Network Working Group
Request for Comments: 3868
Category: Standards Track
J. Loughney, Ed.
Nokia
G. Sidebottom
Signatus Technologies
L. Coene
G. Verwimp
Siemens n.v.
J. Keller
Tekelec
B. Bidulock
OpenSS7 Corporation
October 2004
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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 © 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
1.1. Scope
1.2. Abbreviations and Terminology
1.3. Signalling Transport Architecture
1.4. Services Provided by the SUA Layer
1.5. Internal Functions Provided in the SUA Layer
1.6. Definition of SUA Boundaries
2. Conventions
3. Protocol Elements
3.1. Common Message Header
3.2. SUA Connectionless Messages
3.3. Connection Oriented Messages
3.4. Signalling Network Management (SNM) Messages
3.5. Application Server Process State Maintenance Messages
3.6. ASP Traffic Maintenance Messages
3.7. SUA Management Messages
3.8. Routing Key Management (RKM) Messages
3.9. Common Parameters
3.10. SUA-Specific parameters
4. Procedures
4.1. Procedures to Support the SUA-User Layer
4.2. Receipt of Primitives from the Layer Management
4.3. AS and ASP State Maintenance
4.4. Routing Key Management Procedures
4.5. Availability and/or Congestion Status of SS7
Destination Support101
4.6. MTP3 Restart
4.7. SCCP - SUA Interworking at the SG
5. Examples of SUA Procedures
5.1. SG Architecture
5.2 IPSP Examples
6. Security Considerations
7. IANA Considerations
7.1. SCTP Payload Protocol ID
7.2. Port Number
7.3. Protocol Extensions
8. Timer Values
9. Acknowledgements
10. References
10.1. Normative References
10.2. Informative References


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Appendix A. Signalling Network Architecture
A.1. Generalized Peer-to-Peer Network Architecture
A.2. Signalling Gateway Network Architecture
A.3. Signalling Gateway Message Distribution
Recommendations
Authors' Addresses
Full Copyright Statement

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:


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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 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:

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.


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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.


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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.


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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.


Page 19

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.


Page 20

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


Page 21

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


Page 22

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.


Page 23

    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.


Page 24

   -  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                           |


Page 25

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         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.


Page 26

    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                              /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 27

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.


Page 28

    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).


Page 29

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)


Page 30

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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 31

   |                          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).


Page 32

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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 33

   /                     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).


Page 34

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                              /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 35

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).


Page 36

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).


Page 37

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).


Page 38

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).


Page 39

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).


Page 40

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).


Page 41

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.


Page 42

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                          /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 43

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.


Page 44

    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).


Page 45

    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.


Page 46

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


Page 47

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


Page 48

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


Page 49

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).


Page 50

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


Page 54

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                          /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 56

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                        /
   \                                                               \
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Page 57

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         |