA messages is not supported.
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3.9.4. Info String
The optional INFO String parameter can carry any meaningful UTF-8
[3629] character string along with the message. Length of the INFO
String parameter is from 0 to 255 octets. No procedures are
presently identified for its use but service providers may use the
INFO String for debugging purposes.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Info String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.9.5. Not Used in SUA
Use of Parameter ID 0x0005 in SUA messages is not supported.
3.9.6. Routing Context
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Routing Context parameter contains (a list of) 4-byte unsigned
integers indexing the Application Server traffic that the sending ASP
is configured/registered to receive. There is a one-to-one
relationship between an index entry and a Routing Key or AS Name.
An Application Server Process may be configured to process traffic
for more than one logical Application Server. From the perspective
of an ASP, a Routing Context defines a range of signalling traffic
that the ASP is currently configured to receive from the SG.
Additionally, the Routing Context parameter identifies the SS7
network context for the message, for the purposes of logically
separating the signalling traffic between the SGP and the Application
Server Process over a common SCTP Association, when needed. An
example is where an SGP is logically partitioned to appear as an
Loughney, et al. Standards Track [Page 62]
RFC 3868 SUA October 2004
element in several different national SS7 networks. It implicitly
defines the SS7 Point Code format used, the SS7 Network Indicator
value and SCCP protocol type/variant/version used within a separate
SS7 network. It also defines the network context for the PC and SSN
values. Where an SGP operates in the context of a single SS7
network, or individual SCTP associations are dedicated to each SS7
network context, this functionality is not needed.
If the Routing Context parameter is present, it SHOULD be the first
parameter in the message as it defines the format and/or
interpretation of the parameters containing a PC or SSN value.
3.9.7. Diagnostic Information
The Diagnostic Information can be used to convey any information
relevant to an error condition, to assist in the identification of
the error condition. In the case of an Adaptation Layer Identifier
or Traffic Handling Mode, the Diagnostic Information includes the
received parameter. In the other cases, the Diagnostic information
may be the first 40 bytes of the offending message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0007 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Diagnostic Information /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.9.8. Not Used
Parameter ID 0x0008 is not used in SUA.
3.9.9. Heartbeat Data
The sending node defines the Heartbeat Data field contents. It may
include a Heartbeat Sequence Number and/or Timestamp, or other
implementation specific details.
The receiver of a Heartbeat message does not process this field as it
is only of significance to the sender. The receiver echoes the
content of the Heartbeat Data in a BEAT-Ack message.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0009 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Heartbeat Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The data field can be used to store information in the heartbeat
message useful to the sending node (e.g., the data field can contain
a time stamp, a sequence number, etc.).
3.9.10. Not Used
Parameter ID 0x000A is not used in SUA.
3.9.11. Traffic Mode Type
The Traffic Mode Type parameter identifies the traffic mode of
operation of the ASP within an AS.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000B | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Type are shown in the following table.
1 Override
2 Loadshare
3 Broadcast
Within a Routing Context, Override, Loadshare Types and Broadcast
cannot be mixed. The Override value indicates that the ASP is
operating in Override mode, and the ASP wishes to take over all
traffic for an Application Server (i.e., primary/backup operation),
overriding any currently active ASP in the AS. In Loadshare mode,
the ASP wishes to share in the traffic distribution with any other
currently active ASPs. In Broadcast mode, the ASP wishes to receive
the same traffic as any other currently active ASPs. When there are
insufficient ASPs, the sender may immediately move the ASP to Active.
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3.9.12. Error Code
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag =0x000C | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Error Code parameter indicates the reason for the Error Message.
The Error parameter value can be one of the following values:
0x01 Invalid Version
0x02 Not Used in SUA
0x03 Unsupported Message Class
0x04 Unsupported Message Type
0x05 Unsupported Traffic Handling Mode
0x06 Unexpected Message
0x07 Protocol Error
0x08 Not used in SUA
0x09 Invalid Stream Identifier
0x0a Not used in SUA
0x0b Not used in SUA
0x0c Not used in SUA
0x0d Refused - Management Blocking
0x0e ASP Identifier Required
0x0f Invalid ASP Identifier
0x10 Not Used in SUA
0x11 Invalid Parameter Value
0x12 Parameter Field Error
0x13 Unexpected Parameter
0x14 Destination Status Unknown
0x15 Invalid Network Appearance
0x16 Missing Parameter
0x17 Not Used in SUA
0x18 Not Used in SUA
0x19 Invalid Routing Context
0x1a No Configured AS for ASP
0x1b Subsystem Status Unknown
0x1c Invalid loadsharing label
The "Invalid Version" error is sent if a message was received with an
invalid or unsupported version. The Error message contains the
supported version in the Common header. The Error message could
optionally provide the unsupported version in the Diagnostic
information area.
Loughney, et al. Standards Track [Page 65]
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The "Unsupported Message Class" error is sent if a message with an
unexpected or unsupported Message Class is received.
The "Unsupported Message Type" error is sent if a message with an
unexpected or unsupported Message Type is received.
The "Unsupported Traffic Handling Mode" error is sent by a SGP if an
ASP sends an ASP Active message with an unsupported Traffic Mode Type
or a Traffic Mode Type that is inconsistent with the presently
configured mode for the Application Server. An example would be a
case in which the SGP did not support loadsharing.
The "Unexpected Message" error MAY be sent if a defined and
recognized message is received that is not expected in the current
state (in some cases the ASP may optionally silently discard the
message and not send an Error message). For example, silent discard
is used by an ASP if it received a DATA message from an SGP while it
was in the ASP-INACTIVE state. If the Unexpected message contained
Routing Context(s), the Routing Context(s) SHOULD be included in the
Error message.
The "Protocol Error" error is sent for any protocol anomaly (i.e.,
reception of a parameter that is syntactically correct but unexpected
in the current situation.
The "Invalid Stream Identifier" error is sent if a message is
received on an unexpected SCTP stream.
The "Refused - Management Blocking" error is sent when an ASP Up or
ASP Active message is received and the request is refused for
management reasons (e.g., management lockout"). If this error is in
response to an ASP Active message, the Routing Context(s) in the ASP
Active message SHOULD be included in the Error message.
The "ASP Identifier Required" is sent by a SGP in response to an ASP
Up message that does not contain an ASP Identifier parameter when the
SGP requires one. The ASP SHOULD resend the ASP Up message with an
ASP Identifier.
The "Invalid ASP Identifier" is send by a SGP in response to an ASP
Up message with an invalid ASP Identifier.
The "Invalid Parameter Value" error is sent if a message is received
with an invalid parameter value (e.g., a DUPU message was received
with a Mask value other than "0".
The "Parameter Field Error" would be sent if a message is received
with a parameter having a wrong length field.
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The "Unexpected Parameter" error would be sent if a message contains
an invalid parameter.
The "Invalid Network Appearance" error is sent by a SGP if an ASP
sends a message with an invalid (not configured) Network Appearance
value. For this error, the invalid (not configured) Network
Appearance MUST be included in the Network Appearance parameter.
The "Missing Parameter" error would be sent if a mandatory parameter
were not included in a message.
The "Invalid Routing Context" error would be sent by a SG if an ASP
sends a message with an invalid (not configured) Routing Context
value. For this error, the invalid (not configured) Routing
Context(s) MUST be included in the Routing Context parameter.
The "No Configured AS for ASP" error is sent if a message is received
from a peer without a Routing Context parameter and it is not known
by configuration data, which Application Servers are referenced.
The "Destination Status Unknown" Error MAY be sent if a DAUD is
received at an SG inquiring of the availability or congestion status
of a destination, and the SG does not wish to provide the status
(e.g., the sender is not authorized to know the status). For this
error, the invalid or unauthorized Point Code(s) MUST be included
along with the Network Appearance and Routing Context associated with
the Point Code(s).
The "Subsystem Status Unknown" Error MAY be sent if a DAUD is
received at an SG inquiring of the availability or congestion status
of a subsystem, and the SG does not wish to provide the status (e.g.,
the sender is not authorized to know the status). For this error,
the invalid or unauthorized Point Code and Subsystem Number MUST be
included along with the Network Appearance and Routing Context
associated with the Point Code and Subsystem Number.
3.9.13. Status
The Status parameter identifies the type of the status that is being
notified and the Status ID.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000D | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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RFC 3868 SUA October 2004
The valid values for Status Type (16 bit unsigned integer) are:
1 Application Server state change (AS_State_Change)
2 Other
The Status ID parameter contains more detailed information for the
notification, based on the value of the Status Type.
If the Status Type is AS_STATE_CHANGE, then the Status ID (16 bit
unsigned integer) values are:
1 reserved
2 Application Server Inactive (AS-Inactive)
3 Application Server Active (AS-Active)
4 Application Server Pending (AS-Pending)
These notifications are sent from an SGP to an ASP upon a change in
status of a particular Application Server. The value reflects the
new state of the Application Server.
If the Status Type is "Other", then the following Status Information
values are defined:
1 Insufficient ASP resources active in AS
2 Alternate ASP Active
3 ASP failure
These notifications are not based on the SGP reporting the state
change of an ASP or AS. In the Insufficient ASP Resources case, the
SGP is indicating to an "Inactive" ASP(s) in the AS that another ASP
is required to handle the load of the AS (Loadsharing mode or
Broadcast mode). For the Alternate ASP Active case, an ASP is
informed when an alternate ASP transitions to the ASP-Active state in
Override mode.
3.9.14. Not Used in SUA
Parameter ID 0x000E is not used in SUA.
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RFC 3868 SUA October 2004
3.9.15. Not Used in SUA
Parameter ID 0x000F is not used in SUA.
3.9.16. Not Used in SUA
Parameter ID 0x0010 is not used in SUA.
3.9.17. ASP Identifier
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0011 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ASP Identifier field: 32-bits (unsigned integer)
The ASP Identifier field contains a unique value that is locally
significant among the ASPs that support an AS. The SGP should save
the ASP Identifier to be used, if necessary, with the Notify message
(see Section 3.7.2).
3.9.18. Affected Point Code
The Affected Point Code Destinations parameter contains a list of
Affected Point Code fields, each a three-octet parameter to allow for
14-, 16- and 24-bit binary formatted SS7 Point Codes. Affected Point
Codes that are less than 24-bits are padded on the left to the 24-bit
boundary.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0012 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Affected PC 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ . . . /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The encoding is shown below for ANSI and ITU Point Code examples.
Loughney, et al. Standards Track [Page 69]
RFC 3868 SUA October 2004
ANSI 24-bit Point Code:
0 1 2 3-->
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Network | Cluster | Member |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MSB-----------------------------------------LSB|
ITU 14-bit Point Code:
0 1 2 3-->
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask |0 0 0 0 0 0 0 0 0 0|Zone | Region | SP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MSB--------------------LSB|
It is OPTIONAL for an implementation to generate an Affected Point
Code parameter with more than on Affected PC but the implementation
MUST accept and process an Affected Point Code parameter with more
than one Affected PC.
Mask: 8-bits
The Mask parameter can be used to identify a contiguous range of
Affected Destination Point Codes, independent of the point code
format. Identifying a contiguous range of Affected PCs may be useful
when reception of an MTP3 management message or a linkset event
simultaneously affects the availability status of a series of
destinations at an SG.
The Mask parameter is an integer representing a bit mask that can be
applied to the related Affected PC field. The bit mask identifies
how many bits of the Affected PC field are significant and which are
effectively "wild-carded". For example, a mask of "8" indicates that
the last eight bits of the PC is "wild-carded". For an ANSI 24-bit
Affected PC, this is equivalent to signalling that all PCs in an ANSI
Cluster are unavailable. A mask of "3" indicates that the last three
bits of the PC is "wild-carded". For a 14-bit ITU Affected PC, this
is equivalent to signalling that an ITU Region is unavailable.
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3.9.19. Correlation ID
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0013 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Correlation ID is a 32-bit identifier that is attached to CLDT
messages to indicate to a newly entering ASP in a Broadcast AS where
in the traffic flow of CLDT messages the ASP is joining. It is
attached to the first CLDT message sent to an ASP by an SG after
sending an ASP Active Ack or otherwise starting traffic to an ASP.
The Correlation ID is only significant within a Routing Context.
Implementation note: Correlation ID parameter can be used for
features like Synchronisation of ASPs/SGPs in a Broadcast Mode AS/SG;
avoid message duplication and mis-sequencing in case of failover of
association from one ASP/SGP to other ASP/SGP etc.
3.9.20. Registration Result
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0018 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0016 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Registration Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Routing Key Identifier contains the same TLV formatted parameter
value as found in the matching Routing Key parameter in the REG REQ
message.
Routing Context contains the same TLV formatted Routing Context
parameter for the associated Routing Key if the registration was
successful. It is set to "0" if the registration was not successful.
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3.9.21. Deregistration Result
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Context |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0017 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Deregistration Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Routing Context: 32-bit integer
Routing Context contains the Routing Context value of the matching
Routing key to deregister, as found in the DEREG REQ message.
Deregistration Status: 32-bit integer
Deregistration Status parameter indicates the success or the
reason for failure of the deregistration.
3.9.22. Registration Status
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0016 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Registration Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Registration Status: 32-bits (unsigned integer)
The Registration Status field indicates the success or the reason
for failure of a registration request.
Its values may be:
0 Successfully Registered
1 Error - Unknown
2 Error - Invalid Destination Address
3 Error - Invalid Network Appearance
4 Error - Invalid Routing Key
5 Error - Permission Denied
6 Error - Cannot Support Unique Routing
7 Error - Routing Key not Currently Provisioned
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8 Error - Insufficient Resources
9 Error - Unsupported RK parameter Field
10 Error - Unsupported/Invalid Traffic Mode Type
11 Error - Routing Key Change Refused
3.9.23. Deregistration Status
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0017 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Deregistration Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Deregistration Status: 32-bit integer
The Deregistration Result Status field indicates the success or the
reason for failure of the deregistration.
Its values may be:
0 Successfully Deregistered
1 Error - Unknown
2 Error - Invalid Routing Context
3 Error - Permission Denied
4 Error - Not Registered
5 Error - ASP Currently Active for Routing Context
3.9.24. Local Routing Key Identifier
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0018 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Routing Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Local Routing Key Identifier field is a 32-bits unsigned integer.
The Identifier value is assigned by the ASP and is used to correlate
the response in a REG RSP message with the original registration
request. The Identifier value must remain unique until the REG RSP
message is received.
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3.10. SUA-Specific parameters
These TLV parameters are specific to the SUA protocol.
Parameter Name Parameter ID
============== ============
SS7 Hop Counter 0x0101
Source Address 0x0102
Destination Address 0x0103
Source Reference Number 0x0104
Destination Reference Number 0x0105
SCCP Cause 0x0106
Sequence Number 0x0107
Receive Sequence Number 0x0108
ASP Capabilities 0x0109
Credit 0x010A
Data 0x010B
User/Cause 0x010C
Network Appearance 0x010D
Routing Key 0x010E
DRN Label 0x010F
TID Label 0x0110
Address Range 0x0111
SMI 0x0112
Importance 0x0113
Message Priority 0x0114
Protocol Class 0x0115
Sequence Control 0x0116
Segmentation 0x0117
Congestion Level 0x0118
Destination/Source Address Sub-Parameters
===========================================
Global Title 0x8001
Point Code 0x8002
Subsystem Number 0x8003
IPv4 Address 0x8004
Hostname 0x8005
IPv6 Addresses 0x8006
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3.10.1. SS7 Hop counter
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SS7 Hop Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SS7 Hop Counter (3.18/Q.713)
The value of the SS7 Hop Counter is decremented with each global
title translation and is in the range 15 to 1.
3.10.2. Source Address
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Indicator | Address Indicator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Address parameter(s) /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following combinations of address parameters are valid:
- Global Title (e.g., E.164 number) + optional PC and/or SSN, SSN
may be zero, when routing is done on Global Title
- SSN (non-zero) + optional PC and/or Global Title, when routing is
done on PC + SSN. The PC is mandatory in the source address when
sending from SGP to ASP, and in the destination address when
sending from ASP to SGP to reach the SS7 SEP.
- Hostname + optional SSN, when routing is done by Hostname
- SSN (non-zero) and optional IP address (IPv4 or IPv6) when routing
is done on IP address + SSN
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3.10.2.1. Routing Indicator
The following values are valid for the routing indicator:
Reserved 0
Route on Global Title 1
Route on SSN + PC 2
Route on Hostname 3
Route on SSN + IP Address 4
The routing indicator determines which address parameters need to be
present in the address parameters field.
3.10.2.2. Address Indicator
This parameter is needed for interworking with SS7 networks. The
address indicator specifies what address parameters are actually
received in the SCCP address from the SS7 network, or are to be
populated in the SCCP address when the message is sent into the SS7
network. The value of the routing indicator needs to be taken into
account. It is used in the ASP to SG direction. For example, the PC
parameter is present in the destination address of the CLDT sent from
ASP->SG, but bit 2 is set to "0" meaning "do not populate this in the
SCCP called party address". The effect is that the SG only uses the
PC to populate the MTP routing label DPC field, but does not include
it in the SCCP called party address.
In the SG->ASP direction, the source address PC parameter is present
(PC of SS7 SEP). However, this may have been populated from the OPC
in the received MTP routing label, not from the PC field in the SCCP
calling party address. In this case, bit 2 = "0" denotes that. The
AI gives further instructions to the SG how and when to populate the
SCCP addresses; in the SG->ASP direction, the AI gives information to
the ASP as to what was actually present in the received SCCP
addresses.
The address indicator is coded as follows:
Bit 1 is used to indicate inclusion of the SSN
0 Do not include SSN when optional
1 Include SSN
Bit 2 is used to indicate inclusion of the PC
0 Do not include PC, regardless of the routing indicator
value
1 Include PC
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Bit 3 is used to indicate inclusion of the Global Title
0 Do not include GT when optional (routing indicator /= 1)
1 Include GT
The remaining bits are spare and SHOULD be coded zero, and MUST be
ignored by the receiver.
3.10.2.3. Global Title
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | GTI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| No. Digits | Trans. type | Num. Plan | Nature of Add |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Global Title Digits /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Number of Digits:
This is the number of digits contained in the Global Title.
GTI (Global Title Indicator, defined in chapter 3.4.2.3 of Q.713).
0000 Invalid
0001 Nature of Address is taken over. It is implicitly assumed
that the Translation Type = Unknown and Numbering Plan =
E.164 (value 1).
0010 This is most commonly used in North American networks.
The Translation Type implicitly determines Nature of
Address and Numbering Plan. This data can be configured
in the SG. The number of digits is always even and
determined by the SCCP address length.
0011 Numbering Plan and Translation Type are taken over. It is
implicitly assumed that the Nature of Address = Unknown.
0100 This format is used in international networks and most
commonly in networks outside North America. All
information to populate the source address is present in
the SCCP Address.
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Translation type:
0 Unknown
1 - 63 International services
64 - 127 Spare
128 - 254 National network specific
255 Reserved
Numbering Plan:
0 unknown
1 ISDN/telephony numbering plan (Recommendations E.163 and
E.164)
2 generic numbering plan
3 data numbering plan (Recommendation X.121)
4 telex numbering plan (Recommendation F.69)
5 maritime mobile numbering plan (Recommendations E.210,
E.211)
6 land mobile numbering plan (Recommendation E.212)
7 ISDN/mobile numbering plan (Recommendation E.214)
8 - 13 spare
14 private network or network-specific numbering plan
15 - 126 spare
127 reserved.
Nature of Address:
0 unknown
1 subscriber number
2 reserved for national use
3 national significant number
4 international number
5 - 255 Spare
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Global Title:
Octets contain a number of address signals and possibly filler as
shown:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|2 addr.|1 addr.|4 addr.|3 addr.|6 addr.|5 addr.|8 addr.|7 addr.|
| sig. | sig. | sig. | sig. | sig. | sig. | sig. | sig. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ............. |filler |N addr.| filler |
| |if req | sig. | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
All filler bits SHOULD be set to 0.
Address signals to be coded as defined in ITU-T Q.713 Section
3.4.2.3.1.
3.10.2.4. Point Code
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8002 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
See chapter 3.9.18 Affected Point Code for the layout of the Point
Code field.
3.10.2.5. Subsystem Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8003 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SSN value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The internationally standardized SSN values are described in chapter
3.4.2.2 of Q.713.
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3.10.2.6. IP Addresses
The IP address formats can use different tags. It should be noted
that if the source address is in a certain IP version, the
destination address should also be in the same IP version.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8004/0x8006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ IPv4 or IPv6 Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note: The tag value 0x8004 is for an IPv4 address and 0x8006 is
for IPv6.
3.10.2.7. Hostname
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x8005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Host Name /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Host Name: variable length
This field contains a host name in "host name syntax" per RFC 1123
Section 2.1 [1123]. The method for resolving the host name is out of
scope for this document.
Note: At least one null terminator is included in the Host Name
string and must be included in the length.
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3.10.3. Destination Address
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Indicator | Address Indicator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Address Parameter(s) /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of this parameter is identical to the Source Address
parameter.
3.10.4. Source Reference Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The source reference number is a 4 octet long integer. This is
allocated by the source SUA instance.
3.10.5. Destination Reference Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The destination reference number is a 4 octet long integer. This is
allocated by the destination SUA instance.
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3.10.6. SCCP Cause
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Cause Type | Cause Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This parameter bundles the SCCP parameters Release cause, Return
cause, Reset cause, Error cause and Refusal cause.
Cause Type can have the following values:
Return Cause 0x1
Refusal Cause 0x2
Release Cause 0x3
Reset Cause 0x4
Error Cause 0x5
Cause Value contains the specific cause value. Below gives examples
for ITU SCCP values. ANSI references can be found in ANSI T1.112.3
Cause value in Correspondence with Reference
SUA message SCCP parameter
------------------ ----------------- ---------
CLDR Return Cause ITU-T Q.713 Chap 3.12
COREF Refusal Cause ITU-T Q.713 Chap 3.15
RELRE Release Cause ITU-T Q.713 Chap 3.11
RESRE Reset Cause ITU-T Q.713 Chap 3.13
ERR Error Cause ITU-T Q.713 Chap 3.14
3.10.7. Sequence Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Rec Seq Num|M| Sent Seq Num |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This parameter is used to indicate whether "more" data will follow in
subsequent CODT messages, and/or to number each CODT message
sequentially for the purpose of flow control. It contains the
received as well as the sent sequence number, P(R) and P(S) in Q.713,
chapters 3.7 and 3.9.
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As such it can also be used to acknowledge the receipt of data
transfers from the peer in case of protocol class 3.
Sent Sequence Number is one octet and is coded as follows:
Bits 2-8 are used to indicate the Send Sequence Number P(S).
Bit 1 (LSB) of octet 1 is spare.
Received Sequence Number is one octet, and is coded as follows:
Bits 2-8 are used to indicate the Received Sequence Number
P(R).
Bit 1 (LSB) is used for the more data indication, as follows:
0 no more data
1 more data
3.10.8. Receive Sequence Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0108 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Rec Seq Num |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This parameter is used exclusively for protocol class 3 in the data
acknowledgement message to indicate the lower edge of the receiving
window. See Q.713, chapter 3.9.
It is a 1 octet long integer coded as follows:
Bits 8-2 are used to indicate the Received Sequence Number P(R).
Bit 1 is spare.
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3.10.9. ASP Capabilities
This parameter is used so that the ASP can report its capabilities
regarding SUA for supporting different protocol classes and
interworking scenarios.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0109 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |0 0 0 0|a|b|c|d| Interworking |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flags
a - Protocol Class 3
b - Protocol Class 2
c - Protocol Class 1
d - Protocol Class 0
It is mandatory to support at least Protocol Class 0.
Interworking
Values
0x0 indicates no interworking with SS7 Networks.
0x1 indicates IP Signalling Endpoint (ASP), interworking with SS7
networks.
0x2 indicates Signalling Gateway.
0x3 indicates relay node support.
3.10.10. Credit
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length of the credit field is one octet. See ITU-T Q.713 Chapter
3.10. The parameter is used for protocol class 3 exclusively.
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3.10.11. Data
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010b | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Data parameter field contains the SS7 SCCP-User application
message, for example an INAP/TCAP message.
3.10.12. User/Cause
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010c | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause | User |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"User" is coded to that SCCP's SI value. There may be several SCCP's
at a given point code, each with different SI values, although
normally there is only one with SI = 3.
Cause may take the following values
0 remote SCCP unavailable, reason unknown;
1 remote SCCP unequipped;
2 remote SCCP inaccessible;
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3.10.13. Network Appearance
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010D | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Network Appearance field: 32-bits (unsigned integer)
The Network Appearance field identifies the SS7 network context
for the Routing Key. The Network Appearance value is of local
significance only, coordinated between the SG and ASP. Therefore,
in the case where the ASP is connected to more than one SG, the
same SS7 Network context may be identified by different Network
Appearance values depending upon to which SG the ASP is
registering.
In the Routing Key, the Network Appearance identifies the SS7
Point Code and Global Title Translation Type format used, and the
SCCP and possibly the SCCP-User protocol (type, variant and
version) used within the specific SS7 network.
3.10.14. Routing Key
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010E | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0018 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Routing Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ Key parameter(s) \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Local Routing Key Identifier field: 32-bits (unsigned integer)
Key field: variable
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The Key field contains the following parameters:
Parameter
Traffic Mode Type Optional
Network Appearance Optional *1
Source Address Optional
Destination Address Optional
Address Range Optional
Note 1: The Network Appearance parameter must be included in the
Routing Key when the ASP is able to register in multiple
SS7 Network contexts.
3.10.15. DRN Label
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010F | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| start | end | label value |
+---------------+---------------+-------------------------------+
The Start parameter is the start position of label, between 0 (LSB)
and 23 (MSB).
The End parameter is the end position of label, between 0 (LSB) and
23 (MSB).
Label value is a 16-bit integer, which is unique across an AS.
3.10.16. TID Label
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0110 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| start | end | label value |
+---------------+---------------+-------------------------------+
The Start parameter is the start position of label, between 0 (LSB)
and 31 (MSB).
The End parameter is the end position of label, between 0 (LSB) and
31 (MSB).
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Label value is a 16-bit integer, which is unique across an AS.
3.10.17. Address Range
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0111 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ Address parameter(s) \
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Address field:
The Address field the following parameters:
Parameter
Source Address Optional *1
Destination Address Optional *1
Note 1: The Address field must contain pairs of Source Addresses
or pairs of Destination Addresses but MUST NOT mix Source
Addresses with Destination Addresses in the same Address
field.
3.10.18. SMI
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0112 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SMI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subsystem Multiplicity Indicator (SMI) can have the following
values:
0x00 Reserved/Unknown
0x01 Solitary
0x02 Duplicated
0x03 Triplicated
0x04 Quadruplicated
0xff Unspecified
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3.10.19. Importance
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0113 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Importance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Importance (3.19/Q.713)
Possible values of the Importance Parameter are between 0 and 7,
where the value of 0 indicates the least important and 7 indicates
the most important.
3.10.20. Message Priority (or Priority)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0114 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Msg Priority |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Priority
Priority value ranges from 0 to 3. If the Priority value has not
been specified by the SCCP user, it should be set to 0xFF. The SG
MAY take the priority into account for determining the MTP message
priority. In the all-IP case, this parameter MAY be used.
The Message Priority parameter is optional in the CLDT, CLDR, CORE,
COAK and CODT messages. However, for networks, which support Message
Priority (e.g., ANSI), this parameter MUST be included but it is not
required for those which don't (e.g., International).
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3.10.21. Protocol Class
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0115 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Protocol Cl. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protocol class (3.6/Q.713)
Bits 1-2 indicate the protocol class.
Value Description
0 Class 0 (connectionless service)
1 Class 1 (connectionless service)
2 Class 2 (connection-oriented service)
3 Class 3 (connection-oriented service)
Bit 8 indicates the use of the return on error procedure.
Value Description
0x0 No special options
0x1 Return message on error
Bits 3-7 are spare and SHOULD be coded zero, and MUST be
ignored by the receiver.
3.10.22. Sequence Control
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0116 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Control |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Sequence Control (6.2.2.2.2/Q.711)
The field is coded with the value of the sequence control parameter
associated with a group of messages and are chosen so as to ensure
proper loadsharing of message groups over SLS values while ensuring
that sequence control values within message groups have the sequence
control value coded with the same value as the initial message of the
message group.
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3.10.23. Segmentation
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0117 | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| first/remain | Segmentation Reference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The first/remaining segments field is formatted as follows: bit 8
(MSB): indicates whether this is the first segment (1) or not (0)
bits 1-7: indicate the number of remaining segments, value between 0
and 15
The field would thus be coded 1000 0000 (first, no remaining
segments) for a unsegmented CLDT.
The segmentation reference field is a 3 byte integer, assigned by the
ASP.
3.10.24. Congestion Level
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0118 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Congestion Level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Congestion Level field: 8-bits (unsigned integer)
The Congestion Level field contains the level at which congestion has
occurred.
When the Congestion Level parameter is included in a SCON message
that corresponds to an N-PCSTATE primitive, the Congestion Level
field indicates the MTP congestion level experienced by the local or
affected signalling point as indicated by the Affected Point Code(s)
also in the SCON message. In this case, valid values for the
Congestion Level field are as follows:
0 No Congestion or Undefined
1 Congestion Level 1
2 Congestion Level 2
3 Congestion Level 3
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When the Congestion Level parameter is included in a SCON message
that corresponds to an N-STATE primitive, the Congestion Level field
indicates the SCCP restricted importance level experienced by the
local or affected subsystem as indicated by the Affected Point Code
and Subsystem Number also in the SCON message. In this case, valid
values for the Congestion Level field range from 0 to 7, where 0
indicates the least congested and 7 indicates the most congested
subsystem.
4. Procedures
The SUA layer needs to respond to various local primitives it
receives from other layers as well as the messages that it receives
from the peer SUA layer. This section describes the SUA procedures
in response to these events.
4.1. Procedures to Support the SUA-User Layer
4.1.1. Receipt of Primitives from SCCP
When an SCCP Subsystem Management (SCMG) message is received from the
SS7 network, the SGP needs to determine whether there are concerned
Application Servers interested in subsystem status changes. The SUA
management function is informed with the N-State or N-Coord primitive
upon which it formats and transfers the applicable SNMM message to
the list of concerned ASPs using stream ID "0".
When MTP-3 Management indications are received (MTP-PAUSE, MTP-
RESUME, MTP-STATUS), SCCP Subsystem Management determines whether
there are concerned local SCCP-users. When these local SCCP-users
are in fact Application Servers, serviced by ASPs, SUA management is
informed with the N-PCSTATE indication primitive upon which it
formats and transfers the applicable SNM message (DUNA, DAVA, DRST or
SCON) to the list of concerned ASPs using stream ID "0".
The SUA message distribution function determines the Application
Server (AS) based on comparing the information in the N-UNITDATA
request primitive with a provisioned Routing Key.
From the list of ASPs within the AS table, an ASP in the ASP-ACTIVE
state is selected and a DATA message is constructed and issued on the
corresponding SCTP association. If more than one ASP is in the ASP-
ACTIVE state (i.e., traffic is to be load-shared across more than one
ASP), one of the ASPs in the ASP_ACTIVE state is selected from the
list. If the ASPs are in Broadcast Mode, all active ASPs will be
selected and the message sent to each of the active ASPs. The
selection algorithm is implementation dependent but could, for
example, be round robin or based on the SLS. The appropriate
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selection algorithm must be chosen carefully as it is dependent on
application assumptions and understanding of the degree of state
coordination between the ASP_ACTIVE ASPs in the AS.
In addition, the message needs to be sent on the appropriate SCTP
stream, again taking care to meet the message sequencing needs of the
signalling application. DATA messages MUST be sent on an SCTP stream
other than stream '0' when there is more than one stream.
When there is no Routing Key match, or only a partial match, for an
incoming SS7 message, a default treatment MAY be specified. Possible
solutions are to provide a default Application Server at the SGP that
directs all unallocated traffic to a (set of) default ASP(s), or to
drop the message and provide a notification to Layer Management in an
M-ERROR indication primitive. The treatment of unallocated traffic
is implementation dependent.
4.2. Receipt of Primitives from the Layer Management
On receiving primitives from the local Layer Management, the SUA
layer will take the requested action and provide an appropriate
response primitive to Layer Management.
An M-SCTP_ESTABLISH request primitive from Layer Management at an ASP
or IPSP will initiate the establishment of an SCTP association. The
SUA layer will attempt to establish an SCTP association with the
remote SUA peer by sending an SCTP-ASSOCIATE primitive to the local
SCTP layer.
When an SCTP association has been successfully established, the SCTP
will send an SCTP-COMMUNICATION_UP notification primitive to the
local SUA layer. At the ASP or IPSP that initiated the request, the
SUA layer will send an M-SCTP_ESTABLISH confirm primitive to Layer
Management when the association setup is complete. At the peer SUA
layer, an M-SCTP_ESTABLISH indication primitive is sent to Layer
Management upon successful completion of an incoming SCTP association
setup.
An M-SCTP_RELEASE request primitive from Layer Management initiates
the shutdown of an SCTP association. The SUA layer accomplishes a
graceful shutdown of the SCTP association by sending an SCTP-SHUTDOWN
primitive to the SCTP layer.
When the graceful shutdown of the SCTP association has been
accomplished, the SCTP layer returns an SCTP-SHUTDOWN_COMPLETE
notification primitive to the local SUA layer. At the SUA Layer that
initiated the request, the SUA layer will send an M-SCTP_RELEASE
confirm primitive to Layer Management when the association shutdown
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is complete. At the peer SUA Layer, an M-SCTP_RELEASE indication
primitive is sent to Layer Management upon abort or successful
shutdown of an SCTP association.
An M-SCTP_STATUS request primitive supports a Layer Management query
of the local status of a particular SCTP association. The SUA layer
simply maps the M-SCTP_STATUS request primitive to an SCTP-STATUS
primitive to the SCTP layer. When the SCTP responds, the SUA layer
maps the association status information to an M-SCTP_STATUS confirm
primitive. No peer protocol is invoked.
Similar LM-to-SUA-to-SCTP and/or SCTP-to-SUA-to-LM primitive mappings
can be described for the various other SCTP Upper Layer primitives in
RFC 2960 [2960] such as INITIALIZE, SET PRIMARY, CHANGE HEARTBEAT,
REQUEST HEARTBEAT, GET SRTT REPORT, SET FAILURE THRESHOLD, SET
PROTOCOL PARAMETERS, DESTROY SCTP INSTANCE, SEND FAILURE, AND NETWORK
STATUS CHANGE. Alternatively, these SCTP Upper Layer primitives (and
Status as well) can be considered for modeling purposes as a Layer
Management interaction directly with the SCTP Layer.
M-NOTIFY indication and M-ERROR indication primitives indicate to
Layer Management the notification or error information contained in a
received SUA Notify or Error message respectively. These indications
can also be generated based on local SUA events.
An M-ASP_STATUS request primitive supports a Layer Management query
of the status of a particular local or remote ASP. The SUA layer
responds with the status in an M-ASP_STATUS confirm primitive. No
SUA peer protocol is invoked. An M-AS_STATUS request supports a
Layer Management query of the status of a particular AS. The SUA
responds with an M-AS_STATUS confirm primitive. No SUA peer protocol
is invoked.
M-ASP_UP request, M-ASP_DOWN request, M-ASP_ACTIVE request and M-
ASP_INACTIVE request primitives allow Layer Management at an ASP to
initiate state changes. Upon successful completion, a corresponding
confirm primitive is provided by the SUA layer to Layer Management.
If an invocation is unsuccessful, an Error indication primitive is
provided in the primitive. These requests result in outgoing ASP Up,
ASP Down, ASP Active and ASP Inactive messages to the remote SUA peer
at an SGP or IPSP.
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4.2.1. Receipt of SUA Peer Management Messages
Upon successful state changes resulting from reception of ASP Up, ASP
Down, ASP Active and ASP Inactive messages from a peer SUA, the SUA
layer MAY invoke corresponding M-ASP_UP, M-ASP_DOWN, M-ASP_ACTIVE and
M-ASP_INACTIVE, M-AS_ACTIVE, M-AS_INACTIVE, and M-AS_DOWN indication
primitives to the local Layer Management.
M-NOTIFY indication and M-ERROR indication primitives indicate to
Layer Management the notification or error information contained in a
received SUA Notify or Error message. These indications can also be
generated based on local SUA events.
All non-Transfer and non-SSNM messages, except BEAT and BEAT Ack,
SHOULD be sent with sequenced delivery to ensure ordering. All non-
Transfer messages, with the exception of ASPTM, BEAT and BEAT Ack
messages SHOULD be sent on SCTP stream '0'. ASPTM messages MAY be
sent on one of the streams used to carry data traffic related to the
Routing Context(s), to minimize possible message loss. BEAT and BEAT
Ack messages MAY be sent using out-of-order delivery, and MAY be sent
on any stream.
4.3. AS and ASP State Maintenance
The SUA layer on the SGP maintains the state of each remote ASP, in
each Application Server that the ASP is configured to receive
traffic, as input to the SUA message distribution function.
Similarly, where IPSPs use SUA in a point-to-point fashion, the SUA
layer in an IPSP maintains the state of remote IPSPs.
Two IPSP models are defined with regards to the number of messages
that are needed to a IPSP state change. They are defined as follows:
1. IPSP Single Exchange (SE) model. Only a single exchange of ASPTM
or ASPSM messages is needed to change the IPSP state. This means
that a set of request from one end and acknowledge from the other
will be enough.
2. IPSP Double Exchange (DE) model. Both IPSPs have to send request
messages and both IPSPs have to acknowledge the request messages
from the other end. This results in a double exchange of ASPTM
and ASPSM message, one from each end. This configuration supports
dynamic routing key configuration by using RKM messages in the
same way as ASP-SGP scenario.
To ensure interoperability, an SUA implementation supporting IPSP
communication MUST support IPSP SE model and MAY implement IPSP DE
model.
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In section 4.3.1: ASP/IPSP States, only the SGP-ASP and the IPSP SE
scenarios are described. For the IPSP DE model, both IPSPs MUST
follow the SGP side of the SGP-ASP procedures.
In section 4.3.2, only the SGP-ASP scenario is described. All of the
procedures referring to an AS served by ASPs are also applicable to
ASs served by IPSPs.
In section 4.3.3, only the Management procedures for the SGP-ASP
scenario are described. The corresponding Management procedures for
IPSPs are directly inferred.
The remaining sections contain specific IPSP Considerations
subsections.
4.3.1. ASP States
The state of each remote ASP/IPSP, in each AS that it is configured
to operate, is maintained in the peer SUA layer (i.e., in the SGP or
peer IPSP, respectively). The state of a particular ASP/IPSP in a
particular AS changes due to events. The events include:
* Reception of messages from the peer SUA layer at the ASP/IPSP;
* Reception of some messages from the peer SUA layer at other
ASPs/IPSPs in the AS (e.g., ASP Active message indicating
"Override");
* Reception of indications from the SCTP layer; or
* Local Management intervention.
The ASP/IPSP state transition diagram is shown in Figure 1. The
possible states of an ASP/IPSP are:
ASP-DOWN: The remote SUA peer at the ASP/IPSP is unavailable and/or
the related SCTP association is down. Initially all ASPs/IPSPs will
be in this state. An ASP/IPSP in this state SHOULD NOT be sent any
SUA messages, with the exception of Heartbeat, ASP Down Ack and Error
messages.
ASP-INACTIVE: The remote SUA peer at the ASP/IPSP is available (and
the related SCTP association is up) but application traffic is
stopped. In this state the ASP/IPSP SHOULD NOT be sent any DATA or
SSNM messages for the AS for which the ASP/IPSP is inactive.
ASP-ACTIVE: The remote SUA peer at the ASP/IPSP is available and
application traffic is active (for a particular Routing Context or
set of Routing Contexts).
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Figure 1: ASP/IPSP State Transition Diagram, per AS
+--------------+
| |
+----------------------| ASP-ACTIVE |
| Other ASP/ +-------| |
| IPSP in AS | +--------------+
| Overrides | ^ |
| | ASPAC/ | | ASPIA/
| |[ASPAC-Ack]| | [ASPIA-Ack]
| | | v
| | +--------------+
| | | |
| +------>| ASP-INACTIVE |
| | |
| +--------------+
| ^ |
ASPDN/ | | | ASPDN /
[ASPDN-Ack/]| ASPUP/ | | [ASPDN-Ack /]
SCTP CDI/ | [ASPUP-Ack] | | SCTP CDI/
SCTP RI | | | SCTP RI
| | v
| +--------------+
| | |
+--------------------->| ASP-DOWN |
| |
+--------------+
The transitions in brackets are just valid for the IPSP SE model
communication while the rest are valid for both ASPs and IPSPs.
SCTP CDI: The SCTP CDI denotes the local SCTP layer's Communication
Down Indication to the Upper Layer Protocol (SUA) on an SGP. The
local SCTP layer will send this indication when it detects the loss
of connectivity to the ASP's peer SCTP layer. SCTP CDI is understood
as either a SHUTDOWN_COMPLETE notification or COMMUNICATION_LOST
notification from the SCTP layer.
SCTP RI: The local SCTP layer's Restart indication to the upper layer
protocol (SUA) on an SG. The local SCTP will send this indication
when it detects a restart from the ASP's peer SCTP layer.
4.3.2. AS States
The state of the AS is maintained in the SUA layer on the SGP. The
state of an AS changes due to events. These events include:
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* ASP state transitions
* Recovery timer triggers
The possible states of an AS are:
AS-DOWN: The Application Server is unavailable. This state
implies that all related ASPs are in the ASP-DOWN state
for this AS. Initially the AS will be in this state.
An Application Server is in the AS-DOWN state before it
can be removed from a configuration.
AS-INACTIVE: The Application Server is available but no application
traffic is active (i.e., one or more related ASPs are in
the ASP-INACTIVE state, but none in the ASP-ACTIVE
state). The recovery timer T(r) is not running or has
expired.
AS-ACTIVE : The Application Server is available and application
traffic is active. This state implies that at least one
ASP is in the ASP-ACTIVE state.
AS-PENDING: An active ASP has transitioned to ASP-INACTIVE or ASP-
DOWN and it was the last remaining active ASP in the AS.
A recovery timer T(r) SHOULD be started and all incoming
signalling messages SHOULD be queued by the SGP. If an
ASP becomes ASP-ACTIVE before T(r) expires, the AS is
moved to the AS-ACTIVE state and all the queued messages
will be sent to the ASP.
If T(r) expires before an ASP becomes ASP-ACTIVE, and the SGP has no
alternative, the SGP may stop queueing messages and discard all
previously queued messages. The AS will move to the AS-INACTIVE
state if at least one ASP is in ASP-INACTIVE state, otherwise it will
move to AS-DOWN state.
Figure 2 shows an example AS state machine for the case where the
AS/ASP data is provisioned. For other cases where the AS/ASP
configuration data is created dynamically, there would be differences
in the state machine, especially at creation of the AS.
For example, where the AS/ASP configuration data is not created until
Registration of the first ASP, the AS-INACTIVE state is entered
directly upon the first successful REG REQ from an ASP. Another
example is where the AS/ASP configuration data is not created until
the first ASP successfully enters the ASP-ACTIVE state. In this case
the AS-ACTIVE state is entered directly.
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Figure 2: AS State Transition Diagram
+----------+ one ASP trans to ACTIVE +-------------+
| AS- |---------------------------->| AS- |
| INACTIVE | | ACTIVE |
| |<--- | |
+----------+ \ +-------------+
^ | \ Tr Expiry, ^ |
| | \ at least one | |
| | \ ASP in ASP-INACTIVE | |
| | \ | |
| | \ | |
| | \ | |
one ASP | | all ASP \ one ASP | | Last ACTIVE
trans | | trans to \ trans to | | ASP trans to
to | | ASP-DOWN -------\ ASP- | | ASP-INACTIVE
ASP- | | \ ACTIVE | | or ASP-DOWN
INACTIVE| | \ | | (start Tr)
| | \ | |
| | \ | |
| v \ | v
+----------+ \ +-------------+
| | --| |
| AS-DOWN | | AS-PENDING |
| | | (queueing) |
| |<----------------------------| |
+----------+ Tr Expiry and no ASP +-------------+
in ASP-INACTIVE state
Tr = Recovery Timer
4.3.2.1. IPSP Considerations
The AS state diagram for the AS-SG case is applicable for IPSP
communication.
4.3.3. SUA Management Procedures for Primitives
Before the establishment of an SCTP association the ASP state at both
the SGP and ASP is assumed to be in the state ASP-DOWN.
Once the SCTP association is established (see Section 4.2.1) and
assuming that the local SUA-User is ready, the local SUA ASP
Maintenance (ASPM) function will initiate the relevant procedures,
using the ASP Up/ASP Down/ASP Active/ASP Inactive messages to convey
the ASP state to the SGP (see Section 4.3.4).
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If the SUA layer subsequently receives an SCTP-COMMUNICATION_DOWN or
SCTP-RESTART indication primitive from the underlying SCTP layer, it
will inform the Layer Management by invoking the M-SCTP_STATUS
indication primitive. The state of the ASP will be moved to ASP-
DOWN.
In the case of SCTP-COMMUNICATION_DOWN, the SCTP client MAY try to
reestablish the SCTP association. This MAY be done by the SUA layer
automatically, or Layer Management MAY reestablish using the M-
SCTP_ESTABLISH request primitive.
In the case of an SCTP-RESTART indication at an ASP, the ASP is now
considered by its SUA peer to be in the ASP-DOWN state. The ASP, if
it is to recover, must begin any recovery with the ASP-Up procedure.
4.3.4. ASPM Procedures for Peer-to-Peer Messages
4.3.4.1. ASP Up Procedures
After an ASP has successfully established an SCTP association to an
SGP, the SGP waits for the ASP to send an ASP Up message, indicating
that the ASP SUA peer is available. The ASP is always the initiator
of the ASP Up message. This action MAY be initiated at the ASP by an
M-ASP_UP request primitive from Layer Management or MAY be initiated
automatically by an SUA management function.
When an ASP Up message is received at an SGP and internally the
remote ASP is in the ASP-DOWN state and not considered locked-out for
local management reasons, the SGP marks the remote ASP in the state
ASP-INACTIVE and informs Layer Management with an M-ASP_Up indication
primitive. If the SGP is aware, via current configuration data,
which Application Servers the ASP is configured to operate in, the
SGP updates the ASP state to ASP-INACTIVE in each AS that it is a
member.
Alternatively, the SGP may move the ASP into a pool of Inactive ASPs
available for future configuration within Application Server(s),
determined in a subsequent Registration Request or ASP Active
procedure. If the ASP Up message contains an ASP Identifier, the SGP
should save the ASP Identifier for that ASP. The SGP MUST send an
ASP Up Ack message in response to a received ASP Up message even if
the ASP is already marked as ASP-INACTIVE at the SGP.
If for any local reason (e.g., management lock-out) the SGP cannot
respond with an ASP Up Ack message, the SGP responds to an ASP Up
message with an Error message with Reason "Refused - Management
Blocking".
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At the ASP, the ASP Up Ack message received is not acknowledged.
Layer Management is informed with an M-ASP_UP confirm primitive.
When the ASP sends an ASP Up message it starts timer T(ack). If the
ASP does not receive a response to an ASP Up message within T(ack),
the ASP MAY restart T(ack) and resend ASP Up messages until it
receives an ASP Up Ack message. T(ack) is provisioned, with a
default of 2 seconds. Alternatively, retransmission of ASP Up
messages MAY be put under control of Layer Management. In this
method, expiry of T(ack) results in an M-ASP_UP confirm primitive
carrying a negative indication.
The ASP must wait for the ASP Up Ack message before sending any other
SUA messages (e.g., ASP Active or REG REQ). If the SGP receives any
other SUA messages before ASPUP message is received (other than ASPDN
- see section 4.3.4.2), the SGP SHOULD discard them.
If an ASP Up message is received and internally the remote ASP is in
the ASP-ACTIVE state, an ASP Up Ack message is returned, as well as
an Error message ("Unexpected Message), and the remote ASP state is
changed to ASP-INACTIVE in all relevant Application Servers.
If an ASP Up message is received and internally the remote ASP is
already in the ASP-INACTIVE state, an ASP Up Ack message is returned
and no further action is taken.
4.3.4.1.1. SUA Version Control
If an ASP Up message with an unsupported version is received, the
receiving end responds with an Error message, indicating the version
the receiving node supports and notifies Layer Management.
This is useful when protocol version upgrades are being performed in
a network. A node upgraded to a newer version should support the
older versions used on other nodes it is communicating with. Because
ASPs initiate the ASP Up procedure it is assumed that the Error
message would normally come from the SGP.
4.3.4.1.2. IPSP Considerations
An IPSP may be considered in the ASP-INACTIVE state after and ASPUP
or ASPUP Ack has been received from it. An IPSP can be considered in
the ASP-DOWN state after an ASPDN or ASPDN Ack has been received from
it. The IPSP may inform Layer Management of the change in state of
the remote IPSP using M-ASP_UP or M-ASP_DN indication or confirmation
primitives.
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Alternatively, when using IPSP DE model, an interchange of ASP Up
messages from each end MUST be performed. Four messages are needed
for completion.
If for any local reason (e.g., management lock-out) and IPSP cannot
respond to an ASP Up message with an ASP Up Ack message, it responds
to an ASP Up message with an Error message with Reason "Refused -
Management Blocking" and leaves the remote IPSP in the ASP-DOWN
state.
4.3.4.2. ASP Down Procedures
The ASP will send an ASP Down message to an SGP when the ASP wishes
to be removed from service in all Application Servers that it is a
member and no longer receive any Connectionless or Connection -
Oriented, SSNM or ASPTM messages. This action MAY be initiated at
the ASP by an M-ASP_DOWN request primitive from Layer Management or
MAY be initiated automatically by an SUA management function.
Whether the ASP is permanently removed from any AS is a function of
configuration management. In the case where the ASP previously used
the Registration procedures (see Section 4.4.1) to register within
Application Servers but has not deregistered from all of them prior
to sending the ASP Down message, the SGP MUST consider the ASP as
deregistered in all Application Servers that it is still a member.
The SGP marks the ASP as ASP-DOWN, informs Layer Management with an
M-ASP_Down indication primitive, and returns an ASP Down Ack message
to the ASP.
The SGP MUST send an ASP Down Ack message in response to a received
ASP Down message from the ASP even if the ASP is already marked as
ASP-DOWN at the SGP.
At the ASP, the ASP Down Ack message received is not acknowledged.
Layer Management is informed with an M-ASP_DOWN confirm primitive. If
the ASP receives an ASP Down Ack without having sent an ASP Down
message, the ASP should now consider itself as in the ASP-DOWN state.
If the ASP was previously in the ASP-ACTIVE or ASP_INACTIVE state,
the ASP should then initiate procedures to return itself to its
previous state.
When the ASP sends an ASP Down message it starts timer T(ack). If
the ASP does not receive a response to an ASP Down message within
T(ack), the ASP MAY restart T(ack) and resend ASP Down messages until
it receives an ASP Down Ack message. T(ack) is provisioned, with a
default of 2 seconds. Alternatively, retransmission of ASP Down
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messages MAY be put under control of Layer Management. In this
method, expiry of T(ack) results in an M-ASP_DOWN confirm primitive
carrying a negative indication.
4.3.4.3. ASP Active Procedures
Anytime after the ASP has received an ASP Up Ack message from the SGP
or IPSP, the ASP MAY send an ASP Active message to the SGP indicating
that the ASP is ready to start processing traffic. This action MAY
be initiated at the ASP by an M-ASP_ACTIVE request primitive from
Layer Management or MAY be initiated automatically by an SUA
management function. In the case where an ASP wishes to process the
traffic for more than one Application Server across a common SCTP
association, the ASP Active message(s) SHOULD contain a list of one
or more Routing Contexts to indicate for which Application Servers
the ASP Active message applies. It is not necessary for the ASP to
include all Routing Contexts of interest in a single ASP Active
message, thus requesting to become active in all Routing Contexts at
the same time. Multiple ASP Active messages MAY be used to activate
within the Application Servers independently, or in sets. In the
case where an ASP Active message does not contain a Routing Context
parameter, the receiver must know, via configuration data, which
Application Server(s) the ASP is a member.
For the Application Servers that the ASP can be successfully
activated, the SGP or IPSP responds with one or more ASP Active Ack
messages, including the associated Routing Context(s) and reflecting
any Traffic Mode Type value present in the related ASP Active
message. The Routing Context parameter MUST be included in the ASP
Active Ack message(s) if the received ASP Active message contained
any Routing Contexts. Depending on any Traffic Mode Type request in
the ASP Active message, or local configuration data if there is no
request, the SGP moves the ASP to the correct ASP traffic state
within the associated Application Server(s). Layer Management is
informed with an M-ASP_Active indication. If the SGP or IPSP
receives any Data messages before an ASP Active message is received,
the SGP or IPSP MAY discard them. By sending an ASP Active Ack
message, the SGP or IPSP is now ready to receive and send traffic for
the related Routing Context(s). The ASP SHOULD NOT send Data or SSNM
messages for the related Routing Context(s) before receiving an ASP
Active Ack message, or it will risk message loss.
Multiple ASP Active Ack messages MAY be used in response to an ASP
Active message containing multiple Routing Contexts, allowing the SGP
or IPSP to independently acknowledge the ASP Active message for
different (sets of) Routing Contexts. The SGP or IPSP MUST send an
Error message ("Invalid Routing Context") for each Routing Context
value that cannot be successfully activated.
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In the case where an "out-of-the-blue" ASP Active message is received
(i.e., the ASP has not registered with the SG or the SG has no static
configuration data for the ASP), the message MAY be silently
discarded.
The SGP MUST send an ASP Active Ack message in response to a received
ASP Active message from the ASP, if the ASP is already marked in the
ASP-ACTIVE state at the SGP.
At the ASP, the ASP Active Ack message received is not acknowledged.
Layer Management is informed with an M-ASP_ACTIVE confirm primitive.
It is possible for the ASP to receive Data message(s) before the ASP
Active Ack message as the ASP Active Ack and Data messages from an SG
or IPSP may be sent on different SCTP streams. Message loss is
possible, as the ASP does not consider itself in the ASP-ACTIVE state
until reception of the ASP Active Ack message.
When the ASP sends an ASP Active message it starts timer T(ack). If
the ASP does not receive a response to an ASP Active message within
T(ack), the ASP MAY restart T(ack) and resend ASP Active messages
until it receives an ASP Active Ack message. T(ack) is provisioned,
with a default of 2 seconds. Alternatively, retransmission of ASP
Active messages MAY be put under control of Layer Management. In
this method, expiry of T(ack) results in an M-ASP_ACTIVE confirm
primitive carrying a negative indication.
There are three modes of Application Server traffic handling in the
SGP SUA layer: Override, Loadshare and Broadcast. When included, the
Traffic Mode Type parameter in the ASP Active message indicates the
traffic-handling mode to be used in a particular Application Server.
If the SGP determines that the mode indicated in an ASP Active
message is unsupported or incompatible with the mode currently
configured for the AS, the SGP responds with an Error message
("Unsupported / Invalid Traffic Handling Mode"). If the traffic-
handling mode of the Application Server is not already known via
configuration data, then the traffic-handling mode indicated in the
first ASP Active message causing the transition of the Application
Server state to AS-ACTIVE MAY be used to set the mode.
In the case of an Override mode AS, reception of an ASP Active
message at an SGP causes the (re)direction of all traffic for the AS
to the ASP that sent the ASP Active message. Any previously active
ASP in the AS is now considered to be in state ASP-INACTIVE and
SHOULD no longer receive traffic from the SGP within the AS. The SGP
or IPSP then MUST send a Notify message ("Alternate ASP Active") to
the previously active ASP in the AS, and SHOULD stop traffic to/from
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that ASP. The ASP receiving this Notify MUST consider itself now in
the ASP-INACTIVE state, if it is not already aware of this via
inter-ASP communication with the Overriding ASP.
In the case of a Loadshare mode AS, reception of an ASP Active
message at an SGP or IPSP causes the direction of traffic to the ASP
sending the ASP Active message, in addition to all the other ASPs
that are currently active in the AS. The algorithm at the SGP for
loadsharing traffic within an AS to all the active ASPs is
implementation dependent. The algorithm could, for example, be round
robin or based on information in the Data message (e.g., the SLS or
SSN).
An SGP or IPSP, upon reception of an ASP Active message for the first
ASP in a Loadshare AS, MAY choose not to direct traffic to a newly
active ASP until it determines that there are sufficient resources to
handle the expected load (e.g., until there are "n" ASPs in state
ASP-ACTIVE in the AS).
All ASPs within a load-sharing mode AS must be able to process any
Data message received for the AS, to accommodate any potential fail-
over or rebalancing of the offered load.
In the case of a Broadcast mode AS, reception of an ASP Active
message at an SGP or IPSP causes the direction of traffic to the ASP
sending the ASP Active message, in addition to all the other ASPs
that are currently active in the AS. The algorithm at the SGP for
broadcasting traffic within an AS to all the active ASPs is a simple
broadcast algorithm, where every message is sent to each of the
active ASPs. An SGP or IPSP, upon reception of an ASP Active message
for the first ASP in a Broadcast AS, MAY choose not to direct traffic
to a newly active ASP until it determines that there are sufficient
resources to handle the expected load (e.g., until there are "n" ASPs
in state ASP-ACTIVE in the AS).
Whenever an ASP in a Broadcast mode AS becomes ASP-ACTIVE, the SGP
MUST tag the first DATA message broadcast in each traffic flow with a
unique Correlation Id parameter. The purpose of this Correlation Id
is to permit the newly active ASP to synchronize its processing of
traffic in each traffic flow with the other ASPs in the broadcast
group.
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4.3.4.3.1. IPSP Considerations
Either of the IPSPs can initiate communication. When an IPSP
receives an ASP Active, it should mark the peer as ASP-ACTIVE and
return an ASP Active Ack message. An ASP receiving an ASP Active Ack
message may mark the peer as ASP-Active, if it is not already in the
ASP-ACTIVE state.
Alternatively, when using IPSP DE model, an interchange of ASP Active
messages from each end MUST be performed. Four messages are needed
for completion.
4.3.4.4. ASP Inactive Procedures
When an ASP wishes to withdraw from receiving traffic within an AS,
or the ASP wants to initiate the process of deactivation, the ASP
sends an ASP Inactive message to the SGP or IPSP.
An ASP Inactive message MUST be always responded by the peer
(although other messages may be sent in the middle):
- If the corresponding RK is registered (statically or dynamically),
the peer should respond with an ASP Inactive Ack message.
- If the RK is not registered, or the RC information is not valid,
the peer must respond with an ERROR message with Error Code =
"Invalid Routing Context".
- If the RC is missing and its specification is needed according to
the used configuration, the peer must respond with an ERROR
message with Error Code = "No Configured AS for ASP".
The action of sending the ASP Inactive message MAY be initiated at
the ASP by an M-ASP_INACTIVE request primitive from Layer Management
or MAY be initiated automatically by an SUA management function. In
the case where an ASP is processing the traffic for more than one
Application Server across a common SCTP association, the ASP Inactive
message contains one or more Routing Contexts to indicate for which
Application Servers the ASP Inactive message applies.
In the case where an ASP Inactive message does not contain a Routing
Context parameter, the receiver must know, via configuration data,
which Application Servers the ASP is a member and move the ASP to the
ASP-INACTIVE state in each all Application Servers.
In the case of an Override mode AS, where another ASP has already
taken over the traffic within the AS with an ASP Active ("Override")
message, the ASP that sends the ASP Inactive message is already
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considered by the SGP to be in state ASP-INACTIVE. An ASP Inactive
Ack message is sent to the ASP, after ensuring that all traffic is
stopped to the ASP.
In the case of a Loadshare mode AS, the SGP moves the ASP to the
ASP-INACTIVE state and the AS traffic is reallocated across the
remaining ASPs in the state ASP-ACTIVE, as per the loadsharing
algorithm currently used within the AS. A Notify message
("Insufficient ASP resources active in AS") MAY be sent to all
inactive ASPs, if required. An ASP Inactive Ack message is sent to
the ASP after all traffic is halted and Layer Management is informed
with an M-ASP_INACTIVE indication primitive.
In the case of a Broadcast mode AS, the SGP moves the ASP to the
ASP-INACTIVE state and the AS traffic is broadcast only to the
remaining ASPs in the state ASP-ACTIVE. A Notify message
("Insufficient ASP resources active in AS") MAY be sent to all
inactive ASPs, if required. An ASP Inactive Ack message is sent to
the ASP after all traffic is halted and Layer Management is informed
with an M-ASP_INACTIVE indication primitive.
Multiple ASP Inactive Ack messages MAY be used in response to an ASP
Inactive message containing multiple Routing Contexts, allowing the
SGP or IPSP to independently acknowledge for different (sets of)
Routing Contexts. The SGP or IPSP sends an Error message ("Invalid
Routing Context") message for each invalid or not configured Routing
Context value in a received ASP Inactive message.
The SGP MUST send an ASP Inactive Ack message in response to a
received ASP Inactive message from the ASP and the ASP is already
marked as ASP-INACTIVE at the SGP.
At the ASP, the ASP Inactive Ack message received is not
acknowledged. Layer Management is informed with an M-ASP_INACTIVE
confirm primitive. If the ASP receives an ASP Inactive Ack without
having sent an ASP Inactive message, the ASP should now consider
itself as in the ASP-INACTIVE state. If the ASP was previously in
the ASP-ACTIVE state, the ASP should then initiate procedures to
return itself to its previous state. When the ASP sends an ASP
Inactive message it starts timer T(ack). If the ASP does not receive
a response to an ASP Inactive message within T(ack), the ASP MAY
restart T(ack) and resend ASP Inactive messages until it receives an
ASP Inactive Ack message. T(ack) is provisioned, with a default of 2
seconds. Alternatively, retransmission of ASP Inactive messages MAY
be put under control of Layer Management. In this method, expiry of
T(ack) results in a M-ASP_Inactive confirm primitive carrying a
negative indication.
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If no other ASPs in the Application Server are in the state ASP-
ACTIVE, the SGP MUST send a Notify message ("AS-Pending") to all of
the ASPs in the AS which are in the state ASP-INACTIVE. The SGP
SHOULD start buffering the incoming messages for T(r) seconds, after
which messages MAY be discarded. T(r) is configurable by the network
operator. If the SGP receives an ASP Active message from an ASP in
the AS before expiry of T(r), the buffered traffic is directed to
that ASP and the timer is cancelled. If T(r) expires, the AS is
moved to the AS-INACTIVE state.
4.3.4.4.1. IPSP Considerations
An IPSP may be considered in the ASP-INACTIVE state by a remote IPSP
after an ASP Inactive or ASP Inactive Ack message has been received
from it.
Alternatively, when using IPSP DE model, an interchange of ASP
Inactive messages from each end MUST be performed. Four messages are
needed for completion.
4.3.4.5. Notify Procedures
A Notify message reflecting a change in the AS state MUST be sent to
all ASPs in the AS, except those in the ASP-DOWN state, with
appropriate Status Information and any ASP Identifier of the failed
ASP. At the ASP, Layer Management is informed with an M-NOTIFY
indication primitive. The Notify message must be sent whether the AS
state change was a result of an ASP failure or reception of an ASP
State management (ASPSM) / ASP Traffic Management (ASPTM) message.
In the second case, the Notify message MUST be sent after any ASP
State or Traffic Management related acknowledgement messages (e.g.,
ASP Up Ack, ASP Down Ack, ASP Active Ack, or ASP Inactive Ack).
In the case where a Notify ("AS-PENDING") message is sent by an SGP
that now has no ASPs active to service the traffic, or where a Notify
("Insufficient ASP resources active in AS") message MUST be sent in
the Loadshare or Broadcast mode, the Notify message does not
explicitly compel the ASP(s) receiving the message to become active.
The ASPs remain in control of what (and when) traffic action is
taken.
In the case where a Notify message does not contain a Routing Context
parameter, the receiver must know, via configuration data, of which
Application Servers the ASP is a member and take the appropriate
action in each AS.
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4.3.4.5.1. IPSP Considerations (NTFY)
Notify works in the same manner as in the SG-AS case. One of the
IPSPs can send this message to any remote IPSP that is not in the
ASP-DOWN state.
4.3.4.6. Heartbeat Procedures
The optional Heartbeat procedures MAY be used when operating over
transport layers that do not have their own heartbeat mechanism for
detecting loss of the transport association (i.e., other than SCTP).
Either SUA peer may optionally send Heartbeat messages periodically,
subject to a provisioned timer T(beat). Upon receiving a Heartbeat
message, the SUA peer MUST respond with a Heartbeat Ack message.
If no Heartbeat Ack message (or any other SUA message) is received
from the SUA peer within 2*T(beat), the remote SUA peer is considered
unavailable. Transmission of Heartbeat messages is stopped and the
signalling process SHOULD attempt to reestablish communication if it
is configured as the client for the disconnected SUA peer.
The Heartbeat message may optionally contain an opaque Heartbeat Data
parameter that MUST be echoed back unchanged in the related Heartbeat
Ack message. The sender, upon examining the contents of the returned
Heartbeat Ack message, MAY choose to consider the remote SUA peer as
unavailable. The contents/format of the Heartbeat Data parameter is
implementation-dependent and only of local interest to the original
sender. The contents may be used, for example, to support a
Heartbeat sequence algorithm (to detect missing Heartbeats), and/or a
timestamp mechanism (to evaluate delays).
Note: Heartbeat related events are not shown in Figure 2 "ASP state
transition diagram".
4.4. Routing Key Management Procedures
4.4.1. Registration
An ASP MAY dynamically register with an SGP as an ASP within an
Application Server using the REG REQ message. A Routing Key
parameter in the REG REQ message specifies the parameters associated
with the Routing Key.
The SGP examines the contents of the received Routing Key parameter
and compares it with the currently provisioned Routing Keys. If the
received Routing Key matches an existing SGP Routing Key entry, and
the ASP is not currently included in the list of ASPs for the related
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Application Server, the SGP MAY authorize the ASP to be added to the
AS. Or, if the Routing Key does not currently exist and the received
Routing Key data is valid and unique, an SGP supporting dynamic
configuration MAY authorize the creation of a new Routing Key and
related Application Server and add the ASP to the new AS. In either
case, the SGP returns a Registration Response message to the ASP,
containing the same Local-RK-Identifier as provided in the initial
request, and a Registration Result "Successfully Registered". A
unique Routing Context value assigned to the SGP Routing Key is
included. The method of Routing Context value assignment at the SGP
is implementation dependent but must be guaranteed to be unique for
each Application Server or Routing Key supported by the SGP. If the
SGP determines that the received Routing Key data is invalid, or
contains invalid parameter values, the SGP returns a Registration
Response message to the ASP, containing a Registration Result "Error
- Invalid Routing Key", "Error - Invalid DPC", "Error - Invalid
Network Appearance" as appropriate.
If the SGP does not support the registration procedure, the SGP
returns an Error message to the ASP, with an error code of
"Unsupported Message Type".
If the SGP determines that a unique Routing Key cannot be created,
the SGP returns a Registration Response message to the ASP, with a
Registration Status of "Error - Cannot Support Unique Routing". An
incoming signalling message received at an SGP should not match
against more than one Routing Key.
If the SGP does not authorize the registration request, the SGP
returns a REG RSP message to the ASP containing the Registration
Result "Error - Permission Denied".
If an SGP determines that a received Routing Key does not currently
exist and the SGP does not support dynamic configuration, the SGP
returns a Registration Response message to the ASP, containing a
Registration Result "Error - Routing Key not Currently Provisioned".
If an SGP determines that a received Routing Key does not currently
exist and the SGP supports dynamic configuration but does not have
the capacity to add new Routing Key and Application Server entries,
the SGP returns a Registration Response message to the ASP,
containing a Registration Result "Error - Insufficient Resources".
If an SGP determines that one or more of the Routing Key parameters
are not supported for the purpose of creating new Routing Key
entries, the SGP returns a Registration Response message to the ASP,
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containing a Registration Result "Error - Unsupported RK parameter
field". This result MAY be used if, for example, the SGP does not
support RK Address parameter.
A Registration Response "Error - Unsupported Traffic Handling Mode"
is returned if the Routing Key in the REG REQ contains a Traffic
Handling Mode that is inconsistent with the presently configured mode
for the matching Application Server.
An ASP MAY register multiple Routing Keys at once by including a
number of Routing Key parameters in a single REG REQ message. The
SGP MAY respond to each registration request in a single REG RSP
message, indicating the success or failure result for each Routing
Key in a separate Registration Result parameter. Alternatively the
SGP MAY respond with multiple REG RSP messages, each with one or more
Registration Result parameters. The ASP uses the Local-RK-Identifier
parameter to correlate the requests with the responses.
An ASP MAY modify an existing Routing Key by including a Routing
Context parameter in the REG REQ. If the SGP determines that the
Routing Context applies to an existing Routing Key, the SG MAY adjust
the existing Routing Key to match the new information provided in the
Routing Key parameter. A Registration Response "Routing Key Change
Refused" is returned if the SGP does not accept the modification of
the Routing Key.
Upon successful registration of an ASP in an AS, the SGP can now send
related SS7 Signalling Network Management messaging, if this did not
previously start upon the ASP transitioning to state ASP-INACTIVE.
4.4.2. Deregistration
An ASP MAY dynamically deregister with an SGP as an ASP within an
Application Server using the DEREG REQ message. A Routing Context
parameter in the DEREG REQ message specifies which Routing Keys to
deregister. An ASP SHOULD move to the ASP-INACTIVE state for an
Application Server before attempting to deregister the Routing Key
(i.e., deregister after receiving an ASP Inactive Ack). Also, an ASP
SHOULD deregister from all Application Servers that it is a member
before attempting to move to the ASP-Down state.
The SGP examines the contents of the received Routing Context
parameter and validates that the ASP is currently registered in the
Application Server(s) related to the included Routing Context(s). If
validated, the ASP is deregistered as an ASP in the related
Application Server.
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The deregistration procedure does not necessarily imply the deletion
of Routing Key and Application Server configuration data at the SGP.
Other ASPs may continue to be associated with the Application Server,
in which case the Routing Key data SHOULD NOT be deleted. If a
Deregistration results in no more ASPs in an Application Server, an
SGP MAY delete the Routing Key data.
The SGP acknowledges the deregistration request by returning a DEREG
RSP message to the requesting ASP. The result of the deregistration
is found in the Deregistration Result parameter, indicating success
or failure with cause.
An ASP MAY deregister multiple Routing Contexts at once by including
a number of Routing Contexts in a single DEREG REQ message. The SGP
MAY respond to each deregistration request in a single DEREG RSP
message, indicating the success or failure result for each Routing
Context in a separate Deregistration Result parameter.
4.4.3. IPSP Considerations (REG/DEREG)
The Registration/Deregistration procedures work in the IPSP cases in
the same way as in AS-SG cases. An IPSP may register an RK in the
remote IPSP. An IPSP is responsible for deregistering the RKs that
it has registered.
4.5. Availability and/or Congestion Status of SS7 Destination Support
4.5.1. At an SGP
On receiving a N-STATE, N-PCSTATE and N-INFORM indication primitive
from the nodal interworking function at an SGP, the SGP SUA layer
will send a corresponding SS7 Signalling Network Management (SNM)
DUNA, DAVA, SCON, or DUPU message (see Section 3.4) to the SUA peers
at concerned ASPs. The SUA layer must fill in various fields of the
SNM messages consistently with the information received in the
primitives.
The SGP SUA layer determines the set of concerned ASPs to be informed
based on the specific SS7 network for which the primitive indication
is relevant. In this way, all ASPs configured to send/receive
traffic within a particular network appearance are informed. If the
SGP operates within a single SS7 network appearance, then all ASPs
are informed.
DUNA, DAVA, SCON, and DRST messages are sent sequentially and
processed at the receiver in the order sent. SCTP stream 0 SHOULD
NOT be used. The Unordered bit in the SCTP DATA chunk MAY be used
for the SCON message.
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Sequencing is not required for the DUPU or DAUD messages, which MAY
be sent unordered. SCTP stream 0 is used, with optional use of the
Unordered bit in the SCTP DATA chunk.
4.5.2. At an ASP
4.5.2.1. Single SG Configurations
At an ASP, upon receiving an SS7 Signalling Network Management (SSNM)
message from the remote SUA Peer, the SUA layer invokes the
appropriate primitive indications to the resident SUA-Users. Local
management is informed.
In the case where a local event has caused the unavailability or
congestion status of SS7 destinations, the SUA layer at the ASP
SHOULD pass up appropriate indications in the primitives to the SUA
User, as though equivalent SSNM messages were received. For example,
the loss of an SCTP association to an SGP may cause the
unavailability of a set of SS7 destinations. N-PCSTATE indication
primitives to the SUA User are appropriate.
Implementation Note: To accomplish this, the SUA layer at an ASP
maintains the status of routes via the SG.
4.5.2.2. Multiple SG Configurations
At an ASP, upon receiving a Signalling Network Management message
from the remote SUA Peer, the SUA layer updates the status of the
affected route(s) via the originating SG and determines, whether or
not the overall availability or congestion status of the effected
destination(s) has changed. If so, the SUA layer invokes the
appropriate primitive indications to the resident SUA-Users. Local
management is informed.
4.5.3. ASP Auditing
An ASP may optionally initiate an audit procedure to inquire of an
SGP the availability and, if the national congestion method with
multiple congestion levels and message priorities is used, congestion
status of an SS7 destination or set of destinations. A Destination
Audit (DAUD) message is sent from the ASP to the SGP requesting the
current availability and congestion status of one or more SS7
destinations or subsystems.
The DAUD message MAY be sent unordered. The ASP MAY send the DAUD in
the following cases:
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- Periodic. A Timer originally set upon reception of a DUNA, SCON or
DRST message has expired without a subsequent DAVA,
DUNA, SCON or DRST message updating the
availability/congestion status of the affected
Destination Point Code. The Timer is reset upon issuing
a DAUD. In this case the DAUD is sent to the SGP that
originally sent the SSNM message.
- Isolation. The ASP is newly ASP-ACTIVE or has been isolated from an
SGP for an extended period. The ASP MAY request the
availability/congestion status of one or more SS7
destinations to which it expects to communicate.
Implementation Note:
In the first of the cases above, the auditing procedure must not
be invoked for the case of a received SCON message containing a
congestion level value of "no congestion" or undefined" (i.e.,
congestion Level = "0"). This is because the value indicates
either congestion abatement or that the ITU MTP3 international
congestion method is being used. In the international congestion
method, the MTP3 layer at the SGP does not maintain the congestion
status of any destinations and therefore the SGP cannot provide
any congestion information in response to the DAUD. For the same
reason, in the second of the cases above a DAUD message cannot
reveal any congested destination(s).
The SGP SHOULD respond to a DAUD message with the availability and
congestion status of the subsystem. The status of each SS7
destination or subsystem requested is indicated in a DUNA message (if
unavailable), a DAVA message (if available), or a DRST (if restricted
and the SGP supports this feature). If the SS7 destination or
subsystem is available and congested, the SGP responds with an SCON
message in addition to the DAVA message. If the SS7 destination or
subsystem is restricted and congested, the SGP responds with an SCON
message in addition to the DRST. If the SGP has no information on
the availability / congestion status of the SS7 destination or
subsystem, the SGP responds with a DUNA message, as it has no routing
information to allow it to route traffic to this destination or
subsystem.
An SG MAY refuse to provide the availability or congestion status of
a destination or subsystem if, for example, the ASP is not authorized
to know the status of the destination or subsystem. The SG MAY
respond with an Error Message (Error Code = "Destination Status
Unknown") or Error Message (Error Code = "Subsystem Status Unknown").
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4.6. MTP3 Restart
In the case where the MTP3 in the SG undergoes an MTP restart, event
communication SHOULD be handled as follows:
When the SG discovers SS7 network isolation, the SGPs send an
indication to all concerned available ASPs (i.e., ASPs in the ASP-
ACTIVE state) using DUNA messages for the concerned destinations.
When the SG has completed the MTP Restart procedure, the SUA layer at
the SGPs inform all concerned ASPs in the ASP-ACTIVE state of any
available/restricted SS7 destinations using the DAVA/DRST message.
No message is necessary for those destinations still unavailable
after the restart procedure.
When the SUA layer at an ASP receives a DUNA message indicating SS7
destination unavailability at an SG, SCCP Users will receive an N-
PCSTATE indication and will stop any affected traffic to this
destination. When the SUA receives a DAVA/DRST message, SCCP Users
will receive an N-PCSTATE indication and can resume traffic to the
newly available SS7 destination via this SGP, provided the ASP is in
the ASP-ACTIVE state toward this SGP.
The ASP MAY choose to audit the availability of unavailable
destinations by sending DAUD messages. This would be for example the
case when an AS becomes active at an ASP and does not have current
destination statuses. If MTP restart is in progress at the SG, the
SGP returns a DUNA message for that destination, even if it received
an indication that the destination became available or restricted.
4.7. SCCP - SUA Interworking at the SG
4.7.1. Segmenting / Reassembly
When it is expected that signalling messages will not fit into a PDU
of the most restrictive transport technology used (e.g., 272-SIF of
MTP3), then segmenting/reassembly could be performed at the SG, ASP
or IPSP. If the SG, ASP or IPSP is incapable of performing a
necessary segmentation/reassembly, it can inform the peer of the
failure using the appropriate error in a CLDR or RESRE/COERR message.
4.7.2. Support for Loadsharing
Within an AS (identified by RK/RC parameters) several loadsharing
ASPs may be active.
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However, to assure the correct processing of TCAP transactions or
SCCP connections, the loadsharing scheme used at the SG must make
sure that messages continuing or ending the transactions/connections
arrive at the same ASP where the initial message (TC_Query, TC_Begin,
CR) was sent to/received from.
When the ASP can be identified uniquely based on RK parameters (e.g.,
unique DPC or GT), loadsharing is not required. When the ASPs in the
AS share state or use an internal distribution mechanism, the SG must
only take into account the in-sequence-delivery requirement. In case
of SCCP CO traffic, when the coupled approach is used, loadsharing of
messages other than CR is not required.
If these assumptions cannot be made, both SG and ASP should support
the following general procedure in a loadsharing environment.
4.7.2.1. Association Setup, ASP going active
After association setup and registration, an ASP normally goes active
for each AS it registered for. In the ASPAC message, the ASP
includes a TID and/or DRN Label Parameter, if applicable for the AS
in question. All the ASPs within the AS must specify a unique label
at a fixed position in the TID or DRN parameter. The same ASPAC
message is sent to each SG used for interworking with the SS7
network.
The SG builds, per RK, a list of ASPs that have registered for it.
The SG can now build up and update a distribution table for a certain
Routing Context, any time the association is (re-)established and the
ASP goes active. The SG has to perform some trivial plausibility
checks on the parameters:
- Start and End parameters values are between 0 and 31 for TID.
- Start and End parameters values are between 0 and 23 for DRN
- 0 < (Start - End + 1) <= 16 (label length maximum 16-bit)
- Start values are the same for each ASP within a RC
- End values are the same for each ASP within a RC
- TID and DRN Label values must be unique across the RC
If any of these checks fail, the SG refuses the ASPAC request, with
an error, "Invalid loadsharing label."
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4.7.3. Routing and message distribution at the SG
4.7.3.1. TCAP traffic
Messages not containing a destination (or "responding") TID, i.e.,
Query, Begin, Unidirectional, are loadshared among the available
ASPs. Any scheme permitting a fair load distribution among the ASPs
is allowed (e.g., round robin).
When a destination TID is present, the SG extracts the label and
selects the ASP that corresponds with it.
If an ASP is not available, the SG may generate (X)UDTS "routing
failure", if the return option is used.
4.7.3.2. SCCP Connection Oriented traffic
Messages not containing a destination reference number (DRN), i.e., a
Connection Request, MAY be loadshared among the available ASPs. The
load distribution mechanism is an implementation issue. When a DRN
is present, the SG extracts the label and selects the ASP that
corresponds with it. If an ASP is not available, the SG discards the
message.
4.7.4. Multiple SGs, SUA Relay Function
It is important that each ASP send its unique label (within the AS)
to each SGP. For a better robustness against association failures,
the SGs MAY cooperate to provide alternative routes toward an ASP.
Mechanisms for SG cooperation/coordination are outside of the scope
of this document.
5. Examples of SUA Procedures
The following sequence charts overview the procedures of SUA. These
are meant as examples, they do not, in and of themselves, impose
additional requirements upon an instance of SUA.
5.1. SG Architecture
The sequences below outline logical steps for a variety of scenarios
within a SG architecture. Please note that these scenarios cover a
Primary/Backup configuration. Where there is a load-sharing
configuration then the SGP can declare availability when 1 ASP issues
ASPAC but can only declare unavailability when all ASPs have issued
ASPIA.
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5.1.1. Establishment of SUA connectivity
The following is established before traffic can flow.
Each node is configured (via MIB, for example) with the connections
that need to be setup.
ASP-a1 ASP-a2 SG SEP
(Primary) (Backup)
|------Establish SCTP Association------|
|--Estab. SCTP Ass--|
|--Align SS7 link---|
+----------------ASP Up---------------->
<--------------ASP Up Ack--------------+
+------ASP Up------->
<---ASP Up Ack------+
+-------------ASP Active--------------->
<----------ASP Active Ack--------------+
<----------NTFY (ASP Active)-----------+
<-NTFY (ASP Active)-+
+--------SSA-------->
<--------SSA--------+
<-----------------DAVA-----------------+
+-----------------CLDT----------------->
+--------UDT-------->
5.1.2. Fail-over scenarios
The following sequences address fail-over of SEP and ASP.
5.1.2.1. SEP Fail-over
The SEP knows that the SGP is 'concerned' about its availability.
Similarly, the SGP knows that ASP-a1 is concerned about the SEPs
availability.
ASP-a1 ASP-a2 SG SEP
(Primary) (Backup)
<--------SSP--------+
<-----------------DUNA-----------------+
+-----------------DAUD----------------->
+--------SST-------->
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5.1.2.2. Successful ASP Fail-over scenario
The following is an example of a successful fail-over scenario, where
there is a fail-over from ASP-a1 to ASP-a2, i.e., Primary to Backup.
During the fail-over, the SGP buffers any incoming data messages from
the SEP, forwarding them when the Backup becomes available.
ASP-a1 ASP-a2 SG SEP
(Primary) (Backup)
+-------------ASP Inactive------------->
<-----------ASP Inactive ACK-----------+
<--------------------NTFY (AS Pending)-+
<-NTFY (AS Pending)-+
+----ASP Active----->
<--ASP Active Ack---+
<-NTFY (AS Active)--+
<----------NTFY (AS Active)------------+
5.1.2.3. Unsuccessful ASP Fail-over scenario
ASP-a1 ASP-a2 SG SEP
(Primary) (Backup)
+-------------ASP Inactive------------->
<-----------ASP Inactive ACK-----------+
<--------------------NTFY (AS Pending)-+
<--NTFY (AS Pending)-+
After some time elapses (i.e., timeout).
+--------SSP-------->
<--------SST--------+
<-------------------NTFY (AS Inactive)-+
<-NTFY (AS Inactive)-+
5.2. IPSP Examples
The sequences below outline logical steps for a variety of scenarios
within an IP-IP architecture. Please note that these scenarios cover
a Primary/Backup configuration. Where there is a load-sharing
configuration then the AS can declare availability when 1 ASP issues
ASPAC but can only declare unavailability when all ASPs have issued
ASPIA.
5.2.1. Establishment of SUA connectivity
The following shows an example establishment of SUA connectivity. In
this example, each IPSP consists of an Application Server and two
ASPs. The following is established before SUA traffic can flow. A
connectionless flow is shown for simplicity.
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Establish SCTP Connectivity - as per RFC 2960. Note that SCTP
connections are bidirectional. The endpoint that establishes SCTP
connectivity MUST also establish UA connectivity (see RFC 2960,
section 5.2.1 for handling collisions) [2960].
IP SEP A IP SEP B
AS A AS B
ASP-a1 ASP-a2 ASP-b2 ASP-b1
[All ASPs are in the ASP-DOWN state]
+-------------------------------ASP Up-------------------------->
<-----------------------------ASP Up Ack------------------------+
+--------------ASP Up--------------->
<------------ASP Up Ack-------------+
+---------------------------ACTIVE------------------------------->
<-------------------------ACTIVE Ack-----------------------------+
[Traffic can now flow directly between ASPs]
+-----------------------------CLDT------------------------------->
5.2.2. Fail-over scenarios
The following sequences address fail-over of ASP.
5.2.2.1. Successful ASP Fail-over scenario
The following is an example of a successful fail-over scenario, where
there is a fail-over from ASP-a1 to ASP-a2, i.e., Primary to Backup.
Since data transfer passes directly between peer ASPs, ASP-b1 is
notified of the fail-over of ASP-a1 and buffers outgoing data
messages until ASP-a2 becomes available.
IP SEP A IP SEP B
ASP-a1 ASP-a2 ASP-b2 ASP-b1
+-----------------------------ASP Inact------------------------>
<---------------------------ASP Inact Ack----------------------+
<---------------NTFY (ASP-a1 Inactive)--------------+
+---------------------ASP Act----------------------->
<-------------------ASP Act Ack---------------------+
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5.2.2.2. Unsuccessful ASP Fail-over scenario
The sequence is the same as 5.2.2.1 except that, since the backup
fails to come in then, the Notify messages declaring the availability
of the backup are not sent.
6. Security Considerations
The security considerations discussed for the 'Security
Considerations for SIGTRAN Protocols' [3788] document apply to this
document.
7. IANA Considerations
7.1. SCTP Payload Protocol ID
IANA has assigned a SUA value for the Payload Protocol Identifier in
the SCTP DATA chunk. The following SCTP Payload Protocol Identifier
is registered:
SUA "4"
The SCTP Payload Protocol Identifier value "4" SHOULD be included in
each SCTP DATA chunk, to indicate that the SCTP is carrying the SUA
protocol. The value "0" (unspecified) is also allowed but any other
values MUST not be used. This Payload Protocol Identifier is not
directly used by SCTP but MAY be used by certain network entities to
identify the type of information being carried in a DATA chunk.
The User Adaptation peer MAY use the Payload Protocol Identifier, as
a way of determining additional information about the data being
presented to it by SCTP.
7.2. Port Number
IANA has registered SCTP Port Number 14001 for SUA. It is
recommended that SGPs use this SCTP port number for listening for new
connections. SGPs MAY also use statically configured SCTP port
numbers instead.
7.3. Protocol Extensions
This protocol may also be extended through IANA in three ways:
- Through definition of additional message classes.
- Through definition of additional message types.
- Through definition of additional message parameters.
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The definition and use of new message classes, types and parameters
is an integral part of SIGTRAN adaptation layers. Thus, these
extensions are assigned by IANA through an IETF Consensus action as
defined in [2434].
The proposed extension MUST in no way adversely affect the general
working of the protocol.
A new registry has been created by IANA to allow the protocol to be
extended.
7.3.1. IETF Defined Message Classes
The documentation for a new message class MUST include the following
information:
(a) A long and short name for the message class;
(b) A detailed description of the purpose of the message class.
7.3.2. IETF Defined Message Types
Documentation of the message type MUST contain the following
information:
(a) A long and short name for the new message type;
(b) A detailed description of the structure of the message.
(c) A detailed definition and description of intended use of each
field within the message.
(d) A detailed procedural description of the use of the new message
type within the operation of the protocol.
(e) A detailed description of error conditions when receiving this
message type.
When an implementation receives a message type which it does not
support, it MUST respond with an Error (ERR) message, with an Error
Code = Unsupported Message Type.
7.3.4. IETF-defined TLV Parameter Extension
Documentation of the message parameter MUST contain the following
information:
(a) Name of the parameter type.
(b) Detailed description of the structure of the parameter field.
This structure MUST conform to the general type-length-value
format described earlier in the document.
(c) Detailed definition of each component of the parameter value.
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(d) Detailed description of the intended use of this parameter type,
and an indication of whether and under what circumstances
multiple instances of this parameter type may be found within the
same message type.
8. Timer Values
Ta 2 seconds
Tr 2 seconds
T(ack) 2 seconds
T(ias) Inactivity Send timer 7 minutes
T(iar) Inactivity Receive timer 15 minutes
T(beat) Heartbeat Timer 30 seconds
9. Acknowledgements
The authors would like to thank (in alphabetical order) Richard
Adams, Javier Pastor-Balbas, Andrew Booth, Martin Booyens, F.
Escobar, S. Furniss Klaus Gradischnig, Miguel A. Garcia, Marja-Liisa
Hamalainen, Sherry Karl, S. Lorusso, Markus Maanoja, Sandeep Mahajan,
Ken Morneault, Guy Mousseau, Chirayu Patel, Michael Purcell, W.
Sully, Michael Tuexen, Al Varney, Tim Vetter, Antonio Villena, Ben
Wilson, Michael Wright and James Yu for their insightful comments and
suggestions.
10. References
10.1. Normative References
[1123] Braden, R., Ed., "Requirements for Internet Hosts -
Application and Support", STD 3, RFC 1123, October
1989.
[2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[2960] Stewart, R., Xie, Q., Morneault, K., Sharp, C.,
Schwarzbauer, H., Taylor, T., Rytina, I., Kalla, M.,
Zhang, L., and V. Paxson, "Stream Control Transmission
Protocol", RFC 2960, October 2000.
[3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[3788] Loughney, J., Tuexen, M., Ed., and J. Pastor-Balbas,
"Security Considerations for Signaling Transport
(SIGTRAN) Protocols", RFC 3788, June 2004.
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RFC 3868 SUA October 2004
[ANSI SCCP] ANSI T1.112 "Signalling System Number 7 - Signalling
Connection Control Part".
[ITU SCCP] ITU-T Recommendations Q.711-714, "Signalling System
No. 7 (SS7) - Signalling Connection Control Part
(SCCP)." ITU-T Telecommunication Standardization
Sector of ITU, formerly CCITT, Geneva (July 1996).
10.2. Informative References
[2434] Narten, T. and H. Alvestrand, "Guidelines for Writing
an IANA Considerations Section in RFCs", BCP 26, RFC
2434, October 1998.
[2719] Ong, L., Rytina, I., Garcia, M., Schwarzbauer, H.,
Coene, L., Lin, H., Juhasz, I., Holdrege, M., and C.
Sharp, "Framework Architecture for Signalling
Transport", RFC 2719, October 1999.
[3761] Falstrom, P. and M. Mealling, "The E.164 to Uniform
Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)", RFC 3761,
April 2004.
[ANSI TCAP] ANSI T1.114 'Signalling System Number 7 - Transaction
Capabilities Application Part'
[ITU TCAP] ITU-T Recommendation Q.771-775 'Signalling System No.
7 SS7) - Transaction Capabilities (TCAP).'
[RANAP] 3G TS 25.413 V3.5.0 (2001-03) 'Technical Specification
3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; UTRAN Iu
Interface RANAP Signalling'
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Appendix A. Signalling Network Architecture
A.1. Generalized Peer-to-Peer Network Architecture
Figure 3 shows an example network architecture that can support
robust operation and fail-over. There needs to be some management
resources at the AS to manage traffic.
***********
* AS1 *
* +-----+ * SCTP Associations
* |ASP1 +-------------------+
* +-----+ * | ***********
* * | * AS3 *
* +-----+ * | * +-----+ *
* |ASP2 +-----------------------------------------+ASP1 | *
* +-----+ * | * +-----+ *
* * | * *
* +-----+ * | * +-----+ *
* |ASP3 | * +--------------------------+ASP2 | *
* +-----+ * | | * +-----+ *
*********** | | ***********
| |
*********** | | ***********
* AS2 * | | * AS4 *
* +-----+ * | | * +-----+ *
* |ASP1 +--------------+ +---------------------+ASP1 | *
* +-----+ * * +-----+ *
* * * *
* +-----+ * * +-----+ *
* |ASP2 +-----------------------------------------+ASP1 | *
* +-----+ * * +-----+ *
* * ***********
* +-----+ *
* |ASP3 | *
* +-----+ *
* *
***********
Figure 3: Generalized Architecture
In this example, the Application Servers are shown residing within
one logical box, with ASPs located inside. In fact, an AS could be
distributed among several hosts. In such a scenario, the host should
share state as protection in the case of a failure. This is out of
scope of this protocol. Additionally, in a distributed system, one
ASP could be registered to more than one AS. This document should
not restrict such systems - though such a case in not specified.
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A.2. Signalling Gateway Network Architecture
When interworking between SS7 and IP domains is needed, the SGP acts
as the gateway node between the SS7 network and the IP network. The
SGP will transport SCCP-user signalling traffic from the SS7 network
to the IP-based signalling nodes (for example IP-resident Databases).
The Signalling Gateway can be considered as a group of Application
Servers with additional functionality to interface toward an SS7
network.
The SUA protocol should be flexible enough to allow different
configurations and transport technology to allow the network
operators to meet their operation, management and performance
requirements.
An ASP may be connected to multiple SGPs (see figure 4). In such a
case, a particular SS7 destination may be reachable via more than SG,
therefore, more than one route. Given that proper SLS selection,
loadsharing, and SG selection based on point code availability is
performed at the ASP, it will be necessary for the ASP to maintain
the status of each distant SGPs to which it communicates on the basis
of the SG through which it may route.
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Signalling Gateway
SCTP Associations
+----------+ **************
| SG1 | * AS3 *
| ******** | * ******** *
| * SGP11+--------------------------------------------+ ASP1 * *
| ******** | / * ******** *
| ******** | | * ******** *
| * SGP12+--------------------------------------------+ ASP2 * *
| ******** | \ / | * ******** *
+----------+ \ | | * . *
\ | | * . *
+---------- \ | | * . *
| SG2 | \ | | * . *
| ******** | \ | | * ******** *
| * SGP21+---------------------------------+-+ * * ASPN * *
| ******** | \ * ******** *
| ******** | \ **************
| * SGP22+---+--+ \
| ******** | | | \ **************
+----------+ | | \ * AS4 *
| | \ * ******** *
| +-------------------------------------+ ASP1 * *
| * ******** *
| * . *
| * . *
| * *
| * ******** *
+----------------------------------------+ ASPn * *
* ******** *
**************
Figure 4: Signalling Gateway Architecture
The pair of SGs can either operate as replicated endpoints or as
replicated relay points from the SS7 network point of view.
Replicated endpoints: the coupling between the SGs and the ASPs when
the SGs act as replicated endpoints is an implementation issue.
Replicated relay points: in normal circumstances, the path from SEP
to ASP will always go via the same SGP when in-sequence-delivery is
requested. However, linkset failures may cause MTP to reroute to the
other SG.
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RFC 3868 SUA October 2004
A.3. Signalling Gateway Message Distribution Recommendations
A.3.1. Connectionless Transport
By means of configuration, the SG knows the local SCCP-user is
actually represented by an AS, and serviced by a set of ASPs working
in n+k redundancy mode. An ASP is selected and a CLDT message is
sent on the appropriate SCTP association/stream.
The selection criterion can be based on a round robin mechanism, or
any other method that guarantees a balanced loadsharing over the
active ASPs. However, when TCAP messages are transported, load
sharing is only possible for the first message in a TCAP dialogue
(TC_Begin, TC_Query, TC_Unidirectional). All other TCAP messages in
the same dialogue are sent to the same ASP that was selected for the
first message, unless the ASPs are able to share state and maintain
sequenced delivery. To this end, the SGP needs to know the TID
allocation policy of the ASPs in a single AS:
- State sharing
- Fixed range of TIDs per ASP in the AS
This information may be provisioned in the SG, or may be dynamically
exchanged via the ASP_Active message.
An example for an INAP/TCAP message exchange between SEP and ASP is
given below.
Address information in CLDT message (e.g., TC_Query) from SGP to ASP,
with association ID = SG-ASP, Stream ID based on sequence control and
possibly other parameters, e.g., OPC:
- Routing Context: based on SS7 Network ID and AS membership, so
that the message can be transported to the correct ASP.
- Source address: valid combination of SSN, PC and GT, as needed for
back routing to the SEP.
- Destination address: at least SSN, to select the SCCP/SUA-user at
the ASP.
Address information in CLDT message (e.g., TC_Response) from ASP to
SG, with association ID = ASP-SG, stream ID selected by
implementation dependent means with regards to in-sequence-delivery:
- Routing Context: as received in previous message.
- Source address: unique address provided so that when used as the
SCCP called party address in the SEP, it must yield the same AS,
the SSN might be sufficient.
Loughney, et al. Standards Track [Page 128]
RFC 3868 SUA October 2004
- Destination address: copied from source address in received CLDT
message.
Further messages from the SEP belonging to the same TCAP transaction
will now reach the same ASP.
A.3.2. Connection-Oriented Transport
Further messages for this connection are routed on DPC in the SS7
connection section (MTP routing label), and on IP address in the IP
connection section (SCTP header). No other routing information is
present in the SCCP or SUA messages themselves. Resources are kept
within the SG to forward messages from one section to another and to
populate the MTP routing label or SCTP header, based on the
destination local reference of these messages (Connect Confirm, Data
Transfer, etc.)
This means that in the SG, two local references are allocated, one
3-byte value used for the SS7 section and one 4-byte value for the IP
section. Also a resource containing the connection data for both
sections is allocated, and either of the two local references can be
used to retrieve this data e.g., for an incoming DT1 or CODT, for
example.
Authors' Addresses
John Loughney
Nokia Research Center
PO Box 407
FIN-00045 Nokia Group
Finland
EMail: john.Loughney@nokia.com
Greg Sidebottom
Signatus Technologies
Kanata, Ontario
Canada
EMail: greg@signatustechnologies.com
Loughney, et al. Standards Track [Page 129]
RFC 3868 SUA October 2004
Lode Coene
Siemens n.v.
Atealaan 34
B-2200 Herentals
Belgium
Phone: +32-14-252081
EMail: lode.coene@siemens.com
Gery Verwimp
Siemens n.v.
34 Atealaan
PO 2200
Herentals
Belgium
Phone: +32 14 25 3424
EMail: gery.verwimp@siemens.com
Joe Keller
Tekelec
5200 Paramount Parkway
Morrisville, NC 27560
USA
EMail: joe.keller@tekelec.com
Brian Bidulock
OpenSS7 Corporation
1469 Jeffreys Crescent
Edmonton, AB T6L 6T1
Canada
Phone: +1 780 490 1141
EMail: bidulock@openss7.org
Loughney, et al. Standards Track [Page 130]
RFC 3868 SUA October 2004
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Loughney, et al. Standards Track [Page 131]