INTERNET-DRAFT J. Loughney Internet Engineering Task Force Nokia G. Sidebottom, Guy Mousseau Issued: 1 February 2001 Nortel Networks Expires: 1 August 2001 S. Lorusso Unisphere Solutions L. Coene, 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 1 August 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 February 1, 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 .............................11 1.5 Internal Functions Provided in the SUA Layer ...................13 1.6 Definition of SUA Boundaries ...................................15 2 Conventions........................................................16 3 Protocol Elements..................................................16 3.1 Common Message Header ..........................................16 3.2 SUA Connectionless Messages ....................................19 3.3 Connection Oriented Messages ...................................21 3.4 SS7 Signaling Network Management Messages ......................29 3.5 Application Server Process Maintenance Messages ................34 3.6 ASP Traffic Maintenance Messages ...............................36 3.7 Management Messages ............................................39 3.8 Common Parameters ..............................................40 3.9 SUA-Specific parameters ........................................49 4 Procedures.........................................................62 4.1 SCCP _ SUA Interworking at the SG ..............................62 4.2 Primitives received from the local SUA-user ....................63 4.3 Layer Management Procedures ....................................64 4.4 SUA Management Procedures ......................................65 5 Examples of SUA Procedures.........................................71 5.1 SG Architecture ................................................71 5.2 IP-IP Architecture .............................................74 6 Message Routing Scenarios..........................................76 6.1 Basic case with single SG acting as end- or relay-point ........76 6.2 Replicated SG acting as end-point ..............................77 6.3 Replicated SG acting as relay-point ............................78 7 Security...........................................................79 7.1 Introduction ...................................................79 7.2 Threats ........................................................79 7.3 Protecting Confidentiality .....................................79 8 IANA Considerations................................................80 8.1 SCTP Payload Protocol ID .......................................80 8.2 Port Number ....................................................80 8.3 Protocol Extensions ............................................80 9 Timer Values.......................................................81 10 Acknowledgements..................................................81 10 Authors' Addresses................................................81 11 References........................................................83 Appendix A: Message mapping between SCCP and SUA.....................84 Copyright Statement..................................................85 Loughney, et al. [Page 2] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 Signaling Gateway Processes, which are 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 a virtual IP database element handling all request for a SCCP-user. The AS Loughney, et al. [Page 3] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 SS7 network ID and SCCP SSN for 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. In the case of SUA, the Routing Key should be limited to a combination of SS7 network ID and SCCP SSN to identify an AS, in order to more easily support SCCP management procedures. 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. Network Appearance - The Network Appearance identifies an SS7 network context (network ID) for the purposes of logically separating the signaling traffic between the SG and the Application Server Processes over a common SCTP Association. This partitioning is necessary where an SG is logically partitioned to appear as an end-node elements in multiple separate national SS7 networks, in which case there is a separate network appearance for each SS7 Loughney, et al. [Page 4] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 network. It is also necessary when an SG is configured as an STP and hosts multiple point codes within the same network, in which case each point code is a separate network appearance. 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. The first section considers the SS7-IP interworking architectures for connectionless and connection- oriented transport. For this case, it is assumed that the ASP initiates the establishment of the SCTP association with SG. 1.3.1 Protocol Architecture for Connectionless Transport In this architecture, the SCCP and SUA layers interface in the SG. There needs to be interworking between the SCCP and SUA layers to provide for the seamless transfer of the user messages as well as the management messages. For messages destined for an ASP, there are two scenarios. ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * Loughney, et al. [Page 5] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 * 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 1.3.1.1 SG as endpoint In this case, the connectionless SCCP messages are routed on PC and SSN. The subsystem identified by SSN and SS7 network appearance is regarded as local to the SG. This means from SS7 point of view, the SCCP-user is located at the SG. By means of configuration, the SG knows the local SCCP-user is actually representing an AS, serviced by a set of ASPs working in n+k redundancy mode. An ASP is selected and a CLDT message is sent on the appropriate SCTP association/stream. Actually, the primitive interface between SCCP and SCCP-user is transported here over SUA. An example for a INAP/TCAP message exchange between SEP and ASP is given below. Address information in CLDT message (TC_Query) from SG to ASP : - Association ID : SG-ASP, - Stream ID : based on SLS (and possibly OPC, SS7 network ID), - Network appearance : based on SS7 network ID, - Source address : valid combination of SSN, PC and GT, as needed for back-routing, - Destination address : at least SSN, to select the SCCP-user at the ASP. The Network Appearance is needed if the SG operates in more than one SS7 network, since PC and SSN only have meaning within a specific SS7 network. In the response, the ASP should pass a unique, unambiguous source address. Loughney, et al. [Page 6] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Address information in CLDT message (TC_Response) from ASP to SG : - Association ID : ASP-SG, - Stream ID : implementation dependent, but in-sequence- delivery must be taken care of, - Network appearance : as received in previous message, - Source address : unique ASP address that when used as SCCP called party address in the SEP, MUST yield the same ASP again; the SSN could be sufficient, - Destination address : copied from source address in received CLDT message. Further messages from the SEP belonging to the same TCAP transaction will now reach the same ASP. 1.3.1.2 SG as relay-point A Global Title translation must be executed at the SG, before the destination of the message can be determined. The actual location of the SCCP-user is irrelevant to the SS7 network. GT Translation yields an "SCCP entity set", which now may contain one or more AS. Selection of the AS is thus based on the SCCP called party address (and possibly other SS7 parameters 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 1.3.1.1 applies. 1.3.2 Protocol Architecture for Connection-Oriented Transport In this architecture, the SCCP and SUA layers interface in the SG to associate the two connection sections needed for the connection- oriented data transfer between SEP and ASP. Both connection sections are setup when routing the Connect Request messages from SEP via SG to ASP. The routing of the Connect Request message is done in the same wavy as described in 1.3.1. Further messages for this connection are routed on DPC in the SS7 connection section (MTP routing label), and on IP address in the IP connection section (SCTP header). No other routing information is present in the SCCP or SUA messages themselves. Resources are kept within the SG to forward messages from one section to another and to populate the MTP routing label or SCTP header, based on the destination local reference of these messages (Connect Confirm, Data Transfer, ...) ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * Loughney, et al. [Page 7] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 * STP * * * * * ******** *************** ******** +------+ +------+ | S7AP | | S7AP | +------+ +------+------+ +------+ | SCCP | | SCCP | SUA | | SUA | +------+ +------+------+ +------+ | MTP3 | | MTP3 | | | | +------| +------+ SCTP | | SCTP | | MTP2 | | MTP2 | | | | +------+ +------+------+ +------+ | L1 | | L1 | IP | | IP | +------+ +------+------+ +------+ | | | | +---------------+ +------------+ S7AP - SS7 Application Protocol (e.g. - RANAP/RNSAP) STP - SS7 Signaling Transfer Point The above architecture may simplify, in some cases, to carrying SS7 application protocols 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 | +------+ +------+ | | +----------------+ Loughney, et al. [Page 8] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. *********** * 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. Loughney, et al. [Page 9] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. 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 * * | ******** | * * ******** * * | * SGP1 +---------------------------------------------+ ASP1 * * * | ******** | * * ******** * * | ******** | * * ******** * * | * SGP2 +--------------------------+ +----------+ ASP2 * * * | ******** | * | | * ******** * * +----------+ * | | * . * * +----------+ * | | * . * * | AS2 | * | | * . * * | ******** | * | | * ******** * * | * SGP1 +----------------------------------+ * * ASPN * * * | ******** | * SCTP Associations | * ******** * * | ******** | * | ************** * | * SGP2 +---------------- | * | ******** | * | | ************** * +----------+ * | | * AS4 * **************** | | * ******** * | +------------------+ ASP1 * * | * ******** * | * . * | * . * | * * | * ******** * +-----------------------------+ ASPn * * * ******** * Loughney, et al. [Page 10] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 ************** Figure 2: Signaling Gateway Architecture The pair of SGs can either operate as replicated endpoints or as replicated relay points from the SS7 network point of view. Replicated endpoints : only for the first message in a transaction or connection one of the SGs is chosen, depending on the traffic mode (primary/backup or loadsharing) and overload conditions. Once selected, the same SG is used for the subsequent messages. Replicated relay points : 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 MTP to re-route to the other SG. 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 others may be inactive but available in the event of failure or unavailability of the active ASP(s). 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. Loughney, et al. [Page 11] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 * 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. 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. Loughney, et al. [Page 12] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 * Provide the initiation of an audit of remote SS7 endpoints at the SG. 1.4.6 Relay function An SCTP association exists between two SUA endpoints. For network scalability purposes, the SUA may be enhanced with a relay functionality to determine the next hop SCTP association towards the destination SUA endpoint. The determination of the next hop may be based on Global Title information (e.g. E.164 number), in analogy with SCCP GTT in SS7 networks, modelled in [ITU-T Q.714]. It may also be based on Hostname information. The relay function is invoked when : - routing is on Global Title, - routing is on Hostname. Translation/resolution of the above address information must yield either of the following : - Route on SSN : SCTP association ID towards the destination node + SSN + Network Appearance (optional) - Route on GT : SCTP association ID towards next relay node + (new) GT + SSN (optional) + Network Appearance (optional) - Routing on Hostname : SCTP association ID towards next relay node + (new) Hostname + SSN (optional) + Network Appearance (optional) - A local SUA-user (combined relay/end node) To prevent endless hopping, the hop counter is used. The originating end node (be it an SS7 or an IP node) sets the value of the hop counter to the maximum value (15). Each time the relay function is invoked within an intermediate (relay) node, the hop counter must be decremented. When the value reaches zero, and the translation result is still _Route on GT_ or _Route on Hostname_, the return or refusal procedures are invoked with reason _Hop counter violation_. 1.5 Internal Functions Provided in the SUA Layer 1.5.1 Address Translation and Mapping at the SG The SG MUST provide address translation and mapping functions to direct messages received from the SS7 network to the appropriate IP destination. In order to support message distribution, the SG maintains an address translation table, which maps the incoming SS7 messages to the appropriate AS. The relevant fields of the incoming SS7 message is compared to the existing Routing Keys. The Routing Keys Loughney, et al. [Page 13] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 reference an Application Server, which will have one or more ASPs processing traffic for the AS. The availability and status of the ASPs is handled by SUA ASP management messages. Possible SS7 address/routing information that comprise a Routing Key entry includes, for example, OPC, DPC, SIO found in the MTP3 routing label, or other specific fields such as the SCCP subsystem number, or TCAP transaction ID. Some possibilities include: Global Title (+ SSN optionally) PC (+ SSN optionally) Host Name (+ SSN optionally) IP Address(es) (+ SSN optionally) An Application Server maintains a list of ASPs that are available to process the traffic. The list is dynamic, based upon the availability of the individual ASPs in the list. SUA ASP management messages are used to convey the status of these ASPs and their availability in failover situations. Normally, one or more ASPs is active in the ASP (i.e., currently processing traffic) but in certain failure and transition cases it is possible that there may not be an active ASP available. Both load-sharing and backup scenarios are supported. If there is no Routing Key match for an incoming SS7 message, a default treatment MUST be specified. Possible solutions are to provide a default Application Server to direct all unallocated traffic to a (set of) default ASP(s), or to drop the messages and provide a notification to management. The treatment of unallocated traffic is implementation dependent. 1.5.2 Address Translation and Mapping at the ASP In order to direct messages to the SS7 network, the ASP must also perform an address translation and mapping function in order to choose the proper SG or SGP for a given message. This is accomplished by observing the Destination Point Code and other elements of the outgoing message, SS7 network status, SG and SGP availability, and network appearance configuration tables. A remote Signaling Gateway may be composed of one or more SGPs that are capable of routing SS7 traffic. As is the case with ASPs, a dynamic list of SGPs in an SG can be maintained, taking into account the availability status of the individual SGPs, configuration changes and fail-over mechanisms. There is, however, no SUA messaging to manage the status of an SGP. Whenever an SCTP association to an SGP exists, it is assumed to be available. Also, every SGP of one SG communicating with one ASP regarding one AS provides identical SS7 connectivity to this ASP. Loughney, et al. [Page 14] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 1.5.3 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): 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) Loughney, et al. [Page 15] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. 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 Loughney, et al. [Page 16] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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) 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) Loughney, et al. [Page 17] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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) 3 Connection Refused (COREF) 4 Release Request (RELRE) 5 Release Complete (RELCO) 6 Reset Confirm (RESCO) 7 Reset Request (RESRE) 8 Connection Oriented Data Transfer (CODT) 9 Connection Oriented Data Acknowledge (CODA) 10 Connection Oriented Error (COERR) 11 Inactivity Test (COIT) 12 - 127 Reserved by the IETF 128 - 255 Reserved for IETF-Defined Message Class Extensions 3.1.4 Message Length The Message Length defines the length of the message in octets, including the header. 3.1.5 Tag-Length-Value Format SUA messages consist of a Common Header followed by zero or more parameters, as defined by the message type. The Tag-Length-Value (TLV) parameters contained in a message are defined in a Tag- Length-Value format as shown below. 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 / \ \ Loughney, et al. [Page 18] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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 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. Implementation note : the use of TLV in principle allows the parameters to be placed in a random order in the message. However, some guidelines should be considered for easy processing in the following order : - parameters needed to correctly process other message parameters, preferably should precede these parameters (such as Network Appearance), mandatory parameters preferably should precede any optional parameters, - the data parameter will normally be the final one in the message. 3.2 SUA Connectionless Messages The following section describes the SUA Connectionless transfer messages and parameter contents. The general message format includes a Common Message Header together with a list of zero or more parameters as defined by the Message Type. All Message Types can have attached parameters. 3.2.1 Connectionless Data Transfer (CLDT) This message transfers data between one SUA to another. 0 1 2 3 Loughney, et al. [Page 19] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Flags Mandatory Source Address Mandatory Destination Address Mandatory Data Mandatory Implementation Note: This message covers the following SCCP messages: unitdata (UDT), extended unitdata (XUDT), long unitdata (LUDT). 3.2.2 Connectionless Data Response (CLDR) This message is used as a response message by the peer to report errors in the received CLDT message, when the return on error option is set. 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 | Loughney, et al. [Page 20] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Flags Mandatory SCCP Cause Mandatory Source Address Mandatory Destination Address Mandatory Data Optional Implementation note: This message covers the following SCCP messages: unitdata service (UDTS), extended unitdata service (XUDTS) and long unitdata service (LUDTS). 3.3 Connection Oriented Messages 3.3.1 Connection Oriented Data Transfer (CODT) This message transfers data between one SUA to another for connection oriented service. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 21] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Sequence number Mandatory *1 Destination Reference Number Mandatory Data Mandatory NOTE *1: 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 (CODA) This message is used to acknowledge receipt of data by the peer. This message is used only with protocol class 3. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0108 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Loughney, et al. [Page 22] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Network Appearance Optional 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 Connection Request (CORE) This message is used for establishing a signaling connection between two peer endpoints. This is used 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 23] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Parameters Flags Mandatory Source Reference Number Mandatory Destination Address Mandatory Source Address Optional Credit Optional Data Optional 3.3.4 Connection Acknowledge (COAK) This message is used to acknowledge a connection request between two peer endpoints. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Flags Mandatory Destination Reference Number Mandatory Source Reference Number Mandatory Credit Optional *2 Destination Address Optional *1 Data Optional Loughney, et al. [Page 24] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 NOTE *1: Destination Address parameter will be present in case that the received CORE message conveys the Source Address parameter. Note *2: Used for protocol class 3. 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. 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 = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Destination Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory SCCP 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. Loughney, et al. [Page 25] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.3.6 Release Request (RELRE) This message is used to request a signaling connection between two peer endpoints be released. All associated resources can then be released. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0003 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory SCCP Cause Mandatory Flags Optional Data Optional Implementation Note: This message covers the following SCCP message: Connection Refused (RLSD). 3.3.7 Release Complete (RELCO) This message is used to acknowledge the release of a signaling connection between two peer endpoints. All associated resources should be released. 0 1 2 3 Loughney, et al. [Page 26] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Implementation Note: This message covers the following SCCP message: Release Complete (RLC). 3.3.8 Reset Request (RESRE) 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 = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory SCCP Cause Mandatory Implementation note: This message covers the following SCCP message: reset request (RSR). Loughney, et al. [Page 27] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.3.9 Reset Confirm (RESCO) This message is used to confirm the Reset Request. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Implementation note: This message covers the following SCCP message: Reset Confirmation (RSC). 3.3.10 Connection Oriented Error (COERR) The COERR message is sent to indicate a protocol data unit error. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCCP Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Destination Reference Number Mandatory SCCP Cause Mandatory Implementation Note: This message covers the following SCCP message: Protocol Data Unit Error (ERR) Loughney, et al. [Page 28] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.3.11 Connection Oriented Inactivity Test (COIT) This message is used for auditing the signaling connection state and the consistency of connection data at both ends of the signaling connection. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0101 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Flags Mandatory Source Reference Number Mandatory Destination Reference number Mandatory Sequence number Mandatory *1 Credit Mandatory *1 NOTE *1: Information in these parameter fields reflect those values sent in the last data form 2 or data acknowledgement message. They are ignored if the protocol class indicates class 2. Implementation note: This message covers the following SCCP message: Inactivity Test (IT). 3.4 SS7 Signaling Network Management Messages 3.4.1 Destination Unavailable (DUNA) Loughney, et al. [Page 29] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 In the scope of SUA, this message is covered by the PC state indication passed between SCCP and local SCCP-user. The DUNA message is sent from the SG to all concerned ASPs (servicing SCCP-users considered local to the SG, see chapter 1.3.1.1), when an SS7 destination has become unreachable. The SUA-User at the ASP is expected to stop traffic to the affected destination through the SG initiating the DUNA. The format for DUNA Message parameters is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Affected Point Code Mandatory Info String Optional 3.4.2 Destination Available (DAVA) In the scope of SUA, this message is covered by the PC state indication passed between SCCP and local SCCP-user. The DAVA message is sent from the SG to all concerned ASPs (servicing SCCP-users considered local to the SG, see chapter 1.3.1.1) to indicate 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 | Loughney, et al. [Page 30] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Affected Point Code Mandatory Info String Optional 3.4.3 Destination State Audit (DAUD) 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 Network Appearance Optional Affected Point Code Mandatory Info String Optional 3.4.4 SS7 Network Congestion (SCON) 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 31] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 = 0x000E | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ \ Affected PC \ / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Network Appearance Optional Congestion Level Mandatory Affected PC Mandatory Info String Optional 3.4.5 Destination User Part Unavailable (DUPU) The DUPU message is used in local broadcast procedures (SUA for SCCP - SCCP user interface). In remote broadcast procedures, use SCMG message formatID SSP (peer SUA message) The format for DUPU Message parameters is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected Point Code / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0009 | Length | Loughney, et al. [Page 32] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 (SCMG) The SCMG message is sent between SUA Peers to indicate status of subsystems. Only one SCMG message type can be sent per 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 = 0x0001 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010B | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCMG Format Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMI/Subsystem | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0005 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Affected PC / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x000E | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Congestion Level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String \ \ / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Loughney, et al. [Page 33] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Network Appearance Optional SCMG Format Identifier 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 not present. 3.5 Application Server Process Maintenance Messages 3.5.1 ASP Up (UP) The ASP UP (UP) message is used to indicate to a remote SUA peer that the Adaptation layer is up and running. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ASP Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters ASP Capabilities Optional Info String Optional 3.5.2 ASP Up Ack (UP ACK) The ASP UP Ack message is used to acknowledge an ASP-Up message received from a remote SUA peer. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ASP Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | Loughney, et al. [Page 34] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters ASP Capabilities Optional Info String Optional 3.5.3 ASP Down (DN) The ASP Down (DN) message is used to indicate to a remote SUA peer that the adaptation layer is not running. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x000A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reason | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Reason Mandatory Info String Optional 3.5.4 ASP Down Ack (DOWN ACK) The ASP DOWN Ack message is used to acknowledge an ASP-Down message received from a remote SUA peer. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x000A | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reason | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Reason Mandatory Loughney, et al. [Page 35] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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: 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 = 0x0008 | 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 = 0x0008 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Heartbeat Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Heartbeat Data Optional 3.6 ASP Traffic Maintenance Messages 3.6.1 ASP Active (ACTIVE) The ASPAC message is sent by an ASP to indicate to a remote SUA peer that it is Active and ready to process signaling traffic for a particular Application Server The format for the ACTIVE message is as follows: Loughney, et al. [Page 36] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 = 0x000B | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic Mode Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Traffic Mode Type Mandatory Routing Context Optional Info String Optional 3.6.2 ASP Active Ack (ACTIVE ACK) The ASPAC Ack message is used to acknowledge an ASP-Active message received from a remote SUA peer. The format for the ACTIVE Ack message is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x000B | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic Mode Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Traffic Mode Type Mandatory Loughney, et al. [Page 37] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Routing Context Optional Info String Optional The format of the Traffic Mode Type and Routing Context parameters is the same as for the ASP-Active message. The format and description of the optional Info String parameter is the same as for the ASP-Active message. 3.6.3 ASP Inactive (INACTIVE) The INACTIVE message is sent by an ASP to indicate to a remote SUA peer that it is no longer processing 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 = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Routing Context Optional INFO String Optional 3.6.4 ASP Inactive Ack (INACTIVE ACK) The INACTIVE Ack message is used to acknowledge an ASP-Inactive message received from a remote SUA peer. The format for the INACTIVE Ack message is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | Loughney, et al. [Page 38] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / INFO String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parameters Routing Context Optional INFO String Optional The format of the Traffic Mode Type and Routing Context parameters is the same as for the ASP-Active message. The format and description of the optional Info String parameter is the same as for the ASP-Active message. 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 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 39] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 | Tag = 0x000D | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status Type/ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0004 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Info String / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The NTFY message contains the following parameters: Parameters Status Type/ID 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 Not used in SUA 0x0002 Data 0x0003 Info String 0x0004 Affected Point Code 0x0005 Routing Context 0x0006 Diagnostic Info 0x0007 Heartbeat Data 0x0008 Cause/User 0x0009 Reason 0x000A Traffic Mode Type 0x000B Not used 0x000C Status Type 0x000D Congestion Level 0x000E 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 Process over a common SCTP Association. An example is where an SG is Loughney, et al. [Page 40] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 logically partitioned to appear as an element in several different national SS7 networks. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Network Appearance implicitly defines the SS7 Point Code format used, the SS7 Network Indicator value and SCCP 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 context, the Network Appearance parameter is not required. The Network Appearance parameter value is 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 Protocol Data field. 3.8.2 Not used Parameter ID 0x02 is not used in SUA. 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 / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Data parameter field contains the SS7 SCCP-User application message, for example an INAP/TCAP message. 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. Loughney, et al. [Page 41] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 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 = 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / . . . / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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| Loughney, et al. [Page 42] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 can be used to identify a contiguous range of Affected Destination Point Codes, independent of the point code format. Identifying a contiguous range of Affected PCs may be useful when reception of an MTP3 management message or a linkset event simultaneously affects the availability status of a series of destinations at an SG. The Mask parameter is an integer representing a bit mask that can be applied to the related Affected PC field. The bit mask identifies how many bits of the Affected PC field is significant and which are effectively "wild-carded". For example, a mask of "8" indicates that the last eight bits of the PC is "wild-carded". For an ANSI 24-bit Affected PC, this is equivalent to signaling that all PCs in an ANSI Cluster are unavailable. A mask of "3" indicates that the last three bits of the PC is "wild-carded". For a 14-bit ITU Affected PC, this is equivalent to signaling that an ITU Region is unavailable. 3.8.6 Routing Context 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0006 | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Routing Context parameter contains (a list of) 4-byte unsigned integers indexing the Application Server traffic that the sending ASP is configured/registered to receive. There is one-to-one relationship between an index entry and a SG Routing Key or AS Name. Since an AS can only appear in one Network Appearance, the Network Appearance parameter is not required in the ASP Active 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. Loughney, et al. [Page 43] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 The Heartbeat Data field contents are defined by the sending node. It may include a Heartbeat Sequence Number and/or Timestamp, other implementation specific details. The receiver of a Heartbeat message does not process this field as it is only of significance to the sender. The receiver echoes the content of the Heartbeat Data in a BEAT-Ack message. 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 = 0x0008 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Heartbeat Data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The data field can be used to store information in the heartbeat message useful to the sending node (e.g. the data field can contain a time stamp, a sequence number, etc.). 3.8.9 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 = 0x0009 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | User | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 44] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 Reason The Reason parameter indicates the reason that the remote SUA adaptation layer is unavailable. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0009 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | User | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reason: 32-bit (unsigned integer) The valid values for Reason are shown in the following table. 0 Unspecified 1 User Unavailable 2 Management Blocking 3 ASP Fault 3.8.11 Traffic Mode Type The Traffic Mode Type parameter identifies the traffic mode of operation of the ASP within an AS. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 45] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 | Tag = 0x000B | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Traffic Mode Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The valid values for Type are shown in the following table. 1 Over-ride 2 Load-share 3 Over-ride (Standby) 4 Loadshare (Standby) Within a Routing Context, Over-ride and Loadshare Types cannot be mixed. The Over-ride value indicates that the ASP is operating in Over-ride mode, and the ASP wishes to take over all traffic for an Application Server (i.e., primary/back-up operation), over-riding any currently active ASP in the AS. In Load-share mode, the ASP wishes to share in the traffic distribution with any other currently active ASPs. The Standby versions of the Over-ride and Loadshare Types indicate that the ASP is declaring itself ready to accept traffic but leaves it up to the sender as to when the traffic is started. Over-ride (Standby) indicates that the traffic sender continues to use the currently active ASP until it can no longer send/receive traffic (i.e., the currently active ASP transitions to Down or Inactive). At this point the sender may immediately move the ASP to Active and commence traffic. Loadshare (Standby) is similar - the sender continues to loadshare to the current ASPs until there it is determined that there is insufficient resources in the Loadshare group. When there is insufficient ASPs, the sender may immediately move the ASP to Active. 3.8.12 Error Code 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag =0x000C | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 Appearance 0x02 Unexpected Message Class 0x03 Invalid Message Type 0x04 Unsupported Traffic Handling Mode 0x05 Unexpected Message 0x06 Protocol Error 0x07 Loughney, et al. [Page 46] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Invalid Routing Context 0x08 Invalid Stream Identifier 0x09 Parameter Field Error 0x0B Unexpected Parameter 0x0C Duplicated Parameter 0x0D 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. The "Invalid Network Appearance" error would be sent by a SG if an ASP sends a message with an invalid (unconfigured) Network Appearance 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 Routing Context" error would be sent by a SG if the routing context cannot be supported, e.g. not unique. 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 "Parameter Field Error" would be sent if a message with a parameter having a wrong length field. The "Unexpected Parameter" error would be sent if a message contains an invalid parameter. The "Duplicated Parameter" error would be sent if a message contains a parameter more than once. The Cause parameter can be one of the following values: Invalid Version 0x1 Invalid Network Appearance 0x2 Invalid Adaptation Layer Identifier 0x3 Loughney, et al. [Page 47] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Invalid Message Type 0x4 Invalid Traffic Handling Mode 0x5 Unexpected Message Type 0x6 Protocol Error 0x7 Invalid Routing Context 0x8 Unsupported Message Type 0x9 3.8.13 Status Type 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The valid values for Status Type (16 bit unsigned integer) are: 1 Application Server state change (AS_State_Change) 2 Other The Status ID parameter contains more detailed information for the notification, based on the value of the Status Type. If the Status Type is AS_STATE_CHANGE, then the Status ID (16 bit unsigned integer) values are: 1 reserved 2 Application Server Inactive (AS-Inactive) 3 Application Server Active (AS-Active) 4 Application Server Pending (AS-Pending) These notifications are sent from an SG to an ASP upon a change in status of a particular Application Server. The value reflects the new state of the Application Server. If the Status Type is Other, then the following Status Information values are defined: 1 Insufficient ASP resources active in AS 2 Alternate ASP Active These notifications are not based on the SG reporting the state change of an ASP or AS. In the Insufficient ASP Resources case, the SG is indicating to an "Inactive" ASP(s) in the AS that another ASP is required in order to handle the load of the AS (Load-sharing mode). For the Alternate ASP Active case, an ASP is informed when Loughney, et al. [Page 48] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 an alternate ASP transitions to the ASP-Active state in Over-ride mode. 3.8.14 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 = 0x000E | 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. 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. 3.9 SUA-Specific parameters These TLV parameters are specific to the SUA protocol. Parameter Name Parameter ID ============== ============ Flags 0x0101 Source Address 0x0102 Destination Address 0x0103 Source Reference Number 0x0104 Destination Reference Number 0x0105 SCCP Cause 0x0106 Sequence Number 0x0107 Loughney, et al. [Page 49] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Receive Sequence Number 0x0108 ASP Capabilities 0x0109 Credit 0x010A SCMG Format Identifier 0x010B SMI / Subsystem 0x010C Destination/Souce Address Sub Parameters ======================================== Global Title 0x0801 Point Code 0x0802 Subsystem Number 0x0803 IPv4 Address 0x0804 Hostname 0x0805 IPv6 Addresses 0x0806 3.9.1 Flags The Flags parameter is a conglomerate of following parameters, described in ITU-T Recommendation Q.713 : 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 (= 4) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Importance | Hop Counter | Protocol Cl. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Protocol class (3.6/Q.713) Bits 1-2 indicate the 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) Bit 8 indicates the use of the return on error procedure Value Description 0x0 No special options 0x1 Return message on error Bits 3-7 are spare and should be coded zero. - Hop Counter (3.18/Q.713) The value of the hop counter is decremented with each global title translation, and should be in the range 15 to 1. - Importance (3.19/Q.713) Loughney, et al. [Page 50] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Bits 1-3 are coded to indicate the importance of the messages. The values are between 0 and 7, where the value of 0 indicates the least important and 7 indicates the most important. Bits 4-8 are spare bits. 3.9.2 Source Address 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0102 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Routing Indicator | Address Indicator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Address parameter(s) / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Source Address field may contain the SCCP Calling Party Address. See chapters 3.4 and 3.5 of ITU-T Recommendation Q.713. The following combinations of address parameters are valid : - Global Title (e.g. E.164 number) + optional PC and/or SSN, SSN may be zero, when routing is done on Global Title - PC and SSN (non-zero) + optional Global Title, when routing is done on PC + SSN - Hostname + optional SSN, when routing is done by Hostname - IPv4 or IPv6 address + optional SSN, when routing is done by IP address 3.9.2.1 Routing Indicator The following values are valid for the routing indicator : Reserved 0 Route on Global Title 1 2 Route on SSN + PC 2 Route on SSN + IP Address 3 Route on Hostname 43 The routing indicator determines which address parameters need to be present in the address parameters field. 3.9.2.2 Address Indicator This parameter is needed for interworking with SS7 networks. The address indicator specifies what address parameters are actually received in the SCCP address from the SS7 network, or are to be Loughney, et al. [Page 51] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 populated in the SCCP address when the message is sent into the SS7 network. The value of the routing indicator needs to be taken into account. The address indicator is coded as follows: Bit 1 is used to indicate inclusion of the SSN 0 do not include SSN when optional (routing indicator /= 2) 1 include SSN Bit 2 is used to indicate inclusion of the PC 0 do not include PC, regardless of the routing indicator value 1 include PC Bit 3 is used to indicate inclusion of the Global Title 0 do not include GT when optional (routing indicator /= 1) 1 include GT In the next chapters, the layout of the address parameters is given. The following tags are used to identify the address parameters: 0x00 Reserved 0x01 Global Title 0x02 Point Code 0x03 Subsystem Number 0x04 IPv4 0x05 Hostname 0x06 IPv6 3.9.2.3 Global Title 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0801 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Trans. type |E| Num. Plan | Nature of Add | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Global Title Digits | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Translation type: Loughney, et al. [Page 52] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 0 Unknown 1 - 63 international services 64 - 127 spare 128 - 254 national network specific 255 reserved 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. 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: Loughney, et al. [Page 53] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. The actual Global Title format to be used for interworking with the SS7 network is defined by the network appearance, or is implicitly understood if the SG only operates in one SS7 network partition. The formats are defined in chapter 3.4.2.3 of Q.713. The following conversions of the Translation Type, Numbering Plan Odd/Even indicator and Nature of Address elements apply : 1) SS7 network uses GTI = 0001 Odd/Even indicator and Nature of Address are taken over. It is implicitly assumed that Translation Type = Unknown and Numbering Plan = E.164 (value 1). 2) SS7 network uses GTI = 0010 This is most commonly used in North American networks. The Translation Type implicitly determines Nature of Address and Numbering Plan. This data can be configured in the SG. 3) SS7 network uses GTI = 0011 Odd/Even indicator, Numbering Plan and Translation Type are taken over. It is implicitly assumed that the Nature of Address = Unknown. 4) SS7 network uses GTI = 0100 This format is used in international networks and most commonly in networks outside North America. All information is present in the SS7 SCCP Global Title as well. Loughney, et al. [Page 54] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.9.2.4 Point Code 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0802 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Point Code | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ See chapter 3.2.5 Affected Point Code for the layout of the Point Code field. 3.9.2.5 Subsystem Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0803 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSN value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The internationally standardized SSN values are described in chapter 3.4.2.2 of Q.713. 3.9.2.6 IP Addresses The IP address formats can use different tags. It should be noted that if the source address is in a certain IP version, the destination address should also be in the same IP version. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x10040x0804/0x1006 0x0806 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 or IPv6 Address | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 55] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.9.2.7 Hostname 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0805 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Host Name | / / | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ If the type of address is Host Name, then the labels in the host name have to be reversed to obtain an 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: Loughney, et al. [Page 56] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ 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 | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+20| E | L | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+22| 3 | W | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ x+24| W | W | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | 00 | | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ 3.9.3 Destination Address 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0103 | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Routing Indicator | Address Indicator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / address parameter(s) / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The format of this parameter is identical to the Source Address parameter. Loughney, et al. [Page 57] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.9.4 Source Reference Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0104 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The source reference number is a 4 octet long integer. This is allocated by the source SUA instance. 3.9.5 Destination Reference Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0105 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Reference Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The destination reference number is a 4 octet long integer. This is allocated by the destination SUA instance. 3.9.6 SCCP Cause 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0106 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Cause Type | Cause Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This parameter bundles the SCCP parameters Release cause, Return cause, Reset cause, Error cause and Refusal cause. Cause Type can have the following values: Return Cause 0x1 Refusal Cause 0x2 Release Cause 0x3 Reset Cause 0x4 Error Cause 0x5 Cause Value contains the specific cause value. Below gives examples for ITU SCCP values. ANSI references can be found in ANSI T1.112.3 Cause value in Correspondence with Reference Loughney, et al. [Page 58] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 3.9.7 Sequence Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0107 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Rec Seq Num |M| Sent Seq Num | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This parameter is used to indicate whether _more_ data will follow in subsequent CODT messages, and to number each CODT message sequentially for the purpose of flow control. It contains the more indicator, and the received as well as the sent sequence number, P(R) and P(S) in Q.713, chapters 3.7 and 3.9. As such it can also be used to acknowledge the receipt of data transfers from the peer in case of protocol class 3. Sent Sequence Number is one octet and is coded as follows: Bits 2-8 are used to indicate the Send Sequence Number P(S). Bit 1 (LSB) of octet 1 is spare. Received Sequence Number is one octet, and is coded as follows: Bits 2-8 are used to indicate the Received Sequence Number P(R). Bit 1 (LSB) is used for the more data indication, as follows: 0 no more data 1 more data Loughney, et al. [Page 59] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 3.9.8 Receive Sequence Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0108 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare | Rec Seq Num | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This parameter is used exclusively for protocol class 3 in the data acknowledgment message to indicate the lower edge of the receiving window. See Q.713, chapter 3.8. 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. 3.9.9 ASP Capabilities This parameter is used so that the ASP can report it's capabilities regarding SUA for supporting different protocol classes and interworking scenarios. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x0109 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | spare |0 0 0 0|a|b|c|d| Interworking | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The length is two octets. Flags a - Protocol Class 3 b - Protocol Class 2 c - Protocol Class 1 d - Protocol Class 0 It is mandatory to support at least Protocol Class 0. Interworking Values 0x0 indicates no interworking with SS7 Networks. 0x1 indicates IP Signaling Endpoint (ASP). Loughney, et al. [Page 60] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 = 0x010A | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The length of the credit field is is one octet. See ITU-T Q.713 chapter 3.10. 3.9.11 SCMG Format Identifier 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag = 0x010B | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SCMG Format Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The SCMG Format Identifier 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 (ANSI SCCP Specific) 254 SBR (ANSI SCCP Specific) 255 SRT (ANSI SCCP Specific) 3.9.12 SMI / Subsystem 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SMI | Spare | SSN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Subsystem Number (SSN) is one octet. Loughney, et al. [Page 61] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 Subsystem Multiplicity Indicator (SMI) can have the following values: 0x00 Reserved 0x01 Replicated 0x02 Solitary 0x03 Unknown 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 SUA procedures in response to these events. 4.1 SCCP _ SUA Interworking at the SG On the SG, the SCCP routing or interworking function determines that the message must be sent to an AS via the SUA stack, based on information in the incoming message. The SUA outgoing mapping function identifies the appropriate Application Server (AS) and selects an active ASP from the list of ASPs servicing this AS. 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 then constructed and sent to the appropriate endpoint, via the correct SCTP association and stream. 4.1.1 Connection Oriented Procedures On receipt of a CR message from the SS7 network, a first connection section is established between the SG and SS7 originating node. A second connection section is to be setup between the SG and the appropriate ASP, determined by the SUA outgoing mapping function. Local resources and source local reference numbers are allocated to keep/retrieve the required address information and the connection state in order to format and route subsequent messages for the connection based on reference numbers only. The existing SCCP procedures can be deployed by SUA to perform this coupling of connection sections. The same applies for a CORE message received from the IP network, destined for an SS7 node. After allocating the necessary resources, the SUA incoming mapping function formats the appropriate SCCP message and passes it on to SCCP routing for further processing (sending into the SS7 network). 4.1.2 Connectionless Procedures Loughney, et al. [Page 62] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 The existing SCCP routing functions may be enhanced to support interworking with the SUA layer. The function of SUA can be limited to outgoing mapping (formatting of the CLDT or CLDR message) and selection of the correct SCTP association (ASP) and stream. For the direction ASP to SG, the SUA incoming mapping formats the appropriate SCCP message (UDT(S), XUDT(S) or LUDT(S)) and passes it on to SCCP routing for further processing. The SG MUST take care of any segmentation / reassembly at the border of the SS7 and IP networks. The IPSP may not have any knowledge about the requirements of the SS7 network to which it is sending to. 4.1.3 SS7 Signaling Network Management Procedures When an SCCP Subsystem Management (SCMG) message is received from the SS7 network, it has to be determined whether there are concerned Application Servers, interested in subsystem status changes. The normal SCCP management procedures for local and remote broadcast can be deployed, but the SUA outgoing mapping function is called upon to format and transfer these SCMG messages to the appropriate list of concerned ASPs. When MTP-3 Management indications are received (MTP-PAUSE, MTP- RESUME, MTP-STATUS), SCCP Subsystem Management determines whether there are concerned local SCCP-users. When these local SCCP-users are in fact Application Servers, serviced by ASPs, SUA outgoing mapping is called upon to format the appropriate SUA message (DUNA, DAVA or SCON) and forward it on the correct SCTP associations (ASPs) on the appropriate stream (streamID _0_ for management messages). When the DAUD message is received at the SG from an ASP, the SG checks the status of the specified SS7 destination and returns DAVA, DUNA or SCON depending on the result of the check. No SS7 procedures are triggered. SCCP Subsystem Management procedures may also be triggered in case of AS state changes, see chapter 4.4.1.2. 4.2 Primitives received from the local SUA-user These support the SUA transport of SCCP-User/SCCP boundary primitives. The same services as supported by SCCP (connectionless and connection-oriented) are to be provided by SUA. The SCCP-users at the SG should be able to use the same primitive interface to SCCP/SUA without any changes. The SCCP-SUA interworking function takes care of selecting the appropriate stack. The SUA needs to setup and maintain the appropriate SCTP association to the selected endpoint. SUA also manages the usage of SCTP streams. Loughney, et al. [Page 63] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 The address information passed by the SUA-user at an ASP must contain either : - a valid SS7 address to reach a destination in the SS7 network via the appropriate SCTP association to a SG, - a valid IP address/hostname to reach another ASP in the IP network via the appropriate SCTP association. 4.3 Layer Management Procedures On receiving primitives from the local Layer Management, the SUA layer will take the requested action and provide a response to Layer Management. An M-SCTP-ESTABLISH request from Layer Management will initiate the establishment of an SCTP association. An M-SCTP-ESTABLISH confirm will be sent to Layer Management when the initiated association set- up is complete. An M-SCTP-ESTABLISH indication is sent upon successful completion of an incoming SCTP association set-up from a peer SUA node. An M-SCTP-RELEASE request from Layer Management initiates the tear- down of an SCTP association. An M-SCTP-RELEASE confirm is sent to Layer Management when the association tear-down is complete. An M- SCCP-RELEASE indication is sent to Layer Management upon successful tear-down of an SCTP association initiated by a peer SUA. An M-SCTP-STATUS request supports a Layer Management query of the local status of a particular SCTP association. The SUA responds with the association status in an M-SCTP-STATUS confirm. No peer SUA protocol is invoked. An M-ASP-STATUS request supports a Layer Management query of the status of a particular local or remote ASP. The SUA responds with an M-ASP-STATUS confirm. No peer SUA protocol is invoked. An M-AS-STATUS request supports a Layer Management query of the status of a particular AS. The SUA responds with an M-AS-STATUS confirm. No peer SUA protocol is invoked. M-ASP-UP, -DOWN, -ACTIVE and _INACTIVE request primitives allow Layer Management at an IPSP to force state changes. Upon successful completion, a corresponding confirm primitive is issued by SUA to the Layer Management. If the invocation is unsuccessful, an Error indication is provided. Layer Management is informed by SUA Management about AS/ASP state changes with the corresponding indications. It is also informed of received NTFY or ERR messages, see chapter 4.4.3. Loughney, et al. [Page 64] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 4.4 SUA Management Procedures This functionality comprises the handling of AS/ASP state and traffic management messages, SUA peer management messages, SCTP notifications and the interface with local Layer Management. These procedures support the SUA management of SCTP Associations and ASP paths between SGs and ASPs. 4.4.1 AS and ASP State and Traffic Management The SUA layer on each IPSP (e.g. SG) needs to maintain the state of each connected IPSP (e.g. ASP), as a way to manage the traffic to these IPSPs and the (logical) ASs they service. In particular at a SG, the state of each connected ASP is needed as input to the SGs routing 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: - ASP Management messages (ASP-Up, ASP-Down, ASP-Active, ASP- Inactive) - SCTP Communication Down Notification (SCTP CDI) The state of the ASP within each AS is important in particular for the routing function at the SG, in order to direct traffic for a specific routing key (AS) to the appropriate ASP. At an ASP, if it is connected to a set of redundant SGs, this set can also be seen as an AS handling all traffic destined for the SS7 network. 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 not possible. The ASP can only handle management messages. ASP-ACTIVE: The Application Server Process is available and application traffic is possible. Whether traffic will be directed to this ASP depends on the Traffic Mode Type (over-ride, loadshare with or without Standby option). Loughney, et al. [Page 65] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-------------+ | | +----------------------| ASP-ACTIVE | | | | | +-------------+ | ^ | | ASP | | ASP | Active | | Inactive | | v | +-------------+ | | | | | ASP-UP |-------------+ | +-------------+ | | ^ | | ASP Down | ASP | | ASP Down / | ASP SCTP CDI | Up | | SCTP CDI | Down/ | | v | SCTP | +-------------+ | CDI | | | | +--------------------->| ASP-DOWN |<------------+ | | +-------------+ Figure 4: ASP State Transition Diagram SCTP CDI: The local SCTP layer's SHUTDOWN COMPLETE notification or COMMUNICATION LOST notification. The shutdown of an SCTP association may have been requested by local Layer Management, see chapter 4.3. Local Layer Management 4.4.1.2 AS States The AS is configured in the IPSP as a logical entity to handle traffic for a specific (unique) routing key. The state of the AS is maintained in the SUA layer, and can change due to following events: - ASP state changes : when the first ASP within an AS goes UP or ACTIVE, or when the last ASP within an AS goes DOWN or INACTIVE - Recovery Timer expiry 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 possible (i.e. one or more related ASPs are in the ASP-UP state, but none in the ASP-ACTIVE state). Loughney, et al. [Page 66] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 AS-ACTIVE: The Application Server is available and application traffic is possible. This state implies that at least 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 The SG maintains the availability of the ASs, and will need to issue the correct SCCP management message (where applicable) to the SS7 node(s). Loughney, et al. [Page 67] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 When an AS transitions to the UP or DOWN state, and it is the only (or last) one handling traffic for a certain SSN, an SSP message must be broadcast to the concerned remote SCCP-users in the SS7 network. When an AS transitions to the ACTIVE state, and it is the first one handling traffic for a certain SSN, an SSA message must be broadcast to the concerned remote SCCP-users in the SS7 network. 4.4.2 AS/ASP Management procedures Once an SCTP association is established between two IPSPs, one (or both) side(s) might issue an ASP-UP message. 4.4.2.1 ASP-Up An ASP sends an ASP-UP to each communication partner. When the ASP- UP message is received, the receiving IPSP can react in three different ways: - Mark the remote ASP Inactive and reply with an ASP-UP Ack message in acknowledgement to every received ASP-UP, even if the ASP is already marked as Inactive. - If for any local reason (e.g. management lock-out) the IPSP cannot respond with an ASP-UP Ack, it responds with an ASP-DOWN Ack message with Reason "Management Blocking". - If an unknown version is received with the ASP-UP message, the receiving end must respond with an Error message with Error Code _Invalid Version_. The version field in the common header will indicate to the sender which version(s) 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 as well to fallback upon in a subsequent ASP-UP message. If the ASP does not receive any of the above reactions, the ASP may resend ASP-Up messages until it receives an response. The ASP must wait for the ASP-UP Ack message before sending any other messages. If the remote peer receives any other SUA messages from an ASP, before an ASP-UP is received and acknowledged, the message should be discarded. 4.4.2.2 ASP-Down The IPSP will mark an ASP as down if one of the following events occur: - an ASP Down (ASP-DOWN) message is received from the ASP, - the ASP is locked by local Layer Management. The IPSP 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. Loughney, et al. [Page 68] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 The IPSP will send an ASP-DOWN message whenever it wants to take down a ASP. Since it is possible for ASP-DOWN and ASP-DOWN Ack messages to be lost (for example, during a node failover), the IPSP can send ASP-DOWN messages repeatedly until the path comes down (i.e. until it receives a ASP-DOWN message from the remote peer or the SCTP association goes down). 4.4.2.3 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 message is received, the remote peer responds with an ASP-ACTIVE Ack. The ASP cannot send any other messages until after the ASP-ACTIVE Ack is received. If the ASP-ACTIVE Ack is not received within a certain time, the ASP may resend the ASP-ACTIVE message. The ASP-ACTIVE message optionally contains a list of one or more Routing Contexts, indicating 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 Traffic Mode Type parameter in the ASP-ACTIVE message indicates the traffic handling mode used in a particular Application Server, either Over-ride, Over-ride (Standby), Load-share or Load-share (Standby). If the remote peer determines that the mode indicated in an ASP-ACTIVE 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 ASP-ACTIVE message at a remote peer causes the all traffic for the AS to be sent to the ASP which sent the ASP-ACTIVE. 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 ASP in the AS, after stopping all traffic to that ASP. All existing connections/transactions with the previously active ASP should be terminated however. 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 the "Inactive or "Down" state. At this point the ASP that sent the Over-Ride (Standby) ASP-ACTIVE message takes over the traffic. No Notify messages are needed. In the Load-share mode, reception of an ASP-ACTIVE message causes the redistribution of traffic to the ASP sending the ASP-ACTIVE, 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 for Loughney, et al. [Page 69] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 to service the AS. When needed, the ASP which sent the Loadshare (Standby) ASP-ACTIVE message is taken up in the loadsharing scheme and traffic is started. No Notify messages are needed to be sent. A node that receives an ASP-ACTIVE with an incorrect Traffic Mode Type for a particular Routing Context will respond with an Error Message with Error Cause _Invalid Traffic Handling Mode_. A node that receives an unknown Routing Context value responds with an Error message with Error Cause _Invalid Routing Context_. 4.4.2.4 ASP-Inactive When an ASP wishes to withdraw from handling traffic, it sends an ASP-INACTIVE to the applicable remote IPSPs, specifying the AS (Routing Context) from which it is withdrawing. If the ASP is withdrawing from more than one AS, then the ASP issues either multiple ASP-INACTIVE messages, if multiple SCTP associations exist to the remote ASPs; or a single ASP-INACTIVE message containing multiple Routing Contexts. There are two ASP-INACTIVE modes, Over-ride and load-share. If the remote peer determines that the Traffic Mode Type parameter in the ASP-INACTIVE is inconsistent with the mode being used by the Application Server, an error is reported to the local layer management, indicating _Invalid Traffic Handling Mode_. However, the ASP-INACTIVE is still handled. In the Over-ride mode, the ASP which sent the ASP-INACTIVE is marked as Inactive. No further traffic is sent from and to the ASP marked Inactive. In the Load-sharing mode, the IPSP 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 are 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 must not be sent. An ASP-INACTIVE 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 Loughney, et al. [Page 70] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 ASP-ACTIVE 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 SUA peer management messages 4.4.3.1 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 Type/ID. In the case where a NTFY (AS-Pending) message is sent by an SG that now has no active ASPs 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. 4.4.3.2 Error The ERR message is used to signal invalid protocol behaviour. 4.4.4 Heartbeat procedure 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 Loughney, et al. [Page 71] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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)-+ 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--------+ <-----------------SCMG-----------------+ Loughney, et al. [Page 72] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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--------+ <-----------------SCMG-----------------+ +-----------------DAUD-----------------> +--------SST--------> 5.1.2.2 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. 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) Loughney, et al. [Page 73] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 +-------------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. Each node is configured (via MIB, for example) 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 -| Loughney, et al. [Page 74] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 |------- 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 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------------> Loughney, et al. [Page 75] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 <----------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. 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. Loughney, et al. [Page 76] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. 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 | |_____| |____| / \ / \ / \ / \ / \ / \ / \ / \ Loughney, et al. [Page 77] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 ______ / \ / \ ______ | | / \ / \| | | 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 ______ _____ | | | | | 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. Loughney, et al. [Page 78] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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. 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. Loughney, et al. [Page 79] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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". It will be renamed to "SUA." This Port Number is the port which the SG listen to when receiving SCTP datagrams. 8.3 Protocol Extensions This protocol may also be extended through IANA in three ways: -- through definition of additional message classes, -- through definition of additional message types, 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. 8.3.1 IETF Defined Message Classes The documentation for a new message class MUST include the following information: (a) A long and short name for the message class; (b) A detailed description of the purpose of the message class. 8.3.2 IETF Defined Message Types Documentation of the message type MUST contain the following information: (a) A long and short name for the new message type; (b) A detailed description of the structure of the message. (c) A detailed definition and description of intended use of each field within the message. Loughney, et al. [Page 80] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 (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. 8.3.4 IETF-defined TLV Parameter Extension Documentation of the message parameter MUST contain the following information: (a) Name of the parameter type. (b) Detailed description of the structure of the parameter field. This structure MUST conform to the general type-length-value format described earlier in the document. (c) Detailed definition of each component of the parameter value. (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. 9 Timer Values Ta 2 seconds Tr 2 seconds T(ack) 2 seconds T(ias) Inactivity Send timer 7 minutes T(iar) Inactivity Receive timer 15 minutes 10 Acknowledgements The authors would like to thank Brian Bidulock, Martin Booyens, Marja-Liisa Hamalainen, Sherry Karl, Markus Maanoja, Chirayu Patel, Michael Purcell, Michael Tuexen, Al Varney and Ben Wilson 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 Loughney, et al. [Page 81] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 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 Loughney, et al. [Page 82] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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) [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 , Decemenber 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. Loughney, et al. [Page 83] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 [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 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 - - COIT IT Integrity Test - - X X - - Loughney, et al. [Page 84] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 COERR ERR Protocol Data Unit Error - - X X - - General Protocol Messages 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 ERR n/a n/a - - - - - X - = Message not applicable for this protocol class. X = Message applicable for this protocol class. n/a = not applicable 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 Loughney, et al. [Page 85] Internet Draft SS7 SCCP-User Adaptation Layer February 1, 2000 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 86]