INTERNET-DRAFT J. Loughney Internet Engineering Task Force Nokia G. Sidebottom, Guy Mousseau Issued: 24 November 2000 Nortel Networks Expires: 24 May 2001 S. Lorusso Unisphere Solutions L. Coede, G. Verwimp Siemens J. Keller Tekelec F. Escobar Ericsson W. Sully, S. Furniss Marconi SS7 SCCP-User Adaptation Layer (SUA) Status of This Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as 'work in progress.' The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html . This draft expires on 24 May 2001 Abstract This Internet Draft defines a protocol for the transport of any SS7 SCCP-User signaling (e.g., TCAP, RANAP, etc.) over IP using the Stream Control Transport Protocol. The protocol should be modular and symmetric, to allow it to work in diverse architectures, such as a Signaling Gateway to IP Signaling Endpoint architecture as well as a peer-to-peer IP Signaling Endpoint architecture. Protocol elements are added to allow seamless operation between peers in the SS7 and IP domains. Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Abstract..............................................................1 1. Introduction.......................................................3 1.1 Scope ...........................................................3 1.2 Terminology .....................................................3 1.3 Signaling Transport Architecture ................................5 1.4 Services Provided by the SUA Layer .............................10 1.5 Internal Functions Provided in the SUA Layer ...................11 1.6 Definition of SUA Boundaries ...................................12 2 Conventions........................................................13 3 Protocol Elements..................................................13 3.1 Common Message Header ..........................................14 3.2 SUA Connectionless Messages ....................................17 3.3 Connection Oriented Messages ...................................18 3.4 SS7 Signaling Network Management Messages ......................26 3.5 Application Server Process Maintenance Messages ................31 3.6 ASP Traffic Maintenance Messages ...............................34 3.7 Management Messages ............................................37 3.8 Common Parameters ..............................................38 3.9 SUA-Specific parameters ........................................46 4 Procedures.........................................................59 4.1 Peer Message Procedures ........................................59 4.2 Signaling Gateway Related Procedures ...........................60 4.3 Layer Management Procedures ....................................61 4.4 SCTP Management Procedures .....................................61 5 Examples of SUA Procedures.........................................68 5.1 SG Architecture ................................................68 5.2 IP-IP Architecture .............................................70 6 Message Routing Scenarios..........................................72 6.1 Basic case with single SG acting as end- or relay-point ........72 6.2 Replicated SG acting as end-point ..............................74 6.3 Replicated SG acting as relay-point ............................74 7 Security...........................................................75 7.1 Introduction ...................................................75 7.2 Threats ........................................................75 7.3 Protecting Confidentiality .....................................76 8 IANA Considerations................................................76 8.1 SCTP Payload Protocol ID .......................................76 8.2 Port Number ....................................................76 8.3 IETF Defined Message Classes ...................................77 9 Timer Values.......................................................78 10 Acknowledgements..................................................78 10 Authors' Addresses................................................78 11 References........................................................79 Appendix A: Message mapping between SCCP and SUA.....................80 Appendix B: Message Mapping Examples.................................82 1 SUA->SCCP ........................................................82 2 SCCP->SUA ........................................................82 Copyright Statement..................................................82 Loughney, et al. [Page 2] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 1. Introduction 1.1 Scope There is on-going integration of SCN networks and IP networks. Network service providers are designing all IP architectures which include support for SS7 and SS7-like signaling 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 may be some need for interworking between the SS7 and IP domains. This document details the delivery of SCCP-user messages (MAP & CAP over TCAP, RANAP, etc.) and new third generation network protocol messages over IP between two signaling endpoints. Consideration is given for the transport from an SS7 Signaling Gateway (SG) to an IP signaling node (such as an IP-resident Database) as described in the Framework Architecture for Signaling Transport [2719]. This protocol can also support transport of SCCP-user messages between two endpoints wholly contained within an IP network. The delivery mechanism SHOULD meet the following criteria: * Support for transfer of SS7 SCCP-User Part messages (e.g., TCAP, RANAP, etc.) * Support for SCCP connectionless service. * Support for SCCP connection oriented service. * Support for the seamless operation of SCCP-User protocol peers * Support for the management of SCTP transport associations between a SG and one or more IP-based signaling nodes). * Support for distributed IP-based signaling nodes. * Support for the asynchronous reporting of status changes to management The protocol is modular in design, allowing different implementations to be made, based upon the environment that needs to be supported. Depending upon the upper layer protocol supported, the SUA will need to support SCCP connectionless service, SCCP connect- orient service or both services. 1.2 Terminology Signaling Gateway (SG) - Network element that terminates SCN signaling and transports SCCP-User signaling over IP to an IP signaling endpoint. A Signaling Gateway could be modeled as one or more Application Servers, which is located at the border of the SS7 and IP networks. Application Server (AS) - A logical entity serving a specific Routing Key. An example of an Application Server is an IP database handling all request for a unique set of SCCP-users. The AS Loughney, et al. [Page 3] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 standby process of an Application Server (e.g., part of a distributed signaling node or database element). Examples of ASPs are MGCs, IP SCPs, or IP-based HLRs. An ASP contains an SCTP end-point and may be configured to process traffic within more than one Application Server. Association - An association refers to an SCTP association. The association provides the transport for the delivery of SCCP-User protocol data units and SUA adaptation layer peer messages. Routing Key - The Routing Key describes a set of SS7 parameter and /or parameter-ranges that uniquely defines the range of signaling traffic configured to be handled by a particular Application Server. An example would be where a Routing Key consists of a particular PC and SSN to which all traffic would be directed to a particular Application Server. Routing Keys are mutually exclusive in the sense that a received SS7 signaling message cannot be directed to more than one Routing Key. A Routing Key cannot extend across more than a single SS7 PC, in order to more easily support SS7 Management procedures. It is not necessary for the parameter ranges within a particular Routing Key to be contiguous. 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 two ASPs, identifying the relevant Application Server. From the perspective of an 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. Fail-over - The capability to re-route signaling 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-back may apply upon the return to service of a previously unavailable Application Server Process. Signaling Point Management Cluster (SPMC) - A complete set of Application Servers represented to the SS7 network under the same SS7 Point Code. SPMCs are used to sum the availability / congestion / User_Part status of an SS7 destination point code that is distributed in the IP domain, for the purpose of supporting management procedures at an SG. Loughney, et al. [Page 4] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Network Appearance - The Network Appearance identifies an SS7 network context for the purposes of logically separating the signaling traffic between the SG and the Application Server Processes over a common SCTP Association. An example is where an SG is logically partitioned to appear as an element in four separate national SS7 networks. A Network Appearance implicitly defines the SS7 Point Code(s), Network Indicator and SCCP protocol type/variant/version used within a specific SS7 network partition. An physical SS7 route-set or link-set at an SG can appear in only one network appearance. The Network Appearance is not globally significant and requires coordination only between the SG and the ASP. Network Byte Order - Most significant byte first, a.k.a. Big Endian. Layer Management - Layer Management is a nodal function in an SG or ASP that handles the inputs and outputs between the SUA layer and a local management entity. Host - The computing platform that the ASP process is running on. Stream - A stream refers to an SCTP stream; a uni-directional logical channel established from one SCTP endpoint to another associated SCTP endpoint, within which all user messages are delivered in-sequence except for those submitted to the un-ordered delivery service. Transport address - an address which 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 Signaling Transport Architecture The framework architecture that has been defined for SCN signaling transport over IP [2719] uses multiple components, including an IP transport protocol, a signaling common transport protocol and an adaptation module to support the services expected by a particular SCN signaling protocol from its underlying protocol layer. In general terms, the SUA architecture can be modeled as a peer-to- peer architecture. 1.3.1 Protocol Architecture for TCAP Transport In this architecture, the SCCP and SUA layers interface in the SG. There needs to be interworking between the SCCP and SUA layers to provide for the seamless transfer of the user messages as well as Loughney, et al. [Page 5] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 the management messages. The SUA handles the SS7 address to IP address mapping. ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * * STP * * * * * ******** *************** ******** +------+ +------+ | TCAP | | TCAP | +------+ +------+------+ +------+ | SCCP | | SCCP | SUA | | SUA | +------+ +------+------+ +------+ | MTP3 | | MTP3 | | | | +------| +------+ SCTP | | SCTP | | MTP2 | | MTP2 | | | | +------+ +------+------+ +------+ | L1 | | L1 | IP | | IP | +------+ +------+------+ +------+ | | | | +---------------+ +------------+ TCAP - Transaction Capability Application Protocol STP - SS7 Signaling Transfer Point 1.3.2 Protocol Architecture for RANAP Transport In this architecture, the SS7 application protocol is invoked at the SG. For messages destined for an ASP, the SUA handles address translation, for example by way of Global Title Translation or via mapping table, resolving the destination specified by SS7 Application to a SCTP association / IP address. ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * * STP * * * * * ******** *************** ******** +------+ +-------------+ +------+ | S7AP | | S7AP | | S7AP | +------+ +------+------+ +------+ | SCCP | | SCCP | SUA | | SUA | +------+ +------+------+ +------+ | MTP3 | | MTP3 | | | | +------| +------+ SCTP | | SCTP | | MTP2 | | MTP2 | | | | +------+ +------+------+ +------+ | L1 | | L1 | IP | | IP | +------+ +------+------+ +------+ Loughney, et al. [Page 6] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 | | | | +---------------+ +------------+ S7AP - SS7 Application Protocol (e.g. - RANAP/RNSAP) STP - SS7 Signaling Transfer Point This architecture may simplify, in some cases, to carrying an SS7 application protocol between two IP based endpoints. In this scenario, full SG functionality may not be needed. This architecture is considered in the next section. 1.3.3 All IP Architecture This architecture can be used to carry a protocol which uses the transport services of SCCP, but is contained with an IP network. This allows extra flexibility in developing networks, especially when interaction between legacy signaling is not needed. The architecture removes the need for signaling gateway functionality. ******** IP ******** * *--------* * * AS * * AS * * * * * ******** ******** +------+ +------+ | AP | | AP | +------+ +------+ | SUA | | SUA | +------+ +------+ | SCTP | | SCTP | +------+ +------+ | IP | | IP | +------+ +------+ | | +----------------+ AP - Application Protocol (e.g. - RANAP/RNSAP) In the case where a collision occurs during initiation, there exist two possible solutions: 1) if there are sufficient resources, both initiations could be accepted; 2) both ASPs should back-off and after some amount of time, later re-establish an initiation. 1.3.4 Generalized Point-to-Point Network Architecture Figure 1 shows an example network architecture which can support robust operation and failover support. There needs to be some management resources at the AS to manage traffic. Loughney, et al. [Page 7] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 *********** * AS1 * * +-----+ * SCTP Associations * |ASP1 +-------------------+ * +-----+ * | *********** * * | * AS3 * * +-----+ * | * +-----+ * * |ASP2 +-----------------------------------------+ASP1 | * * +-----+ * | * +-----+ * * * | * * * +-----+ * | * +-----+ * * |ASP3 | * +--------------------------+ASP2 | * * +-----+ * | | * +-----+ * *********** | | *********** | | *********** | | *********** * AS2 * | | * AS4 * * +-----+ * | | * +-----+ * * |ASP1 +--------------+ +---------------------+ASP1 | * * +-----+ * * +-----+ * * * * * * +-----+ * * +-----+ * * |ASP2 +-----------------------------------------+ASP1 | * * +-----+ * * +-----+ * * * *********** * +-----+ * * |ASP3 | * * +-----+ * * * *********** Figure 1: Generalized Architecture In this example, the Application Servers are shown residing within one logical box, with ASPs located inside. In fact, an AS could be distributed among several hosts. In such a scenario, the host should share state as protection in the case of a failure. Additionally, in a distributed system, one ASP could be registered to more than one AS. This draft should not restrict such systems - though such a case in not specified. 1.3.5 Generalized Signaling Gateway Network Architecture When interworking between SS7 and IP domains is needed, the SG acts as the gateway node between the SS7 network and the IP network. The SG will transport SCCP-user signaling traffic from the SS7 network to the IP-based signaling nodes (for example IP-resident Databases). The Signaling Gateway can be considered as a group of Application Servers with additional functionality to interface towards an SS7 network. Loughney, et al. [Page 8] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The SUA protocol should be flexible enough to allow different configurations and transport technology to allow the network operators to meet their operation, management and performance requirements. Figure 2 shows a possible realization of this architecture, with Signaling Gateway functionality. Signaling Gateway **************** * +----------+ * ************** * | AS1 | * * AS3 * * | ******** | * * ******** * * | * ASP1 +---------------------------------------------+ ASP1 * * * | ******** | * * ******** * * | ******** | * * ******** * * | * ASP2 +--------------------------+ +----------+ ASP2 * * * | ******** | * | | * ******** * * +----------+ * | | * . * * +----------+ * | | * . * * | AS2 | * | | * . * * | ******** | * | | * ******** * * | * ASP1 +----------------------------------+ * * ASPN * * * | ******** | * SCTP Associations | * ******** * * | ******** | * | ************** * | * ASP2 +---------------- | * | ******** | * | | ************** * +----------+ * | | * AS4 * **************** | | * ******** * | +------------------+ ASP1 * * | * ******** * | * . * | * . * | * * | * ******** * +-----------------------------+ ASPn * * * ******** * ************** Figure 2: Signaling Gateway Architecture 1.3.6 ASP Fail-over Model and Terminology The SUA protocol supports ASP fail-over functions in order 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 Loughney, et al. [Page 9] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 others may while any others are inactive but available in the event of failure or unavailability of the active ASP(s). The fail-over model supports an "n+k" redundancy model, where "n" ASPs is the minimum number of redundant ASPs required to handle traffic and "k" ASPs are available to take over for a failed or unavailable ASP. Note that "1+1" active/standby redundancy is a subset of this model. A simplex "1+0" model is also supported as a subset, with no ASP redundancy. To avoid a single point of failure, it is recommended that a minimum of two ASPs be resident in the list, resident in separate physical hosts and therefore available over different SCTP Associations. 1.4 Services Provided by the SUA Layer 1.4.1 Support for the transport of SCCP-User Messages The SUA needs to support the transfer of SCCP-user messages. The SUA layer at the SG needs to seamlessly transport the user messages. 1.4.2 SCCP Protocol Class Support Depending upon the SCCP-users supported, the SUA shall support the 4 possible SCCP protocol classes transparently. The SCCP protocol classes are defined as follows: * Protocol class 0 provides unordered transfer of SCCP-user messages in a connectionless manner. * Protocol class 1 allows the SCCP-user to select the in-sequence delivery of SCCP-user messages in a connectionless manner. * Protocol class 2 allows the bi-directional transfer of SCCP-user messages by setting up a temporary or permanent signaling connection. * Protocol class 3 allows the features of protocol class 2 with the inclusion of flow control. Detection of message loss or mis-sequencing is included. Protocol classes 0 and 1 make up the SCCP connectionless service. Protocol classes 2 and 3 make up the SCCP connection-oriented service. 1.4.3 Native Management Functions The SUA layer may provide management of the underlying SCTP layer to ensure that transport is available according to the degree specified by the SCCP-user application. Loughney, et al. [Page 10] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 The SUA layer needs to support the following SCCP network management primitives (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-Coord |Request |ITU-Q.711 Chap 6.3.2.3.1 (Tab 13/Q.711) |Indication |ANSI-T1.112 Chap 2.3.2.3.1 (Tab 8D/T1.112.1) |Response | |Confirm | ----------+-----------+--------------------------------------------- N-State |Request |ITU-Q.711 Chap 6.3.2.3.2 (Tab 14/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 15/Q.711) | |ANSI-T1.112 Chap 2.3.2.3.4 (Tab 8G/T1.112.1) 1.4.5 Support for the management between the SG and ASP. The SUA layer should provide interworking with SCCP management functions at the SG for seamless inter-operation between the SCN network and the IP network. It should: * Provide an indication to the SCCP-user at an ASP that a remote SS7 endpoint/peer is unreachable. * Provide an indication to the SCCP-user at an ASP that a remote SS7 endpoint/peer is reachable. * Provide congestion indication to SCCP-user at an ASP. * Provide the initiation of an audit of remote SS7 endpoints at the SG. 1.5 Internal Functions Provided in the SUA Layer 1.5.1 Address Translation and Mapping at the SG SCCP users may present the following options to address their peer endpoints: Global Title PC + SSN Host Name IP Address(es) Loughney, et al. [Page 11] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The SG MUST translate the SS7 address presented at the SG (PC + SSN or GT) to an SCTP-based ASP final destination, and not to another SS7 MTP destination. Global Titles are an interesting option for addressing. Currently, the ITU does not support translation of Global Titles to IP addresses. However, IP addresses are global in scope. There exist many proprietary schemes for managing SS7 Address Translation to IP addresses, and is considered outside of the scope of this document to specify how this is done. Some discussion of address translation should be made to insure interoperability between implementations of the SUA. For further instruction in the use of Global Titles the rules detailed in Annex B of ITU Q.713 [ITU SCCP] or [ANSI SCCP] should be consulted. That being said, currently, there is some work within the IETF studying translation of E.164 numbers to Host Names [ENUMS], [E.164- DNS]. In many cases, the network operator may have some control over the SCCP-user protocols being transported by SUA. If possible, the Upper Layer can present a Host Name or IP Address, which then can be directly passed to SCTP. An example of address translation at the SG would be that the CDPA is extracted from the SCCP Header, processed by the SUA routing function which yields a SA. The SA is fed back into extended SUA routing analysis which yields the ASP to route the message to. This is why the Source Address and Destination address-routing should be performed based on the CDPA. 1.5.2 SCTP Stream Mapping The SUA supports SCTP streams. The SG/AS needs 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 supporting sequenced delivery. SUA MUST use stream 0 for SUA management messages. It is recommended that sequenced delivery be in order to preserve the order of management message delivery. 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): Loughney, et al. [Page 12] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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) ------------+----------+------------------------------------------- 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 6.1.1.3.1 (Tab 7/Q.711) |Indication|ANSI-T1.112 Chap 2.1.1.2.5 (Tab 6A/T1.112.1) ------------+----------+------------------------------------------- N-Unit Data |Request |ITU-Q.711 Chap 6.2.2.3.1 (Tab 10/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 11/Q.711) | |ANSI-T1.112 Chap 2.2.2.3.2 (Tab 8B/T1.112.1) 1.6.2 Definition of the lower boundary The upper layer primitives provided by the SCTP are provided in [SCTP]. 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 [RFC2119]. 3 Protocol Elements The general message format includes a Common Message Header together with a list of zero or more parameters as defined by the Message Type. For forward compatibility, all Message Types may have attached parameters even if none are specified in this version. Loughney, et al. [Page 13] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 3.1 Common Message Header The protocol messages for the SCCP-User Adaptation Protocol requires a message structure which contains a version, message type, message length and message contents. This message header is common among all signaling 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | msg 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: 01 SUA version 1.0 3.1.2 Message Classes Message Classes 0 Management (MGMT) Message 1 Reserved 2 SS7 Signaling Network Management (SSNM) 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 - 127 Reserved by the IETF 128 - 255 Reserved for IETF-Defined Message Class Extensions 3.1.3 Message Types SUA Management Messages 0 Error (ERR) Loughney, et al. [Page 14] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 1 Notify (NTFY) 2 - 127 Reserved by the IETF 128- 255 Reserved for IETF-Defined Message Class Extensions SS7 Signaling Network Management (SSNM) Messages 0 Reserved 1 Destination Unavailable (DUNA) 2 Destination Available (DAVA) 3 Destination State Audit (DAUD) 4 SS7 Network Congestion (SCON) 5 Destination User Part Unavailable (DUPU) 6 SCCP Management (SCMG) 7 - 127 Reserved by the IETF 128 - 255 Reserved for IETF-Defined Message Class Extensions Application Server Process Maintenance (ASPM) 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 Connectionless 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 Messages 0 Reserved 1 Connection Request (CORE) 2 Connection Acknowledge (COAK) Loughney, et al. [Page 15] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 - 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. 3.1.4 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. 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 65534. 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. Parameter Value: variable-length. The Parameter Value field contains the actual information to be transferred in the parameter. The total length of a parameter (including Tag, Parameter Length Loughney, et al. [Page 16] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 NEVER pad with more than 3 bytes. The receiver MUST ignore the padding bytes. 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 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 = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Flags Mandatory Source Address Mandatory Destination Address Mandatory Data Mandatory Implementation note: Loughney, et al. [Page 17] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 This message covers the following SCCP messages: unitdata (UDT), extended unitdata (XUDT), long unitdata (LUDT). 3.2.2 Connectionless Data Response This message is used as a response message by the peer and/or report errors. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Error Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Flags Mandatory SCCP Error Cause Mandatory Source Address Mandatory Destination Address Mandatory Data Optional Implementation note: This message covers the following SCCP messages: long unitdata service (LUDTS), unitdata service (UDTS), extended unitdata service (XUDTS). 3.3 Connection Oriented Messages Loughney, et al. [Page 18] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 3.3.1 Connection Oriented Data Transfer This message transfers data between one SUA to another for connection oriented service. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Data Mandatory Flags Mandatory *1 Sequence number Mandatory *2 NOTE *1: Mandatory for representing DT1 message. NOTE *2: Mandatory when CODT message maps a DT2 message. Otherwise, the parameter is not be present. Implementation note: This message covers the following SCCP messages: data form 1 (DT1), data form 2 (DT2), expedited data (ED). 3.3.2 Connection Oriented Data Acknowledge This message is used to acknowledge receipt of data by the peer. This message is used only with protocol class 3. Loughney, et al. [Page 19] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010F | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Receive Sequence number Mandatory *1 Credit Mandatory *1 NOTE *1: Mandatory when representing Data Acknowledgement (AK). Implementation note: This message covers the following SCCP messages: data acknowledgement (AK), expedited data acknowledgement (EA). 3.3.3 Connect Request This message is used for establishing a signaling connection between two peer endpoints. This is used for connection oriented service. Loughney, et al. [Page 20] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Flags Mandatory Source Reference Number Mandatory Destination Address Mandatory Source Address Optional Credit Optional Data Optional 3.3.4 Connection Acknowledge This message is used to acknowledge a connection request between two peer endpoints. Loughney, et al. [Page 21] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Flags Mandatory Credit 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. Implementation note: This message covers the following SCCP message: connection confirm (CC). 3.3.5 Connection Refused (COREF) This message is used to refuse a connection request between two peer endpoints. Loughney, et al. [Page 22] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Error Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory SCCP Error Cause Mandatory 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. 3.3.6 Release Request This message is used to request a signaling connection between two peer endpoints be released. All associated resources can then be released. Loughney, et al. [Page 23] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Return Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Return Cause Mandatory Flags Optional Data Optional Implementation Note: This message covers the following SCCP message: connection refused (CREF). 3.3.7 Release Complete This message is used to acknowledge the release of a signaling connection between two peer endpoints. All associated resources should be released. Loughney, et al. [Page 24] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory 3.3.8 Reset Request This message is used to indicate that the sending SCCP/SUA wants to initiate a reset procedure (re-initialization of sequence numbers) 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 = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Error Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory SCCP Error Cause Mandatory 3.3.9 Reset Confirm This message is used to confirm the Reset Request. Loughney, et al. [Page 25] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory 3.3.10 Connection Oriented Error (COERR) The COERR message is sent when an invalid value is found in an incoming 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 = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Error Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory SCCP Error Cause Mandatory Implementation Note: This message covers the following SCCP message: Protocol data unit error (ERR) 3.4 SS7 Signaling Network Management Messages 3.4.1 Destination Unavailable The DUNA message is sent from the SG to all concerned ASPs to indicate that the SG has determined that an SS7 destination is unreachable. The SUA-User at the ASP is expected to stop traffic to the affected destination through the SG initiating the DUNA. Loughney, et al. [Page 26] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Affected Point Code Mandatory Network Appearance Optional Info String Optional 3.4.2 Destination Available The DAVA message is sent from the SG to all concerned ASPs to indicate that the SG has determined that an SS7 destination is now reachable. The ASP SUA-User protocol is expected to resume traffic to the affected destination through the SG initiating the DAVA. 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Loughney, et al. [Page 27] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Affected Point Code Mandatory Network Appearance Optional Info String Optional 3.4.3 Destination State Audit The DAUD message can be sent from the ASP to the SG to query the availability state of the SS7 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. 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Affected Point Code Mandatory Network Appearance Optional Info String Optional 3.4.4 SS7 Network Congestion The SCON message can be sent from the SG to all concerned ASPs to indicate that the congestion level in the SS7 network to a specified destination has changed. Loughney, et al. [Page 28] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0010 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Congestion Level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ \ Affected PC(s) \ / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Congestion Level Mandatory Affected PCs Mandatory Info String Optional 3.4.5 Destination User Part Unavailable The DUPU message is used by an SG to inform an ASP that a remote peer SUA-User User Part at an SS7 node is unavailable. The format for DUPU Message parameters is as follows: Loughney, et al. [Page 29] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0009 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause/User | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Affected Point Code Mandatory Note *1 Cause/User Mandatory Info String Optional 3.4.6 SCCP Management Message The SCMG message is sent between SUA Peers to indicate status of subsystems. Only one SCMG message type can be sent per message. Loughney, et al. [Page 30] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010D | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCMG Message Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010E | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMI | Subsystem | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected PC / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0108 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | congestion level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String \ \ / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters SCMG Message Type Mandatory Subsystem/SMI Mandatory Affected Point Code Mandatory *1 Congestion Level Mandatory *2 Info String Optional Note *1: In the SCMG message, the Affected Point Code Parameter MUST contain, at most, a single Affected Point Code. Note *2: When the SCMG Message Type is SSC, then the Congestion Level parameter is Mandatory, otherwise it is optional. 3.5 Application Server Process Maintenance Messages 3.5.1 ASP Up (ASPUP) The ASP UP (ASPUP) message is used to indicate to a remote SUA peer that the Adaptation layer is up and running. Loughney, et al. [Page 31] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ASP Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters ASP Capabilities Optional Info String Optional 3.5.2 ASP Up Ack (UPACK) 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 = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ASP Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters ASP Capabilities Optional Info String Optional 3.5.3 ASP Down (ASPDN) The ASP Down (ASPDN) message is used to indicate to a remote SUA peer that the adaptation layer is not running. Loughney, et al. [Page 32] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 = 0x0002 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Cause Code Mandatory Info String Optional 3.5.4 ASP Down Ack (DNACK) 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 = 0x0002 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Reason Mandatory Info String Optional 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: Loughney, et al. [Page 33] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 = 8 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Heartbeat Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Heartbeat Data Optional 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 = 8 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Heartbeat Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Heartbeat Data Optional 3.6 ASP Traffic Maintenance Messages 3.6.1 ASP Active (ASPAC) The ASPAC message is sent by an ASP to indicate to a remote SUA peer that it is Active and ready to process signaling traffic for a particular Application Server The format for the ASPAC message is as follows: Loughney, et al. [Page 34] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Status Type Mandatory Routing Context Optional INFO String Optional 3.6.2 ASP Active Ack The ASPAC Ack message is used to acknowledge an ASP-Active message received from a remote SUA peer. The format for the ASPAC 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 = 0x000D | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Status Type Mandatory Loughney, et al. [Page 35] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Routing Context Optional INFO String Optional The Status Type field in the ASPAC Ack message should contain the type as the ASPAC message to which the message is acknowledging. 3.6.3 ASP Inactive (ASPIA) The ASPIA message is sent by an ASP to indicate to a remote SUA peer that it is no longer processing signaling 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 = 0x000D | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Status Type Mandatory Routing Context Optional INFO String Optional A node that receives an ASPIA with an incorrect Type for a particular Routing Context will respond with an Error Message (Cause: Invalid Traffic Handling Mode). 3.6.4 ASP Inactive Ack The ASPIA Ack message is used to acknowledge an ASP-Inactive message received from a remote SUA peer. The format for the ASPIA Ack message is as follows: Loughney, et al. [Page 36] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Status Type Mandatory Routing Context Optional INFO String Optional The Status Type field in the Ack message should contain the type as the ASPIA message to which the message is acknowledging. 3.7 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 Data 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 = 0x0007 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Diagnostic Info / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Loughney, et al. [Page 37] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Error Code Mandatory Diagnostic Info Optional 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 Type / Status ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The NTFY message contains the following parameters: Parameters Status Type Mandatory Routing Context Optional Info String Optional 3.8 Common Parameters These TLV parameters are common across the different adaptation layers. Parameter Name Parameter ID ============== ============ Network Appearance 0x0001 Cause Code 0x0002 Data 0x0003 Info String 0x0004 Affected Point Code 0x0005 Routing Context 0x0006 Diagnostic Info 0x0007 Heartbeat Data 0x0008 Cause/User 0x0009 Congestion 0x000A Not used 0x000B Loughney, et al. [Page 38] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Not used 0x000C Status Type / Status ID 0x000D 3.8.1 Network Appearance The Network Appearance parameter identifies the SS7 network context for the message, for the purposes of logically separating the signaling traffic between the SG and the Application Server Processes over common SCTP Associations. An example is where an SG is logically partitioned to appear as an element in four different national SS7 networks. A Network Appearance implicitly defines the SS7 Destination Point Code used, the SS7 Network Indicator value and SCCP/SCCP-User protocol type/variant/version used within the SS7 network partition. Where an SG operates in the context of a single SS7 network, or individual SCTP associations are dedicated to each SS7 network appearance, the Network Appearance parameter is not required. 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ In an SSNM message, the Network Appearance parameter defines the format of the Affected PC(s) in the Affected Destination parameter. The PC point code length (e.g., 14-, 16-, or 24-bit) and sub-field definitions (e.g., ANSI 24-bit network/cluster/member, ITU- international 14-bit zone/region/signal_point, many national field variants, ...) are fixed within a particular Network Appearance. Where an SG operates in the context of a single SS7 network, or individual SCTP associations are dedicated to each SS7 network context, the Network Appearance parameter is not required and the format of the Affected PC(s) is understood implicitly. The format of the Network Appearance parameter is an integer, the values of which are assigned according to network operator policy. The values used are of local significance only, coordinated between the SG and ASP. Where the optional Network Appearance parameter is present, it must be the first parameter in the message as it defines the format of the Affected PCs in the Affected Destination parameter. 3.8.2 Cause Code The Cause Code parameter indicates the reason that the remote SUA adaptation layer is unavailable. The valid values for Reason are shown in the following table. Loughney, et al. [Page 39] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Value Description 0x1 Processor Outage 0x2 Management Inhibit 3.8.3 Data 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.8.4 Info String The INFO String parameter can carry any meaningful 8-BIT ASCII character string along with the message. Length of the INFO String parameter is from 0 to 255 characters. No procedures are presently identified for its use but the INFO String may be used by Operators for debugging purposes. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.8.5 Affected Point Code The Affected Point Code parameter contains one or more Affected Destination Point Codes, each a three-octet parameter to allow for 4-, 16- and 24-bit binary formatted SS7 Point Codes. Affected Point codes that are less than 24-bits, are padded on the left to the 24- bit boundary. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mask | Affected PC 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / . . . / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 40] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The encoding is shown below for ANSI and ITU Point Code examples. ANSI 24-bit Point Code: 0 1 2 3--> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mask | Network | Cluster | Member | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |MSB-----------------------------------------LSB| ITU 14-bit Point Code: 0 1 2 3--> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mask |0 0 0 0 0 0 0 0 0 0|Zone | Region | SP | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |MSB--------------------LSB| It is optional to send an Affected Pointe Code parameter with more than one Affected PC but it is mandatory to receive it. All the Affected PCs included must be within the same Network Appearance. Including multiple Affected PCs may be useful when reception of an management message or a linkset event simultaneously affects the availability status of a list of destinations at an SG. Mask: 8-bits The Mask parameter is used to identify a contiguous range of Affected Destination Point Codes, independent of the point code format. Identifying a contiguous range of Affected PCs may be useful when reception of an MTP3 management message or a linkset event simultaneously affects the availability status of a series of destinations at an SG. The Mask parameter is an integer representing a bit mask that can be applied to the related Affected PC field. The bit mask identifies how many bits of the Affected PC field is significant and which are effectively "wildcarded". For example, a mask of "8" indicates that the last eight bits of the PC is "wildcarded". For an ANSI 24-bit Affected PC, this is equivalent to signaling that all PCs in an ANSI Cluster are unavailable. A mask of "3" indicates that the last three bits of the PC is "wildcarded". For a 14-bit ITU Affected PC, this is equivalent to signaling that an ITU Region is unavailable. 3.8.6 Routing Context Loughney, et al. [Page 41] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Routing Context parameter contains (a list of) integers indexing the Application Server traffic that the sending ASP is configured to receive. There is one-to-one relationship between an index entry and an AS Name. Because an AS can only appear in one Network Appearance, the Network Appearance parameter is not required in the ASPAC message An Application Server Process may be configured to process traffic for more than one logical Application Server. From the perspective of an ASP, a Routing Context defines a range of signaling traffic that the ASP is currently configured to receive from the SG. 3.8.7 Diagnostic Information The Diagnostic Information can be used to convey any information relevant to an error condition, to assist in the identification of the error condition. In the case of an Invalid Network Appearance, Adaptation Layer Identifier or Traffic Handling Mode, the Diagnostic information includes the received parameter. In the other cases, the Diagnostic information may be the first 40 bytes of the offending message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0007 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Diagnostic Information* / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.8.8 Heartbeat Data 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 8 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Heartbeat Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 42] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The data field can be used to store information in the heartbeat message useful to the sending node (e.g. the data field can contain a time stamp, a sequence number, etc.). 3.8.9 Cause/User 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 = 9 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | User | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Unavailability Cause field: 16-bits (unsigned integer) The Unavailability Cause parameter provides the reason for the unavailability of the SUA-User. The valid values for the Unavailability Cause parameter are shown in the following table. 0 Unknown 1 Unequipped Remote User 2 Inaccessible Remote User User Identity field: 16-bits (unsigned integer) The User Identity describes the specific SUA-User that is unavailable. Some of the valid values for the User Identity are shown below. 0 - 2 Reserved by M3UA 3 SCCP/SUA 4 - 10 Reserved by M3UA 3.8.10 Congestion Level 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0010 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Congestion Level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Congestion Level field: 8-bits (unsigned integer) The Congestion Level will have two different meanings, depending upon the message it is received with. Loughney, et al. [Page 43] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 For the SCON message, the Congestion Level field, contains one of the following values, which are associated with a destination point code: 0 No Congestion or Undefined 1 Congestion Level 1 2 Congestion Level 2 3 Congestion Level 3 The congestion levels are as defined in the national congestion method in the appropriate MTP recommendation [ITU-MTP], [ANSI-MTP]. For MTP congestion methods that do not employ congestion levels (e.g., the ITU international method, the parameter is always "Undefined"). When an SCON is received at the SG, a TFC message is generated into the SS7 network. For the SCMG message, the valid values for the Congestion Level parameter range from 0 to 7, where 0 indicates least congested and 7 indicates most congested. 4.8.11 Error Code 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag =0x000C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Error Code parameter indicates the reason for the Error Message. The Error parameter value can be one of the following values: Invalid Version 0x01 Invalid Network Identifier 0x02 Unexpected Message Class 0x03 Invalid Message Type 0x04 Unsupported Traffic Handling Mode 0x05 Unexpected Message 0x06 Protocol Error 0x07 Reserved 0x08 Invalid Stream Identifier 0x09 The "Invalid Version" error would be sent if a message was received with an invalid or unsupported version. The Error message would contain the supported version in the Common header. The Error message could optionally provide the supported version in the Diagnostic Information area. Loughney, et al. [Page 44] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The "Invalid Interface Identifier" error would be sent by a SG if an ASP sends a message with an invalid (unconfigured) Interface Identifier value. The "Unsupported Traffic Handling Mode" error would be sent by a SG if an ASP sends an ASP Active with an unsupported Traffic Handling Mode. An example would be a case in which the SG did not support load-sharing. The "Unexpected Message" error would be sent by an ASP if it received a message while it was in the Inactive state. The "Protocol Error" error would be sent for any protocol anomaly (i.e. a bogus message). The "Invalid Stream Identifier" error would be sent if a message was received on an unexpected SCTP stream (i.e. a stream that did not have an Interface Identifier associated with it). The "Unexpected Message Class" error would be sent if a message with an unexpected or unsupported Message Class is received. The optional Diagnostic information can be any information germane to the error condition, to assist in identification of the error condition. To enhance debugging, the Diagnostic information could contain the first 40 bytes of the offending message. The Cause parameter can be one of the following values: Invalid Version 0x1 Invalid Network Appearance 0x2 Invalid Adaptation Layer Identifier 0x3 Invalid Message Type 0x4 Invalid Traffic Handling Mode 0x5 Unexpected Message Type 0x6 Protocol Error 0x7 Invalid Routing Context 0x8 Unsupported Message Type 0x9 3.8.12 Status The Status Type parameter identifies the type of the status that is being notified. 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 Type | Status ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 45] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The valid values are shown in the following table. 1 Application Server state change (AS_State_Change) 2 Other The Status Id parameter identifies the status that is being notified. The valid values are shown in the following table. If the Status Type is AS_STATE_CHANGE If the Status Type is AS_State_Change the following Status Information values are used: 1 Application Server Down (AS_Down) 2 Application Server Up (AS_Up) 3 Application Server Active (AS_Active) 4 Application Server Pending (AS_Pending) 5 Alternate ASP Active 6 Insufficient ASPs If the Status Type is Other, then the following Status Information values are defined: 1 Insufficient ASP resources active in AS This notification is not based on the SG reporting the state change of an ASP or AS. For the value defined the SG is indicating to an ASP(s) in the AS that another ASP is required in order to handle the load of the AS. 3.9 SUA-Specific parameters These TLV parameters are specific to the SUA protocol. Parameter Name Parameter ID ============== ============ Sequence Number 0x0101 Source Address 0x0102 Destination Address 0x0103 Return Cause 0x0104 Flags 0x0105 Source Reference Number 0x0106 Destination Reference Number 0x0107 Reserved 0x0108 SCCP Error 0x0109 ASP Capabilities 0x010A Status 0x010B Credit 0x010C Not used 0x010D SMI / Subsystem 0x010E Loughney, et al. [Page 46] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 3.9.1 Sequence Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Rec Seq Num | Sent Seq Num | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ It is used exclusively for protocol class 3 to number each DT message sequentially for the purpose of flow control, sequence numbering and segmenting and reassembly. It is used to number each DT message sequentially for the purpose of flow control. It contains the received as well as the sent sequence number, P(R) and P(S) in Q.713. As such it can be used to acknowledge the receipt of data transfers from the peer in case of protocol class 3. Sent Sequence Number is one octet and is coded as follows: Bits 8-2 are used to indicate the Send Sequence Number P(S). Bit 1 of octet 1 is spare. Receive Sequence Number is one octet, and is coded as follows: Bits 8-2 are used to indicate the Receive Sequence Number P(R). Bit 1 is used for the more data indication, as follows: 0 no more data 1 more data. 3.9.2 Source Address (=CLG) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 47] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The Type of Address field is used to aid in the identification of the type of address. If this field is set to 0, then the address field needs to be analyzed. Type of Address Unknown/Undeterminable 0x00000000 SS7 SCCP CLG 0x00000001 Host Name 0x00000002 IPv4 Address 0x00000003 IPv6 Address 0x00000004 The combinations of SS7 addressing schemes (ITU, ANSI, etc). supported is implementation dependant. The Source Address field can contain the SCCP Calling Party Address. It is possible to simply encapsulate the information, as presented by the upper layer. 3.9.3 Destination Address (=CLD) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Routing param | Address Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / address parameter(s) / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The following address combinations are valid: 0x00 Reserved 0x01 Global Title 0x02 Global Title + PC 0x03 Global Title + PC + SSN 0x04 PC + SSN 0x05 Hostname 0x06 Hostname + SSN 0x07 IPv4 0x08 IPv4 + SSN 0x09 IPv6 0x0A IPv6 + SSN 3.9.3.1 Fixed Parameters Loughney, et al. [Page 48] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Routing parameter +-+-+-+-+-+-+-+-+ | |A|B|C|D| +-+-+-+-+-+-+-+-+ A : Routing indicator: 0x0 = route-on-Global Title / Name 0x1 = route-on-SSN B : SSN present : 0x0 = no SSN present 0x1 = SSN present C : Pointcode present: 0x0 = no pointcode present 0x1 = pointcode present D : GT/Name present : 0x0 = no Global Title/Name present 0x1 = Global Title/Name present The following combinations of B, C and D are valid: B | C | D | ----+-----+------+ 0 | 0 | 1 | (1) 1 | 1 | 1 | (2) 1 | 1 | 0 | (3) (1) only Global Title/name present, the output of the GTT function must yield a SSN in addition to the DPC. (2) GT, PC and SSN present, which of the elements to use for routing is determined by the routing indicator (3) PC and SSN present, routing indicator must be route-on-SSN Address tags: 0x00 Reserved 0x01 Global Title 0x02 PC 0x03 SSN 0x04 IPv4 0x05 Hostname 0x09 IPv6 3.6.3.2 Global Title 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= GLOBALTITLE | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GTI | Trans. type |E| Num. Plan | Nature of Add | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Global Title | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 49] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 GTI = 0: No parameters required. GTI = 1: Num Plan: Not Used Odd/even Indicator: 0 Even number of address signals 1 Odd number of address signals Nature of Address: 0 unknown 1 subscriber number 2 reserved for national use 3 national significant number 4 international number 5 - 255 Spare Global Title: Octets contain a number of address signals and possibly a filler as shown: 0 1 2 3 4 5 6 7 +---+---+---+---+---+---+---+---+ | 2nd addr.sig. | 1st addr.sig. | +---+---+---+---+---+---+---+---+ | 4th addr.sig. | 3rd addr.sig. | +---+---+---+---+---+---+---+---+ | ... | +---+---+---+---+---+---+---+---+ | filler(if req)| nth addr.sig. | +---+---+---+---+---+---+---+---+ Address signals to be coded as defined in ITU-T Q.713 Section 3.4.2.3.1. GTI = 2: (This type is for National use only) Translation Type: Since the allocation of Translation types for GTI=2 is a national matter, the values used should map directly onto the SCCP values (0 - 225). For North America, Translation type code values are listed in GR-246-CORE Ch. T1.112.3 Annex A. Global Title: as for GTI = 1 Loughney, et al. [Page 50] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 GTI = 3: Numbering Plan: Not Used Nature of Address: Not Used Translation Type: For GTI=3 (ANSI GTI=1) the Translation type coding is for further study. E = Odd/even Indicator 0 Even number of address signals 1 Odd number of address signals Numbering Plan: 0 unknown 1 ISDN/telephony numbering plan (Recommendations E.163 and E.164) 2 generic numbering plan 3 data numbering plan (Recommendation X.121) 4 telex numbering plan (Recommendation F.69) 5 maritime mobile numbering plan (Recommendations E.210, E.211) 6 land mobile numbering plan (Recommendation E.212) 7 ISDN/mobile numbering plan (Recommendation E.214) 8 - 13 spare 14 private network or network-specific numbering plan 15 - 126 spare 127 reserved. Global Title: as for GTI = 1 GTI = 4: Translation type: 0 Unknown 1 - 63 international services 64 - 127 spare 128 - 254 national network specific 255 reserved E and Numbering Plan: as for GTI = 3 Nature of Address: as for GTI = 1 Global Title: as for GTI = 1 Loughney, et al. [Page 51] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 3.6.3.2 Hostname 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TAG= HostName | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Host Name | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ If the type of address is Host Name, then the labels in the host name has to be reversed to obtain a efficient Host Name encoding form for the Global title translation function. hostname: zzzz.yyy....edc.ab should be transformed to HTname : ab.edc....yyy.zzzz The labels of the Host Name are then encoded using the encoding rules of the labels described in [IDNS]. The end of the Host name is indicated by 0x00. Example : hostname = www.reindael.security.org First the name has to be reverse to have the gTLD on the left side. Global Title name: org.security.reindael.www Then the result of applying the rules of the iDNS is: +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x | 3 | O | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+2 | R | G | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+4 | 7 | S | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+6 | E | C | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+8 | U | R | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+10| I | T | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+12| Y | 8 | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+14| R | E | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+16| I | N | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+18| D | A | Loughney, et al. [Page 52] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+20| E | L | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+22| 3 | W | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+24| W | W | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | 00 | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ 3.6.3.3 IP Addresses The IP address formats can use different tags. It should be noted that if the called is in a certain IP version ,the calling should also be in the same IP version. CLD = Ipv6, thus CLG must be = Ipv6 and vice versa. 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= IPvx | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IP Address | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.6.3.4 Subsystem number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TAG= SSN | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSN value | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.9.4 Return Cause The Return Cause corresponds to the return cause of the SCCP 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 = 0x0104 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 53] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The Length is a one octet unsigned integer. Possible values for the Return Cause are: 0x00 no translation for an address of such nature 0x01 no translation for this specific address 0x02 subsystem congestion 0x03 subsystem failure 0x04 unequipped user 0x05 MTP failure 0x06 network congestion 0x07 unqualified 0x08 error in message transport (Note) 0x09 error in local processing (Note) 0x0A destination cannot perform reassembly (Note) 0x0B SCCP failure 0x0C hop counter violation 0x0D segmentation not supported 0x0E segmentation failure 0xFA Invalid ISNI routing request (Note) 0xFB Unauthorized message 0xFC Message Incompatibility 0xFD Cannot perform ISNI Constrained routing (Note) 0xFE Redundant ISNI constrained routing information (Note) 0xFF Unable to perform ISNI identification (Note) NOTE: Only applicable to XUDT(S) message. 3.9.5 Flags 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | trans. type | Hop Counter | segmenting |D| B |A| C | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A Error Return option Value Description 0x0 No error message 0x1 Return message on error B Protocol class Value Description 0x0 Class 0 (connectionless service) 0x1 Class 1 (connectionless service) 0x2 Class 2 (connection-oriented service) 0x3 Class 3 (connection-oriented service Loughney, et al. [Page 54] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 C Importance Value Description 0x0 Least important : 0x7 Highest importance D Segmentation Value Description 0x0 No segmentation 0x1 Segmentation Transfer Type is used when either a SG or ASP has knowledge about the type of data transfer to send. If unable to determine which type is needed, a value of undetermined is used. The field has following values: 0 undetermined 1 unitdata 2 long unitdata 3 extended unitdata Hop Counter Value Description 0x0 : 0x15 Maximum number of GTT Segmenting field corresponds to the SCCP Segmenting parameter. 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ | segmenting | +-+-+-+-+-+-+-+-+ Bit 7 is coded as the following: _ 0: in all segments but the first; _ 1: first segment. Bit 6 is used to keep in the message in sequence delivery option required by the SCCP user and is coded as follows: _ 0: Class 0 selected; _ 1: Class 1 selected. Bits 4 and 5 are spare bits. Loughney, et al. [Page 55] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Bits 0-3 of octet 1 are used to indicate the number of remaining segments. The values 0000 to 1111 are possible; the value 0000 indicates the last segment. An SUA-layer MUST support receiving segmented messages & MUST be able to re-assembled segmented messages. An SUA-layer at an SG MUST be able to segment SCCP messages destined for the SS7 network. An SUA-layer at an IPSP MAY support sending segmented messages. 3.9.6 Source Reference Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The source reference number is a 3 octet long integer, which is generated by the local source to identify a connection. Valid values are from 0x0 to 0xFFFFFE, while 0xFFFFFF is reserved for future use. 3.9.7 Destination Reference Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Destination Reference Number is a 3 octet long integer, which is generated by the destination node to identify a connection. Valid values are from 0x0 to 0xFFFFFE, while 0xFFFFFF is reserved for future use. 3.9.8 SCCP 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 = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Cause Type | Cause Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 56] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Cause Type can have the following values: Return Cause 0x1 Refusal Cause 0x2 Release Cause 0x3 Reset Cause 0x4 Error Cause 0x5 Cause Value contains the specific error value. Below gives examples for ITU SCCP values. ANSI references can be found in ANSI T1.112.3 Cause value in Correspondence with Reference SUA message SCCP parameter ------------------ ----------------- --------- CLDR Return Cause ITU-T Q.713 Chap 3.12 COREF Refusal Cause ITU-T Q.713 Chap 3.15 RELRE Release Cause ITU-T Q.713 Chap 3.11 RESRE Reset Cause ITU-T Q.713 Chap 3.13 ERR Error Cause ITU-T Q.713 Chap 3.14 3.9.9 ASP Capabilities This parameter is used so that the ASP can report it's capabilities for supporting different protocol classes and interworking scenarios. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Variant |0 0 0 0|a|b|c|d| interworking | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The length is two octets. SCCP Variant field can contain the following values: Unidentified/unknown 0x0 ITU-I SCCP 0x1 ITU-N SCCP 0x2 ANSI SCCP 0x3 Japanese SCCP 0x4 Chinese SCCP 0x5 Other 0x6 Flags a - Protocol Class 3 b - Protocol Class 2 c - Protocol Class 1 Loughney, et al. [Page 57] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 d - Protocol Class 0 0 indicates no support for the Protocol Class. Interworking Values 0x0 indicates no interworking with SS7 Networks. 0x1 indicates IP Signaling Endpoint. 0x2 indicates Signaling Gateway. 3.9.10 Credit 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010C | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The length is one octet. 3.9.11 SCMG Message Type 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010D | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCMG Message Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The SCMG Message Type field may have the following values: 0 Reserved 1 SSA 2 SSP 3 SST 4 SOR 5 SOG 6 SSC 7 - 252 Reserved 253 SNR 254 SBR 255 SRT 3.9.12 SMI / Subsystem 0 1 2 3 Loughney, et al. [Page 58] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMI | Spare | SSN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Subsystem Number (SSN) is one octet. Subsystem multiplicity indicator (SMI) can have the following values: 0x00 Reserved 0x01 Replicated 0x02 Solitary 0x03 Unknown 3.9.13 Receive Sequence Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010F | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Rec Seq Num | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ It is used exclusively for protocol class 3 in the data acknowledgment message to indicate the lower edge of the receiving window. It is a 1 octet long integer coded as follows: Bits 8-2 are used to indicate the Receive Sequence Number P(R). Bit 1 is spare. 4 Procedures The SUA layer needs to respond to various local primitives it receives from other layers as well as the messages that it receives from the peer SUA layers. This section describes the SCU procedures in response to these events. 4.1 Peer Message Procedures On receiving a message, the SUA layer at the SG performs address translation and mapping (if needed), to determine the appropriate Application Server Process (ASP). The appropriate ASP can be determined based on the routing information in the incoming message, local load sharing information, etc. The appropriate SUA message is Loughney, et al. [Page 59] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 then constructed and sent to the appropriate endpoint, via the correct SCTP association. 4.1.1 Connection Oriented Timers The SUA layer needs to start a timer after sending a CR, RLSD or RSR message. 4.2 Signaling Gateway Related Procedures These support the SUA transport of SCCP-User/SCCP boundary primitives. On receiving a SCCP message at the SG, the SUA layer performs address translation and mapping, to determine the appropriate Application Server Process (ASP). The appropriate ASP can be determined based on the information in the incoming message, local load sharing information, etc. The appropriate SUA message is then constructed and sent to the appropriate endpoint, via the correct SCTP association. The SUA needs to setup and maintain the appropriate SCTP association to the selected endpoint. SUA also manages the usage SCTP streams. 4.2.1 ASP Down The SG maintains the availability of the remote ASPs, and will need to issue the correct SCCP management message (where applicable) to the SS7 node(s). ASPDN or even an ASPIA may not correlate to a SCCP SSP, as it depends upon the ASP load configuration (primary/backup or loadsharing specified in the routing context 'type' field) and also upon the ASP routing configuration. Where traffic for a single SSN is routed to just one ASP then the withdrawal of that ASP will result in a SSP being issued. By contrast, where a SSN is associated with more than one ASP and routing to the different ASPs is achieved using the routing context (e.g. TCAP TIDs) then the withdrawal of just one ASP will not yield a SSP message. 4.2.2 MTP 3 - SUA interaction The Signaling Gateway will need to manage the availability of the ASPs within the IP network; while reporting the status of endpoints in the SS7 network. Therefore, there will be interworking between the MTP 3 layer and SUA. MTP 3 indication messages (MTP Pause, MTP resume, MPT Status) need to be indicated to the peer SUA layer. Loughney, et al. [Page 60] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 4.2.3 Support of Connectionless Data Transfer When SUA operates in an interworking scenario with traditional SS7 networks, the SG (interworking function between SCCP and SUA) must ensure that the selected outgoing connectionless message type (UDT/S, XUDT/S or LUDT/S) is correctly understood by the recipient SCCP node. The criteria for message type selection shall be handled locally; this information can be based on the underlying MTP or remote SCCP capabilities, or selected messages types preferred by the recipient SCCP node. 4.3 Layer Management Procedures The SUA layer needs to send and receive layer management messages. 4.4 SCTP Management Procedures These procedures support the SUA management of SCTP Associations and ASP Paths between SGs and ASPs. 4.4.1 State Management The SUA layer on at each AS needs to maintain the state of each ASP under its control, as a way to manage the state and connections of the local ASPs. At a SG, the state of each ASP is needed as input to the SGs address translation and mapping function. 4.4.1.1 ASP States The state of each ASP is maintained in the SUA layer at the controlling AS. The state of an ASP changes due to events. The events include: * Reception of messages from that ASP's SUA layer * Reception of messages from a different ASP's SUA layer * Reception of indications from the SCTP layer * Switch over timer triggers The ASP state transition diagram is shown in Figure 4. The possible states of an ASP are: ASP-DOWN: The Application Server Process is unavailable. Initially all ASPs will be in this state. ASP-UP: The Application Server Process is available but application traffic is stopped. ASP-ACTIVE: The Application Server Process is available and application traffic is active. Loughney, et al. [Page 61] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Figure 4: ASP State Transition Diagram +-------------+ | | +----------------------| ASP-ACTIVE | | | | | +-------------+ | ^ | | ASP | | ASP | Active | | Inactive | | v | +-------------+ | | | | | ASP-UP |-------------+ | +-------------+ | | ^ | | ASP Down | ASP | | ASP Down / | ASP SCTP Down| Up | | SCTP Down | Down/ | | v | SCTP | +-------------+ | Down | | | | +--------------------->| ASP-DOWN |<------------+ | | +-------------+ Figure 4: ASP State Transition Diagram SCTP Down: The local SCTP layer's SHUTDOWN COMPLETE notification or COMMUNICATION LOST notification. 4.4.1.2 AS States The state of the AS is maintained in the SUA layer. The state of an AS changes due to events. These events include: * ASP state transitions * Recovery timer triggers The possible states of an AS are: AS-DOWN: The Application Server is unavailable. This state implies that all related ASPs are in the ASP-DOWN state for this AS. Initially the AS will be in this state. AS-UP: The Application Server is available but no application traffic is active (i.e., one or more related ASPs are in the ASP-UP state, but none in the ASP-Active state). Loughney, et al. [Page 62] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 AS-ACTIVE: The Application Server is available and application traffic is active. This state implies that one ASP is in the ASP- ACTIVE state. AS-PENDING: An active ASP has transitioned from active to inactive or down and it was the last remaining active ASP in the AS. A recovery timer T(r) will be started and all incoming SCN messages will be queued by the SG. If an ASP becomes active before T(r) expires, the AS will move to AS-ACTIVE state and all the queued messages will be sent to the active ASP. If T(r) expires before an ASP becomes active, the SG stops queuing messages and discards all previously queued messages. The AS will move to AS-UP if at least one ASP is in ASP-UP state, otherwise it will move to AS-DOWN state. +----------+ one ASP trans to ACTIVE +-------------+ | |---------------------------->| | | AS-UP | | AS-ACTIVE | | |<--- | | +----------+ \ +-------------+ ^ | \ Tr Expiry, ^ | | | \ at least one | | | | \ ASP in UP | | | | \ | | | | \ | | | | \ | | one ASP | | all ASP \ one ASP | | Last ACT. trans | | trans to \ trans to | | asp trans to UP | | DOWN -------\ ACTIVE | | to UP or | | \ | | DOWN | | \ | | | | \ | | | | \ | | | v \ | v +----------+ \ +-------------+ | | --| | | AS-DOWN | | AS-PENDING | | | | (queueing) | | |<----------------------------| | +----------+ Tr Expiry no ASP +-------------+ in UP state Tr = Recovery Timer Figure 5: AS State Transition Diagram 4.4.2 ASPM procedures for primitives Loughney, et al. [Page 63] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Before the establishment of an SCTP association the ASP state at both the AS and ASP is assumed to be "Down". When the SUA layer receives an M-SCTP ESTABLISH request primitive from the Layer Management, the SUA layer will try to establish an SCTP association with the remote SUA peer. Upon reception of an eventual SCTP-Communication Up confirm primitive from the SCTP, the SUA layer will invoke the primitive M-SCTP ESTABLISH confirm to the Layer Management. Alternatively, if the remote SUA-peer establishes the SCTP association first, the SUA layer will receive an SCTP Communication Up indication primitive from the SCTP. The SUA layer will then invoke the primitive M-SCTP ESTABLISH indication to the Layer Management. Once the SCTP association is established, The SUA layer at an ASP will then find out the state of its local SUA-user from the Layer Management using the primitive M-ASP STATUS. Based on the status of the local SUA-User, the local ASP SUA Application Server Process Maintenance (ASPM) function will initiate the ASPM procedures, using the ASP-Up/-Down/-Active/-Inactive messages to convey the ASP-state to the SG - see Section 2.5. If the SUA layer subsequently receives an SCTP-Communication Down indication from the underlying SCTP layer, it will inform the Layer Management by invoking the M-SCTP STATUS indication primitive. The state of the ASP will be moved to "Down." At an ASP, the Layer Management may try to reestablish the SCTP association using M-SCTP ESTABLISH request primitive. 4.4.3 ASPM procedures for peer-to-peer messages 4.4.3.1 ASP-Up An ASP sends an ASPUP to each remote AS to which it is a member of. When the ASPUP message is received, the remote AS will mark the remote ASP Inactive, as long as the ASP is not considered locked-out for local management reasons. The remote peer replies with an ASP- Up Ack message in acknowledgement, to every ASPUP, even if the ASP is already marked as Inactive. If for any local reason (e.g., management lock-out) the remote peer cannot respond with an ASP-Up Ack, the SG responds to an ASP-Up with an ASP-Down Ack message with Reason "Management Blocking". If the ASP does not receive a ASPUP ACK, the ASP may resend ASP-Up messages until it receives an ASP-Up Ack message. The ASP must wait for the ASP-Up Ack message before sending any other messages. If the Loughney, et al. [Page 64] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 remote peer receives any other SUA messages from an ASP, before an ASP Up is received, the message should be discarded. 4.4.3.2 ASP Down The AS will mark the ASP as down and send a ASPDN message to the ASP if one of the following events occur: - an ASP Down (ASPDN) message is received from the ASP, - the ASP is locked by local maintenance. The SG sends an ASP-Down Ack message in response to a received ASP- Down message from the ASP even if the ASP is already marked as Down. The ASP will send ASPDN whenever it wants to take down a ASP. Since it is possible for ASPDN and ASPDN ACK messages to be lost (for example, during a node failover), the ASP can send ASPDN messages every t(a) seconds until the path comes down (i.e. until it receives a ASPDN message from the remote peer for that path). 4.4.3.3 ASP Version Control If a ASP Up message with an unknown version is received, the receiving end will respond with an Error message. This will indicate to the sender which version the receiving node supports. This is useful when protocol version upgrades are being performed. A node with the newer version should support the older versions used on other nodes it is communicating with. The version field in the Error message header associated will indicate the version supported by the node. 4.4.3.4 ASP Active When an ASP is ready to start processing traffic, it sends an ASP Active message to the remote peer. When an ASP Active (ASPAC) message is received, the remote peer responds with an ASPAC ACK. The ASP cannot send any other messages until after the ASPAC ACK is received. If the ASPAC ACK is not received within a certain period, the ASP may resend the ASPAC message. The ASP Active message optionally contains a list of one more Routing Contexts, indicating for which Application Servers the ASP is joining. If no Routing Contexts are present, then local configuration data is used to determine to which Application Server(s) the ASP belongs. The Type parameter in the ASPAC message indicates the traffic handling mode used in a particular Application Server, either Over- Loughney, et al. [Page 65] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 ride, Over-ride (standby), Load-share or Load-share (standby). If the remote peer determines that the mode indicated in an ASPAC is incompatible with the mode currently used in the AS, the remote peer responds with an Error message indicating "Invalid Traffic Handling Mode". In the Over-ride mode, reception of an ASPAC message at a remote peer causes the all traffic for the AS to be sent to the ASP which sent the ASPAC. All previously active ASPs in the AS are now considered Inactive and will no longer receive traffic for that particular AS. The remote peer sends a Notify (Alternate ASP- Active) to the previously active ASPs in the AS, after stopping all traffic to that ASP. In the Over-ride (Standby) mode, the actions are the same with the exception that the traffic is not started to the ASP until the previously active ASP transitions to "Inactive or "Down" state. At this point the ASP that sent the Over-Ride (Standby) ASPAC is moved to the Active state and the traffic is redirected. No Notify messages are needed. In the Load-share mode, reception of an ASPAC message causes the redistribution of traffic to the ASP sending the ASPAC, in addition to all the other ASPs that are currently active in the AS. The algorithm at the SG for load-sharing traffic within an AS to all the active ASPs is implementation dependent. All ASPs marked load- sharing should be able to handle any traffic within the AS, in order to accommodate any potential fail-over or re-balancing of the offered load. In the Load-share (Standby) mode, the actions are the same as the Load-share mode, with the exception that the traffic is not started to the ASP until the remote peer determines that additional resources are needed the AS. When needed, the ASP which sent the Loadshare (Standby) ASPAC is moved to the Active state and traffic is started. No Notify messages are needed to be sent. A node that receives an ASPAC with an incorrect Type for a particular Routing Context will respond with an Error Message, Cause = Invalid Traffic Handling Mode. A node that receives an unknown Routing Context value responds with an Error message, Cause = Invalid Routing Context. 4.4.3.5 ASP Inactive When an ASP wishes to withdraw from receiving traffic, it sends an ASPIA to the applicable remote ASPs, within the AS from which it is withdrawing. If the ASP is withdrawing from more than one AS, then the ASP issues either multiple ASPIA message, if multiple SCTP Loughney, et al. [Page 66] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 associations exist to the remote ASPs; or a single ASPIA message containing multiple Routing Contexts. There are two ASPIA modes, Over-ride and load-share. If the remote peer determines that the Type parameter in the ASPIA is inconsistent with the mode being used by the Application Server, an error is reported to the local layer management, Invalid Traffic Handling Mode. However, the ASPIA is still handled. In the Over-ride mode, the ASP which sent the ASPIA is marked as Inactive. No further traffic is sent from and to the ASP marked Inactive. In the Load-sharing mode, the remote AS marks the ASP as inactive and re-allocates the traffic to the remaining active ASPs. The load-sharing mechanism used is outside of the scope of SUA. If there is insufficient resources, a NTFY (Insufficient ASPs) may be sent to all inactive ASPs. If a Loadshare (Standby) ASP is available, it may be now immediately included in the loadshare group and a Notify message may not be sent. An ASPIA Ack message is sent to the ASP after all traffic is halted. In the case when no other ASPs are active or standby in the Application Server, the remote peer should send a NTFY (AS-Pending) to all inactive ASPs of the AS. The remote peer then either discards all incoming messages for the AS or starts buffering the incoming messages for T(r) seconds, after which messages will be discarded. T(r) is configurable by the network operator. If the remote peer receives an ASPAC from an ASP in the AS before expiry of T(r), the buffered traffic is directed to the ASP and the timer is cancelled. If T(r) expires, the AS is moved to the "Down" state. 4.4.3.6 Notify A NTFY message reflecting a change in the AS state is sent to all ASPs in the AS, except those in the "Down" state, with appropriate Status Identification. In the case where a NTFY (AS-Pending) message is sent by an SG that now has no ASPs active to service the traffic, or a NTFY Insufficient ASPs) is sent in the Loadshare mode, the NTFY does not explicitly force the ASP(s) receiving the message to become active. The ASPs remain in control of what (and when) action is taken. 4.3.3.7 Heartbeat Loughney, et al. [Page 67] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The optional Heartbeat message may be sent in order to query the status of the remote peer. It is optional to send, but mandatory to acknowledge. The data field can be used to store information in the heartbeat message useful to the sending node (e.g. the data field can contain a time stamp, a sequence number, etc.). 5 Examples of SUA Procedures The following sequence charts overview the procedures of SUA. These are meant as examples, they do not, in and of themselves, impose additional requirements upon an instance of SUA. 5.1 SG Architecture The sequences below outline logical steps for a variety of scenarios within a SG architecture. Please note that these scenarios cover a Primary/Backup configuration. Where there is a load-sharing configuration then the SG can declare availability when 1 ASP issues ASPAC but can only declare unavailability when all ASPs have issued ASPIA. 5.1.1 Establishment of SUA connectivity The following must be established before SUA/SCCP traffic can flow. Each node is configured (via MIB or through discovery protocol) with the connections that need to be setup ASP-a1 ASP-a2 SG SEP (Primary) (Backup) |------Establish SCTP Association------| |--Estab. SCTP Ass--| |--Align SS7 link---| Each ASP declares to the SG that it is running. +----------------ASP Up----------------> <--------------ASP Up Ack--------------+ +------ASP Up-------> <---ASP Up Ack------+ The Primary ASP declares to the SG that it is active. The SG notifies all ASPs. +-------------ASP Active---------------> <----------ASP Active Ack--------------+ <----------NTFY (ASP Active)-----------+ <-NTFY (ASP Active)-+ Loughney, et al. [Page 68] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The SG declares the availability of the signaling user on ASP-a1 to the SEP. The SG has been configured (via a MIB) that the SEP is concerned about its signaling users. N.B. The SGs SS7 address is presented in the SSA, i.e. the SG represents the availability of ASP-a1 to the SEP. +--------SSA--------> The SEP declares its availability to the SG since the SG appears within its concerned list. Similarly, the SG informs the active ASP of the availability of the SEP as dictated by SGs concerned list. N.B. The SG maps the SS7 address of the SEP to an IP address which the SG knows ASP-a1 will understand. <--------SSA--------+ <-----------------DAVA-----------------+ Traffic can now flow. A connectionless flow is shown for simplicity. Nevertheless, the SG is responsible for mapping IP to SS7 addresses and vice-versa. Only the Routing Context for ASP-a1 persists from ASP-a1 to SEP. +-----------------CLDT-----------------> +--------UDT--------> 5.1.2 Failover scenarios The following sequences address failover of SEP and ASP 5.1.2.1 SEP Failover The SEP knows that the SG is 'concerned' about its availability. Similarly, the SG knows that ASP-a1 is concerned about the SEPs availability, therefore the incoming SSP is translated into DUNA. ASP-a1 can then instruct the SG to invoke the SS7 Sub-system Test procedure using AUD. ASP-a1 ASP-a2 SG SEP (Primary) (Backup) <--------SSP--------+ <-----------------DUNA-----------------+ +-----------------DAUD-----------------> +--------SST--------> 5.1.2.2 Successful ASP Failover scenario Loughney, et al. [Page 69] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The following is an example of a successful failover scenario, where there is a failover from ASP-a1 to ASP-a2, i.e. Primary to Backup. During the failover, the SG buffers any incoming data messages from the SEP, forwarding them when the Backup becomes available. ASP-a1 ASP-a2 SG SEP (Primary) (Backup) +-------------ASP Inactive-------------> <----------NTFY (ASP Inactive)---------+ <-NTFY (ASP Inact.)-+ +----ASP Active-----> <--ASP Active Ack---+ <-NTFY (ASP Active)-+ <----------NTFY (ASP Active)-----------+ 5.1.2.3 Unsuccessful ASP Failover scenario ASP-a1 ASP-a2 SG SEP (Primary) (Backup) +-------------ASP Inactive-------------> <----------NTFY (ASP Inactive)---------+ <-NTFY (ASP Inact.)-+ After some time elapses (i.e. timeout). +--------SSP--------> <--------SST--------+ 5.2 IP-IP Architecture The sequences below outline logical steps for a variety of scenarios within an IP-IP architecture. Please note that these scenarios cover a Primary/Backup configuration. Where there is a load-sharing configuration then the AS can declare availability when 1 ASP issues ASPAC but can only declare unavailability when all ASPs have issued ASPIA. 5.2.1 Establishment of SUA connectivity The following shows an example establishment of SUA connectivity. In this example, each IP SP consists of a Management Instance (MI) and two ASPs. The Management Instance handles the address mapping mechanisms and monitors the states of the remote peer. For simplicity, the Management Instances and ASPs are considered as a separate entity. This is not a requirement, as they can be co- located with an ASP. The following must be established before SUA traffic can flow. A connectionless flow is shown for simplicity. Loughney, et al. [Page 70] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Each node is configured (via MIB or through discovery protocol) with the connections that need to be setup IP SEP A IP SEP B ASP-a1 ASP-a2 MI a MI b ASP-b2 ASP-b1 (Primary) (Backup) (Backup) (Primary) Establish SCTP Connectivity |-- Est. SCTP Ass.--| |------ Establish SCTP Association -------| |------------- Establish SCTP Association -------------| |------------------ Establish SCTP Association ------------------| |--- Establish SCTP Assoc. ----| |------- Establish SCTP Association --------| |------------ Establish SCTP Association -------------| |-- Establish SCTP Association -| |------- Establish SCTP Association ------| Establish SUA Connectivity +---------------ASP Up-------------------> <---------------ASP Up Ack---------------+ +------------ASP Up-----------> <------------ASP Up Ack-------+ <--------------ASP Up-------------+ +--------------ASP Up Ack---------> <----------------ASP Up---------------------+ +----------------ASP Up Ack-----------------> +---------------ASP Act------------------> <---------------ASP Act Ack--------------+ <----------------ASP Act--------------------+ +----------------ASP Act Ack----------------> Traffic can now flow directly between ASPs. +-------------------------------CLDT-------------------------------> 5.2.2 Failover scenarios Loughney, et al. [Page 71] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 The following sequences address failover of ASP 5.2.2.1 Successful ASP Failover scenario The following is an example of a successful failover scenario, where there is a failover from ASP-a1 to ASP-a2, i.e. Primary to Backup. Since data transfer passes directly between peer ASPs, ASP-b1 is notified of the failover of ASP-a1 and must buffer outgoing data messages until ASP-a2 becomes available. IP SEP A IP SEP B ASP-a1 ASP-a2 MI a MI b ASP-b2 ASP-b1 (Primary) (Backup) (Backup) (Primary) +--------------ASP Inact-----------------> <--------------ASP Inact Ack-------------+ <----NTFY (ASP-a1 Inactive)---+ +----------ASP Act------------> <----------ASP Act Ack--------+ 5.2.2.2 Unsuccessful ASP Failover scenario The sequence is the same as 4.2.2.1 except that, since the backup fails to come in then, the Notify messages declaring the availability of the backup are not sent. 6 Message Routing Scenarios 6.1 Basic case with single SG acting as end- or relay-point ______ _____ ______ | | SS7 | | IP | | | SEP |-----------| SG |-----------| ASP | |_____| |____| |_____| 6.1.1 SG as end-point Address information in (X)UDT message from SEP to SG : - MTP routing label OPC = SEP, DPC = SG - SCCP calling party address contains SSN, optionally OPC = SEP - SCCP called party address contains SSN At the SG, the SCCP subsystem identified by SSN (and for non- standardized SSN, also MTP network) is regarded as a local subsystem. From SEP point of view, the SCCP-user is located at the SG. Loughney, et al. [Page 72] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Depending on administration data, the SG knows the SCCP-user is serviced by an AS, which means a set of ASPs working in n+k redundancy mode. An ASP is selected and the CLDT message is sent on the appropriate SCTP association/stream. Actually, the primitive interface between SCCP and SCCP-user is transported here over SUA. Address information in CLDT message from SG to ASP : - Association ID : SG-ASP, Stream ID : based on SLS (and possibly OPC, MTP network ID) - Source address contains PC (SEP) + SSN + MTP network ID, needed for back routing - Destination address contains SSN, to select the SCCP-user at the ASP. The MTP network ID is needed if the SG operates in more than 1 MTP network. PC and SSN only have meaning within an MTP network. In the response, the ASP should pass a unique, unambiguous source address. Further messages from SEP belonging to the same transaction / connection will then reach the same ASP. Address information in CLDT message from ASP to SG : - Association ID : ASP-SG, Stream ID : implementation dependent, but in-sequence-delivery must be taken care of - Source address contains unique ASP address : when used as SCCP called party address at the SG, the SG SHOULD select the same ASP again. - Destination address copied from source address in received CLDT message. 6.1.2 SG as relay-point Address information in (X)UDT message from SEP to SG : - MTP routing label OPC = SEP, DPC = SG - SCCP calling party address contains SSN, optionally OPC = SEP, and a GT - SCCP called party address contains SSN and a GT Since routing is done on GT, the actual location of the SCCP-user is irrelevant to the SEP. Translation of the GT always leads to a "SCCP entity set", which in this case equals an AS. Selection of the AS is thus based on the SCCP called party address (and possibly other parameters, e.g. OPC, depending on the implementation). Basically this means splitting the SS7 traffic over different AS's based on GT information After this, the same as in 6.1.1 applies. Loughney, et al. [Page 73] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Address information in CLDT message from SG to ASP : - Association ID : SG-ASP, Stream ID : based on SLS (and possibly OPC, MTP network ID) - Source address contains PC (SEP) + SSN + MTP network ID or a GT, needed for back routing - Destination address contains SSN, to select the SCCP-user at the ASP. 6.2 Replicated SG acting as end-point ______ _____ | | | | | STP |------------| SG | |_____| |____| / \ / \ / \ / \ / \ / \ / \ / \ ______ / \ / \ ______ | | / \ / \| | | SEP |/ \ /| ASP | |_____|\ / \ / |_____| \ / \ / \ / \ / \ / \ / \ / \ / ______/ _____/ | | | | | STP |-----------| SG | |_____| |____| This case does not differ much from the basic case 6.1.1. The SCCP- user is still considered to be located at the SG. Only for the first message of the transaction/connection, a SG selection must be made (possibly via GTT at the STPs, or by implementation dependent means on the SEP). Once selected, the same SG is used throughout the transaction/connection. 6.3 Replicated SG acting as relay-point Loughney, et al. [Page 74] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 ______ _____ | | | | | STP |------------| SG | |_____| |____| / \ / \ / \ / \ / \ / \ / \ / \ ______ / \ / \ ______ | | / \ / \| | | SEP |/ \ /| ASP | |_____|\ / \ / |_____| \ / \ / \ / \ / \ / \ / \ / \ / ______/ _____/ | | | | | STP |-----------| SG | |_____| |____| The final GTT occurs in one of the mated pair SGs (with identical database). The ASP is selected in the same way as in 6.1.2. In normal circumstances, the path from SEP to ASP will always go via the same SG when in-sequence-delivery is requested. However, linkset failures may cause re-routing to the other SG. This should be kept in mind when the SG is to reassemble XUDT segments received from SEP into a single CLDT before sending to the ASP. 7 Security 7.1 Introduction SUA is designed to carry signaling messages for telephony services. As such, SUA must involve the security needs of several parties: the end users of the services; the network providers and the applications involved. Additional security requirements may come from local regulation. While having some overlapping security needs, any security solution should fulfill all of the different parties' needs. 7.2 Threats There is no quick fix, one-size-fits-all solution for security. As a transport protocol, SUA has the following security objectives: * Availability of reliable and timely user data transport. * Integrity of user data transport. * Confidentiality of user data. Loughney, et al. [Page 75] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 SUA runs on top of SCTP. SCTP provides certain transport related security features, such as: * Blind Denial of Service Attacks * Flooding * Masquerade * Improper Monopolization of Services When SUA is running in professionally managed corporate or service provider network, it is reasonable to expect that this network includes an appropriate security policy framework. The "Site Security Handbook" [2196] should be consulted for guidance. When the network in which SUA runs in involves more than one party, it may not be reasonable to expect that all parties have implemented security in a sufficient manner. End-to-end security should be the goal, therefore, it is recommended that IPSEC is used to ensure confidentiality of user payload. Consult [2409] for more information on configuring IPSEC services. 7.3 Protecting Confidentiality Particularly for mobile users, the requirement for confidentiality may include the masking of IP addresses and ports. In this case application level encryption is not sufficient; IPSEC ESP should be used instead. Regardless of which level performs the encryption, the IPSEC ISAKMP service should be used for key management. 8 IANA Considerations 8.1 SCTP Payload Protocol ID A request will be made to IANA to assign SCTP Payload Protocol IDs. A Payload ID for the SUA will be registered. The Payload ID is included in each SCTP data chunk, to indicate which protocol SCTP is carrying. This Payload ID is not directly used by SCTP but may be used by certain network entities to identify the type of information being carried in this DATA chunk. It is assumed that the Payload ID for SUA will be 4. 8.2 Port Number SUA will use port number 14001, which is currently registered to "ITU-T SCCP". This Port Number is the port which the SG listen to when receiving SCTP datagrams. Protocol Extensions This protocol may also be extended through IANA in three ways: Loughney, et al. [Page 76] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 -- through definition of additional message classes, -- through definition of additional message types, and -- through definition of additional message parameters. The definition and use of new message classes, types and parameters is an integral part of SIGTRAN adaptation layers. Thus, these extensions are assigned by IANA through an IETF Consensus action as defined in [RFC2434]. The proposed extension must in no way adversely affect the general working of the protocol. 8.3 IETF Defined Message Classes The documentation for a new message class MUST include the following information: (a) A long and short name for the message class; (b) A detailed description of the purpose of the message class. 8.3.1 IETF Defined Message Types Documentation of the message type MUST contain the following information: (a) A long and short name for the new message type; (b) A detailed description of the structure of the message. (c) A detailed definition and description of intended use of each field within the message. (d) A detailed procedural description of the use of the new message type within the operation of the protocol. (e) A detailed description of error conditions when receiving this message type. When an implementation receives a message type which it does not support, it MUST respond with an Error (ERR) message, with an Error Code = Unsupported Message Type. 8.3.3 IETF-defined TLV Parameter Extension Documentation of the message parameter MUST contain the following information: (a) Name of the parameter type. (b) Detailed description of the structure of the parameter field. This structure MUST conform to the general type-length-value format described earlier in the document. (c) Detailed definition of each component of the parameter value. (d) Detailed description of the intended use of this parameter type, and an indication of whether and under what circumstances multiple instances of this parameter type may be found within the same message type. Loughney, et al. [Page 77] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 9 Timer Values Ta 2 seconds Tr 2 seconds T(ack) 2 seconds 10 Acknowledgements The authors would like to thank Al Varney, Brian Bidulock, Marja- Liisa Hamalainen and Markus Maanoja for their insightful comments and suggestions. Funding for the RFC editor function is currently provided by the Internet Society. 10 Authors' Addresses John Loughney Nokia Research Center PO Box 407 FIN-00045 Nokia Group Finland EMail: john.loughney@nokia.com Greg Sidebottom Nortel Networks 3685 Richmond Rd, Nepean, Ontario, Canada K2H 5B7 EMail: gregside@nortelnetworks.com Guy Mousseau Nortel Networks 3685 Richmond Rd Nepean, Ontario, Canada K2H 5B7 Stephen Lorusso Unisphere Solutions One Executive Drive Chelmsford, MA 01824 USA email: SLorusso@UnisphereSolutions.com Lode Coene Siemens Atea Atealaan 34 B-2200 Herentals Belgium Phone: +32-14-252081 EMail: lode.coene@siemens.atea.be Loughney, et al. [Page 78] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Gery Verwimp Siemens Atea 34 Atealaan PO 2200 Herentals Belgium Phone : +32 14 25 3424 EMail:gery.verwimp@siemens.atea.be Joe Keller Tekelec 5200 Paramount Parkway Morrisville, NC 27560 USA EMail: joe.keller@tekelec.com Florencio Escobar Gonzalez Ericsson Spain S.A. Retama 7, 2nd floor 28045, Madrid Spain EMail: florencio.escobar@ericsson.com Steven Furniss Marconi New Century Park Coventry CV3 1HJ United Kingdom EMail: steven.furniss@marconi.com William Sully Marconi New Century Park Coventry CV3 1HJ United Kingdom EMail: william.sully@marconi.com 11 References [2719] RFC 2719, "Framework Architecture for Signaling Transport" [ITU SCCP] ITU-T Recommendations Q.711-714, 'Signaling System No. 7 (SS7) - Signaling Connection Control Part (SCCP)' [ANSI SCCP] ANSI T1.112 'Signaling System Number 7 - Signaling Connection Control Part' [ITU TCAP] ITU-T Recommendation Q.771-775 'Signaling System No. 7 SS7) - Transaction Capabilities (TCAP) Loughney, et al. [Page 79] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 [ANSI TCAP] ANSI T1.114 'Signaling System Number 7 - Transaction Capabilities Application Part' [RANAP] 3G TS 25.413 V3.3.0 (2000-09) 'Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRAN Iu Interface RANAP Signalling' [SCTP] RFC 2960 "Stream Control Transport Protocol" R. Stewart, et. Al. November 2000. [M3UA] MTP3-User Adaptation Layer , September 2000, Work in Progress. [2401] RFC 2401, "Security Architecture for the Internet Protocol", S. Kent, R. Atkinson, November 1998. [UTRAN IUR] 3G TS 25.420 V3.2.0 (2000-09) "Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRAN Iur Interface General Aspects and Principles" [2196] RFC 2196, "Site Security Handbook", B. Fraser Ed., September 1997. [ENUM] "ENUM Requirements" , June 2000, Work in Progress. [E.164-DNS] RFC 2916 "E.164 number and DNS", P. Faltstrom, September 2000. [IDNS] Blanchet, M., Hoffman, P., "Internationalized domain names using EDNS (IDNE)", , Work in progress, July 2000 [RFC2434] RFC 2434 "Guidelines for Writing an IANA Considerations Section in RFCs", T. Narten, H. Alvestrand, October 1998. [ITU-MTP] ITU-T Recommendations Q.701-Q.705, 'Signalling System No. 7 (SS7) - Message Transfer Part (MTP)' [ANSI-MTP] ANSI T1.111 'Signaling System Number 7 - Message Transfer Part' Appendix A: Message mapping between SCCP and SUA. This is for illustrative purposes only. SUA SCCP SCCP Classes Mgt. SUA Loughney, et al. [Page 80] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Name Name Full Name 0 1 2 3 Msg.Usage ==================================================================== Connectionless Messages CLDT UDT Unitdata X X - - - - CLDT XUDT Extended unitdata X X - - - - CLDT LUDT Long unitdata X X - - - - CLDR UDTS Unitdata service X X - - - - CLDR XUDTS Extended unitdata serv. X X - - - - CLDR LUDTS Long unitdata service X X - - - - Connection-Oriented Messages CODT DT1 Data form 1 - - X - - - CODT DT2 Data form 2 - - - X - - CODT ED Expedited data - - - X - - CODA AK Data acknowledgement - - - X - - CODA EA Expedited data ack. - - - X - - CORE CR Connection request - - X X - - COAK CC Connection confirm - - X X - - COAK CREF Connection refused - - X X - - RELRE RLSD Released - - X X - - RELCO RLC Release complete - - X X - - RESRE RSR Reset request - - - X - - RESCO RSC Reset confirm - - - X - - General Protocol Messages ERR ERR Protocol data unit error - - X X - X AUD IT Inactivity test - - X X - X SS7 MGT Messages DUNA n/a n/a - - - - - X DAVA n/a n/a - - - - - X DAUD n/a n/a - - - - - X SCMG SSC SCCP/subsystem-congested - - - - X - SCMG SSA subsystem-allowed - - - - X - SCMG SSP subsystem-prohibited - - - - X - SCMG SST subsystem-status-test - - - - X - SCMG SOR subsystem-oos-req - - - - X - SCMG SOG subsystem-oos-grant - - - - X - SUA MGT Messages ASPUP n/a n/a - - - - - X ASPDN n/a n/a - - - - - X ASPAC n/a n/a - - - - - X ASPIA n/a n/a - - - - - X NTFY n/a n/a - - - - - X - = Message not applicable for this protocol class. X = Message applicable for this protocol class. n/a = not applicable Loughney, et al. [Page 81] Internet Draft SS7 SCCP-User Adaptation Layer November 24, 2000 Appendix B: Message Mapping Examples 1 SUA->SCCP 2 SCCP->SUA CLDT - A and B flags are mapped from 'Protocol Class' parameter received in XUDT/LUDT/UDT (or from Data Request primitive). - C flag is mapped from 'Importance parameter' received in XUDT/LUDT (or from Data Request primitive), or if not present a default value for the message type shall be used. Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Loughney, et al. [Page 82]