INTERNET-DRAFT J. Loughney Internet Engineering Task Force Nokia G. Sidebottom, Guy Mousseau Issued: 2 July 2000 Nortel Networks Expires: 2 January 2001 S. Lorusso Unisphere Solutions 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 2 January 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 an IP Signaling Endpoint to IP Signaling Endpoint. Protocol elements are added allow seamless operation peers in the SS7 and IP domains. Internet Draft SS7 SCCP-User Adaptation Layer July 2, 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 .............................9 1.5 Internal Functions Provided in the SUA Layer ..................10 1.6 Definition of SUA Boundaries ..................................11 2 Protocol Elements .................................................11 2.1 Common Message Header .........................................11 2.2 SUA Connectionless Messages ...................................13 2.3 Connection Oriented Messages ..................................15 2.4 SS7 Signaling Network Management Messages .....................19 2.5 Application Server Process Maintenance Messages ...............23 2.6 Management Messages ...........................................27 2.7 Vendor Specific Message .......................................29 2.8 Fixed Length Parameters .......................................30 2.9 Variable Length Paramters .....................................34 3 Procedures ........................................................36 3.1 Peer Message Procedures .......................................36 3.2 Signaling Gateway Related Procedures ..........................36 3.3 Layer Management Procedures ...................................36 3.4 SCTP Management Procedures ....................................36 4 Examples of SUA Procedures ........................................41 4.1 Establishment of Association ..................................41 4.2 ASP fail-over Procedures ......................................41 4.3 SUA/SCCP-User Boundary Examples ...............................42 5 Security ..........................................................42 5.1 Introduction ..................................................42 5.2 Threats .......................................................42 5.3 Protecting Confidentiality ....................................43 6 IANA Considerations ...............................................43 6.1 SCTP Protocol ID ..............................................43 6.2 Port Number ...................................................43 7 Timer Values ......................................................43 8 Acknowledgements ..................................................43 9 Authors' Addresses ................................................43 10 References .......................................................44 Appendix A: Message mapping between SCCP and SUA. ...................45 Copyright Statement .................................................45 Loughney, et al. [Page 2] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 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. In these networks, they may be some need for interworking between the SS7 and IP domains. IP provides an effective way to transport user data and for operators to expand their networks and build new services. This document details the delivery of SCCP-user messages (MAP & CAP over TCAP, RANAP, etc.) and new third generation network protocol messages over IP between two signaling endpoints. Consideration is given for the transport from an SS7 Signaling Gateway (SG) to an IP signaling node (such as an IP-resident Database) as described in the Framework Architecture for Signaling Transport [2719]. This protocol can also support transport of SCCP-user messages between two endpoints wholly contained within an IP network. The delivery mechanism SHOULD meet the following criteria: * Support for transfer of SS7 SCCP-User Part messages (e.g., TCAP, RANAP, etc.) * Support for SCCP connectionless service. * Support for SCCP connection oriented service. * Support for the seamless operation of SCCP-User protocol peers * Support for the management of SCTP transport associations between a SG and one or more IP-based signaling nodes). * Support for distributed IP-based signaling nodes. * Support for the asynchronous reporting of status changes to management The protocol is modular in design, allowing different implementations to be made, based upon the environment that needs to be supported. Depending upon the upper layer protocol supported, the SUA will need to support SCCP connectionless service, SCCP connect-orient service or both services. 1.2 Terminology Signaling Gateway (SG) - Network element that terminates SCN signaling and transports SCCP-User signaling over IP to an IP signaling endpoint. A Signaling Gateway could be modeled as one or more Application Servers, which is located at the border of the SS7 and IP networks. Application Server (AS) - A logical entity serving a specific Routing Key. An example of an Application Server is a virtual switch element handling all call processing for a unique set of SCCP-users. The AS contains a set of one or more unique Application Server Processes, of which one or more is normally actively processing traffic. Application Server Process (ASP) - An Application Server Process serves as an active or 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. Loughney, et al. [Page 3] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 DPC and SSN to which all traffic would be directed to a particular Application Server. Routing Keys are mutually exclusive in the sense that a received SS7 signaling message cannot be directed to more than one Routing Key. A Routing Key cannot extend across more than a single SS7 DPC, in order to more easily support SS7 Management procedures. It is not necessary for the parameter ranges within a particular Routing Key to be contiguous. Routing Context - An Application Server Process may be configured to process traffic within more than one Application Server. In this case, the Routing Context parameter is exchanged between two ASPs, identifying the relevant Application Server. From the perspective of an ASP, the Routing Context uniquely identifies the range of traffic associated with a particular Application Server, which the ASP is configured to receive. There is a 1:1 relationship between a Routing Context value and a Routing Key within an AS. Therefore the Routing Context can be viewed as an index into an AS Table containing the AS Routing Keys. Fail-over - The capability to re-route signaling traffic as required to an alternate Application Server Process, or group of ASPs, within an Application Server in the event of failure or unavailability of a currently used Application Server Process. Fail-back may apply upon the return to service of a previously unavailable Application Server Process. Signaling Point Management Cluster (SPMC) - A complete set of Application Servers represented to the SS7 network under the same SS7 Point Code. SPMCs are used to sum the availability / congestion / User_Part status of an SS7 destination point code that is distributed in the IP domain, for the purpose of supporting management procedures at an SG. Network Appearance - The Network Appearance identifies an SS7 network context for the purposes of logically separating the signaling traffic between the SG and the Application Server Processes over a common SCTP Association. An example is where an SG is logically partitioned to appear as an element in four separate national SS7 networks. A Network Appearance implicitly defines the SS7 Point Code(s), Network Indicator and MTP3 protocol type/variant/version used within a specific SS7 network partition. An physical SS7 route-set or link-set at an SG can appear in only one network appearance. The Network Appearance is not globally significant and requires coordination only between the SG and the ASP. Network Byte Order - Most significant byte first, a.k.a. Big Endian. Layer Management - Layer Management is a nodal function in an SG or ASP that handles the inputs and outputs between the SUA layer and a local management entity. Loughney, et al. [Page 4] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 architecture can be modeled as a peer-to-peer architecture. 1.3.1 Protocol Architecture for TCAP Transport In this architecture, the SCCP and SUA layers interface in the SG. There needs to be interworking between the SCCP and SUA layers to provide for the seamless transfer of the user messages as well as the management messages. The SUA handles the SS7 address to IP address mapping. ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * * STP * * * * * ******** *************** ******** +------+ +------+ | TCAP | | TCAP | +------+ +------+------+ +------+ | SCCP | | SCCP | SUA | | SUA | +------+ +------+------+ +------+ | MTP3 | | MTP3 | | | | +------| +------+ SCTP | | SCTP | | MTP2 | | MTP2 | | | | +------+ +------+------+ +------+ | L1 | | L1 | IP | | IP | +------+ +------+------+ +------+ | | | | +---------------+ +------------+ TCAP - Transaction Capability Application Protocol STP - SS7 Signaling Transfer Point Loughney, et al. [Page 5] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 1.3.2 Protocol Architecture for RANAP Transport In this architecture, the SS7 application protocol is invoked at the SG. For messages destined for an ASP, the SUA handles address translation, for example by way of Global Title Translation or via mapping table, resolving the destination specified by SS7 Application to a SCTP association / IP address. ******** SS7 *************** IP ******** * SEP *---------* *--------* * * or * * SG * * ASP * * STP * * * * * ******** *************** ******** +------+ +-------------+ +------+ | S7AP | | S7AP | | S7AP | +------+ +------+------+ +------+ | SCCP | | SCCP | SUA | | SUA | +------+ +------+------+ +------+ | MTP3 | | MTP3 | | | | +------| +------+ SCTP | | SCTP | | MTP2 | | MTP2 | | | | +------+ +------+------+ +------+ | L1 | | L1 | IP | | IP | +------+ +------+------+ +------+ | | | | +---------------+ +------------+ S7AP - SS7 Application Protocol (e.g. - RANAP/RNSAP) STP - SS7 Signaling Transfer Point This architecture may simplify, in some cases, to carrying an SS7 application protocol between two IP based endpoints. In this scenario, full SG functionality may not be needed. This architecture is considered in the next section. 1.3.3 All IP Architecture ******** IP ******** * *--------* * * AS * * AS * * * * * ******** ******** +------+ +------+ | AP | | AP | +------+ +------+ | SUA | | SUA | +------+ +------+ | SCTP | | SCTP | +------+ +------+ | IP | | IP | +------+ +------+ | | +----------------+ AP - Application Protocol (e.g. - RANAP/RNSAP) Loughney, et al. [Page 6] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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. 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. In this example, the Application Servers are shown residing within one logical box, with ASPs located inside. In fact, an AS could be distributed among several hosts. In such a scenario, the host should share state as protection in the case of a failure. Additionally, in a distributed system, one ASP could be registered to more than one AS. This draft should not restrict such systems - though such a case in not specified. *********** * AS1 * * +-----+ * SCTP Associations * |ASP1 +-------------------+ * +-----+ * | *********** * * | * AS3 * * +-----+ * | * +-----+ * * |ASP2 +-----------------------------------------+ASP1 | * * +-----+ * | * +-----+ * * * | * * * +-----+ * | * +-----+ * * |ASP3 | * +--------------------------+ASP2 | * * +-----+ * | | * +-----+ * *********** | | *********** | | *********** | | *********** * AS2 * | | * AS4 * * +-----+ * | | * +-----+ * * |ASP1 +--------------+ +---------------------+ASP1 | * * +-----+ * * +-----+ * * * * * * +-----+ * * +-----+ * * |ASP2 +-----------------------------------------+ASP1 | * * +-----+ * * +-----+ * * * *********** * +-----+ * * |ASP3 | * * +-----+ * * * *********** Figure 1: Generalized Architecture Loughney, et al. [Page 7] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 * * | ******** | * * ******** * * | * ASP1 +---------------------------------------------+ ASP1 * * * | ******** | * * ******** * * | ******** | * * ******** * * | * ASP2 +--------------------------+ +----------+ ASP2 * * * | ******** | * | | * ******** * * +----------+ * | | * . * * +----------+ * | | * . * * | AS2 | * | | * . * * | ******** | * | | * ******** * * | * ASP1 +----------------------------------+ * * ASPN * * * | ******** | * SCTP Associations | * ******** * * | ******** | * | ************** * | * ASP2 +---------------- | * | ******** | * | | ************** * +----------+ * | | * AS4 * **************** | | * ******** * | +------------------+ ASP1 * * | * ******** * | * . * | * . * | * * | * ******** * +-----------------------------+ ASPn * * * ******** * ************** Figure 2: Signaling Gateway Architecture 1.3.6 ASP Fail-over Model and Terminology The SUA protocol supports ASP fail-over functions in order to support a high availability of transaction processing capability. Loughney, et al. [Page 8] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 while any others are inactive but available in the event of failure or unavailability of the active ASP(s). The fail-over model supports an "n+k" redundancy model, where "n" ASPs is the minimum number of redundant ASPs required to handle traffic and "k" ASPs are available to take over for a failed or unavailable ASP. Note that "1+1" active/standby redundancy is a subset of this model. A simplex "1+0" model is also supported as a subset, with no ASP redundancy. To avoid a single point of failure, it is recommended that a minimum of two ASPs be resident in the list, resident in separate physical hosts and therefore available over different SCTP Associations. 1.4 Services Provided by the SUA Layer 1.4.1 Support for the transport of SCCP-User Messages The SUA needs to support the transfer of SCCP-user messages. The SUA layer at the SG needs to seamlessly transport the user messages. 1.4.2 SCCP Protocol Class Support Depending upon the SCCP-users supported, the SUA shall support the 4 possible SCCP protocol classes transparently. The SCCP protocol classes are defined as follows: * Protocol class 0 provides unordered transfer of SCCP-user messages in a connectionless manner. * Protocol class 1 allows the SCCP-user to select the in- sequence delivery of SCCP-user messages in a connectionless manner. * Protocol class 2 allows the bi-directional transfer of SCCP- user messages by setting up a temporary or permanent signaling connection. * Protocol class 3 allows the features of protocol class 2 with the inclusion of flow control. Detection of message loss or mis-sequencing is included. Protocol classes 0 and 1 make up the SCCP connectionless service. Protocol classes 2 and 3 make up the SCCP connection-oriented service. 1.4.3 Native Management Functions The SUA layer may provide management of the underlying SCTP layer to ensure that transport is available according to the degree specified by the SCCP-user application. 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. Loughney, et al. [Page 9] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 1.4.4 Interworking with SCCP Network Management Functions The SUA layer needs to support the following SCCP network management functions: Coord Request Coord Indication Coord Response Coord Confirm State Request State Indication Pcstate Indication 1.4.5 Support for the management between the SG and ASP. The SUA layer should provide interworking with SCCP management functions at the SG for seamless inter-operation between the SCN network and the IP network. It should: *Provide an indication to the SCCP-user at an ASP that a remote SS7 endpoint/peer is unreachable. *Provide an indication to the SCCP-user at an ASP that a remote SS7 endpoint/peer is reachable. *Provide congestion indication to SCCP-user at an ASP. *Provide the initiation of an audit of remote SS7 endpoints at the SG. 1.5 Internal Functions Provided in the SUA Layer 1.5.1 Address Translation and Mapping at the SG SCCP users may present the following options to address their peer endpoints: Global Title DPC + SSN Host Name IP Address(es) Global Titles are an interesting option for addressing. Currently, the ITU does not support translation of Global Titles to IP addresses. However, IP addresses are global in scope. There exist many proprietary schemes for managing SS7 Address Translation to IP addresses, and is considered outside of the scope of this document to specify how this is done. That being said, currently, there is some work within the IETF studying translation of E.164 numbers to Host Names [ENUMS], [E.164- DNS]. Some discussion of address translation should be made to insure interoperability between implementations of the SUA. For further instruction in the use of Global Titles the rules detailed in Annex B of ITU Q.713 [ITU SCCP] or [ANSI SCCP] should be consulted. In many cases, the network operator may have some control over the SCCP-user protocols being transported by SUA. If possible, the Upper Layer can present a Host Name or IP Address, which then can be directly passed to SCTP. Loughney, et al. [Page 10] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 1.5.2 SCTP Stream Mapping The SUA supports SCTP streams. The SG/AS needs to maintain a list of SCTP and SUA-users for mapping purposes. SCCP-users requiring sequenced message transfer need to be sent over a stream supporting sequenced delivery. SUA MUST use stream 0 for SUA management messages. It is recommended that sequenced delivery be in order to preserve the order of management message delivery. 1.6 Definition of SUA Boundaries 1.6.1 Definition of the upper boundary The following primitives are supported between the SUA and an SCCP- user. Connect Request Connect Indication Connect Responding Connect Confirm Data Request Data Indication Expedited Data Request Expedited Data Indication Disconnect Request Disconnect Indication Reset Request Reset Indication Reset Response Reset Confirm 1.6.2 Definition of the lower boundary The upper layer primitives provided by the SCTP are provided in [SCTP]. 2 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. 2.1 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ver | Spare | Message Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Length |A| B | C |D|X| Hop Counter | Loughney, et al. [Page 11] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address Ptr | Destination Address Ptr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mandatory Parameters Ptr | Optional Parameters Ptr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.1.1 SUA Protocol Version The version field (ver) contains the version of the SUA adaptation layer. The supported versions are: 01 SUA version 1.0 2.1.2 Message Types Connectionless Messages Connectionless Data Transfer (CLDT) 0x0501 Connectionless Data Acknowledge (CLDA) 0x0502 Connection-Oriented Messages Connection Request (CORE) 0x0701 Connection Acknowledge (COAK) 0x0702 Release Request (RELRE) 0x0703 Release Complete (RELCO) 0x0704 Reset Confirm (RESCO) 0x0705 Reset Request (RESRE) 0x0706 Connection Oriented Data Transfer (CODT) 0x0707 Connection Oriented Data Acknowledge (CODA) 0x0708 Application Server Process Maintenance (ASPM) Messages ASP Up (ASPUP) 0x0301 ASP Down (ASPDN) 0x0302 Heartbeat(BEAT) 0x0303 ASP Active (ASPAC) 0x0401 ASP Inactive (ASPIA) 0x0402 Notify (NTFY) 0x0404 SUA Management Messages Error (ERR) 0x0000 Audit (AUD) 0x0001 SS7 Signaling Network Management (SSNM) Messages Destination Unavailable (DUNA) 0x0201 Destination Available (DAVA) 0x0202 Destination State Audit (DAUD) 0x0203 SS7 Network Congestion State (SCON) 0x0204 Vendor-Specific Message (VEN) 0xFFFE 2.1.3 Message Length The Message Length defines the length of the message in octets, including the header. Loughney, et al. [Page 12] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 2.1.4 Flags A Error Return option Value Description 0x0 No error message 0x1 Return message on error B Protocol class Value Description 0x0 Class 0 (connectionless service) 0x1 Class 1 (connectionless service) 0x2 Class 2 (connection-oriented service) 0x3 Class 3 (connection-oriented service C priority Value Description 0x0 Least important : 0x7 Highest importance D segmentation Value Description 0x0 No segmentation 0x1 Segmentation E Hop Counter Value Description 0x0 : 0x15 Maximum number of GTT 0x16 : Spare 0x255 2.1.5 Pointer Usage The pointer will point to the byte at the start of the parameter. If the pointer value is 0, then the parameter is not present in the message. 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +---------------+---------------+ | Pointer MSB | Pointer LSB | +---------------+---------------+ / . . . / \ \ +---------------+---------------+ | X + Pointer | | +---------------+---------------+ 2.2 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. Loughney, et al. [Page 13] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 2.2.1 Connectionless Data Transfer This message transfers data between one SUA to another. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Originating Address Mandatory Destination Address Mandatory Data Mandatory Implementation note: This message covers the following SCCP messages: unitdata (UDT), extended unitdata (XUDT), long unitdata (LUDT). 2.2.2 Connectionless Data Acknowledge This message is used to acknowledge receipt of data by the peer and/or report errors. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / Loughney, et al. [Page 14] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Originating Address Mandatory Destination Address Mandatory Data Optional Fixed Length Parameters Cause Mandatory Implementation note: This message covers the following SCCP messages: protocol data unit error (ERR), long unitdata service (LUDTS), unitdata service (UDTS), extended unitdata service (XUDTS). 2.3 Connection Oriented Messages 2.3.1 Connection Oriented Data Transfer This message transfers data between one SUA to another for connection oriented service. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Sequence number Optional Destination Reference Number Mandatory Variable Length Parameters Data Mandatory Implementation note: This message covers the following SCCP messages: data form 1 (DT1), data form 2 (DT2), expedited data (ED). 2.3.2 Connection Oriented Data Acknowledge This message is used to acknowledge receipt of data by the peer and/or report errors. 0 1 2 3 Loughney, et al. [Page 15] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Sequence number Optional Destination Reference Number Mandatory Implementation note: This message covers the following SCCP messages: data acknowledgement (AK), expedited data acknowledgement (EA). 2.3.3 Connect Request 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Source Reference Number Mandatory Variable Length Parameters Data Optional 2.3.4 Connection Acknowledge This message is used to acknowledge and/or refuse a connection request between to peer endpoints. Loughney, et al. [Page 16] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Destination Reference Number Mandatory *1 Source Reference Number Mandatory *1 Cause Mandatory *2 Variable Length Parameters Data Optional *1 Mandatory for connection confirmation, it is not needed in the case that the connection is refused. *2 Mandatory in the case that the connection is refused. Implementation note: This message covers the following SCCP messages: connection confirm (CC), connection refused (CREF). 2.3.5 Release Request 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 17] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Cause Mandatory Variable Length Parameters Data Optional 2.3.6 Release Complete 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 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Destination Reference Number Mandatory Source Reference Number Mandatory 2.3.7 Reset Request This message is used to indicate that the sending SCCP/SUA wants to initiate a reset procedure (re-initialization of sequence numbers) the peer endpoint. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 18] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Destination Reference Number Mandatory Source Reference Number Mandatory Cause Mandatory 2.3.8 Reset Confirm 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Destination Reference Number Mandatory Source Reference Number Mandatory 2.4 SS7 Signaling Network Management Messages 2.4.1 Destination Unavailable The DUNA message is sent from the SG to all concerned ASPs to indicate that the SG has determined that an SS7 destination is unreachable. The SUA-User at the ASP is expected to stop traffic to the affected destination through the SG initiating the DUNA. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol id | Loughney, et al. [Page 19] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Protocol ID Optional Network Appearance Optional Variable Length Parameters Source Address Mandatory Destination Address Mandatory Info String Optional Note: The Source Address refers to the address of the sender of the DUNA. The Destination Address refers to the address of the unreachable destination. 2.4.2 Destination Available The DAVA message is sent from the SG to all concerned ASPs to indicate that the SG has determined that an SS7 destination is now reachable. The ASP MTP3-User protocol is expected to resume traffic to the affected destination through the SG initiating the DUNA. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Loughney, et al. [Page 20] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 Protocol ID Optional Network Appearance Optional Variable Length Parameters Source Address Mandatory Destination Address Mandatory Info String Optional Note: The Source Address refers to the address of the sender of the DAVA. The Destination Address refers to the address of the destination which is now reachable. 2.4.3 Destination State Audit The DAUD message can be sent from the ASP to the SG to query the availability state of the SS7 routes to an affected destination. A DAUD may be sent periodically after the ASP has received a DUNA, until a DAVA is received. The DAUD can also be sent when an ASP recovers from isolation from the SG. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Protocol ID Optional Network Appearance Optional Variable Length Parameters Source Address Mandatory Destination Address Mandatory Info String Optional Note: The Source Address refers to the address of the sender of the DAUD. The Destination Address refers to the address of the destination who's state is being audited. Loughney, et al. [Page 21] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 2.4.4 SS7 Network Congestion The SCON message can be sent from the SG to all concerned ASPs to indicate that the congestion level in the SS7 network to a specified destination has changed. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | congestion level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Protocol ID Optional Network Appearance Optional Congestion Level Optional Variable Length Parameters Source Address Mandatory Destination Address Mandatory Info String Optional Note: The Source Address refers to the address of the sender of the SCON. The Destination Address refers to the address of the unreachable destination. Implementation note: This message covers the following SCCP message: subsystem congested (SSC). Loughney, et al. [Page 22] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 2.5 Application Server Process Maintenance Messages 2.5.1 ASP Up (ASPUP) The ASP UP (ASPUP) message is used to indicate to a remote SUA peer that the Adaptation layer is ready to receive traffic or maintenance messages. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ASP Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ALI | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters ASP Capabilities Manditory (see section 2.8.10) Adaptation Layer Identifier Optional Variable Length Parameters Info String Optional 2.5.2 ASP Down (ASPDN) The ASP Down (ASPDN) message is used to indicate to a remote SUA peer that the adaptation layer is not ready to receive traffic or maintenance messages. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 23] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | reason code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Reason Code Mandatory Variable Length Parameters Info String Optional The Reason parameter indicates the reason that the remote SUA adaptation layer is unavailable. The valid values for Reason are shown in the following table. Value Description 0x1 Processor Outage 0x2 Management Inhibit Implementation note: This message covers the following SCCP message: subsystem-prohibited (SSP). 2.5.3 Heartbeat (BEAT) The Heartbeat message is optionally used to ensure that the SUA peers are still available to each other. It is recommended for use when the SUA runs over a transport layer other than the SCTP, which has its own heartbeat. The BEAT message contains no parameters. 2.5.4 ASP Active (ASPAC) The ASPAC message is sent by an ASP to indicate to an SG/AS that it is Active and ready to be used. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 24] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Routing Context Mandatory Info String Optional Implementation note: This message covers the following SCCP message: subsystem-allowed (SSA). 2.5.5 ASP Inactive (ASPIA) The ASPIA message is sent by an ASP to indicate to an SG/AS that it is no longer an active ASP to be used from within a list of ASPs. The SG/AS will respond with an ASPIA message and either discard incoming messages or buffer for a timed period and then discard. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Routing Context Optional Info String Optional Loughney, et al. [Page 25] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 Implementation note: This message covers the following SCCP message: subsystem-out-of- service-request (SOR). 2.5.6 ASP Inactive Ack (ASPIAK) The ASPIAK message is sent by the SG/AS in response to an ASPIA to the sending ASP that it acknowledges the ASPIA. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Routing Context Optional Info String Optional Implementation note: This message covers the following SCCP message: subsystem-out-of- service-grant (SOG). 2.5.7 Notify (NTFY) The NTFY message is sent by an AS to indicate any change of status in the AS or ASP to an ASP. AS sends this message to all concerned endpoints. The format for the NTFY 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 26] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The NTFY message contains the following parameters: Fixed Length Parameters Status Type Mandatory Variable Length Parameters Routing Context Optional Info String Optional 2.6 Management Messages These messages are used for managing SUA and the representations of the SCCP subsystems in the SUA layer. 2.6.1 Error (ERR) The ERR message is sent when an invalid value is found in an incoming message. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ver | Spare | Message Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Length |A| B | C |D|X| Hop Counter | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address Ptr | Destination Address Ptr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mandatory Parameters Ptr | Optional Parameters Ptr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ Loughney, et al. [Page 27] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Cause | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Fixed Length Parameters Cause Mandatory Variable Length Parameters Source Address Mandatory Destination Address Mandatory Data Optional The Error Code can be one of the following values: Invalid Version 0x1 Invalid Network Appearance 0x2 Invalid SCN Version 0x3 Invalid Adaptation Layer Identifier 0x4 Invalid Stream Identifier 0x5 Invalid Message Type 0x6 2.6.2 Audit This message is used to audit the current state of 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Variable Length Parameters Source Address Mandatory Loughney, et al. [Page 28] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 Destination Address Mandatory Data Optional Implementation note: This message covers the following SCCP messages: inactivity test (IT), subsystem-status-test (SST). 2.7 Vendor Specific Message This is to allow vendors to support their own extended message not defined by the IETF. It MUST not affect the operation of the SUA. Endpoints not equipped to interpret the vendor-specific messages sent by a remote endpoint MUST ignore it (although it may be reported). Endpoints that do not receive desired vendor-specific information SHOULD make an attempt to operate without it, although they may do so (and report they are doing so) in a degraded mode. A summary of the Vendor-specific extension format is shown below. The fields are transmitted from left to right. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Type = 0xFFFE | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vendor-Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ \ \ / Parameter Value / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: 16 bit u_int 0xFFFE for all Vendor-Specific parameters. Length: 16 bit u_int Indicate the size of the parameter in octets, including the Type, Length, Vendor-Id, and Value fields. Vendor-Id: 32 bit u_int The high-order octet is 0 and the low-order 3 octets are the SMI Network Management Private Enterprise Code of the Vendor in network byte order, as defined in the Assigned Numbers (RFC 1700). Value: variable length The Value field is one or more octets. The actual format of the information is site or application specific, and a robust implementation SHOULD support the field as undistinguished octets. The codification of the range of allowed usage of this field is Loughney, et al. [Page 29] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 outside the scope of this specification. It SHOULD be encoded as a sequence of vendor type / vendor length / value fields, as follows. The parameter field is dependent on the vendor's definition of that attribute. An example encoding of the Vendor-Specific attribute using this method 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Parameter Type = 0xFFFE | Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vendor-Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VS-Type | VS-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / VS-Value / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ VS-Type: 16 bit u_int This field identifies the parameter included in the VS-Value field. It is assigned by the vendor. VS-Length: 16 bit u_int This field is the length of the vendor-specific parameter and includes the VS-Type, VS-Length and VS-Value (if included) fields. VS-Value: Variable Length This field contains the parameter identified by the VS-Type field. It's meaning is identified by the vendor. 2.8 Fixed Length Parameters Parameter Name Parameter ID ============== ============ Sequence Number 0x0002 Source Reference Number 0x0003 Destination Reference Number 0x0004 Cause 0x0007 Protocol Identifier 0x0008 Network Appearance 0x0009 Congestion Level 0x000C Adaptation Layer Identifier 0x000D ASP ID 0x000E ASP Capabilities 0x000F Status 0x0010 2.8.1 Sequence Number 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 30] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 | Sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.2 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | source reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destination reference number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.4 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | reason code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reason code may be one of the following reasons: Invalid Version 0x1 Invalid Network Appearance 0x2 Invalid SCN Version 0x3 Invalid Adaptation Layer Identifier 0x4 Invalid Stream Identifier 0x5 Invalid Message Type 0x6 2.8.5 Protocol Identifier The Protocol Identifier parameter identifies the SCCP version/variant. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | protocol id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.6 Network Appearance The Network Appearance parameter identifies the SS7 network context for the message, for the purposes of logically separating the signaling traffic between the SG and the Application Server Processes Loughney, et al. [Page 31] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 over common SCTP Associations. An example is where an SG is logically partitioned to appear as an element in four different national SS7 networks. A Network Appearance implicitly defines the SS7 Destination Point Code used, the SS7 Network Indicator value and SCCP/SCCP-User protocol type/variant/version used within the SS7 network partition. Where an SG operates in the context of a single SS7 network, or individual SCTP associations are dedicated to each SS7 network appearance, the Network Appearance parameter is not required. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | network appearance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.7 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | congestion level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The valid values for the optional Congestion Level parameter are shown in the following table. Value Description 00 No Congestion or Undefined 01 Congestion Level 1 02 Congestion Level 2 03 Congestion Level 3 2.8.8 Adaptation Layer 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ALI | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The optional Adaptation Layer Identifier (ALI) is a string that identifies the adaptation layer. This string MUST be set to "SUA" which results in a length of 3. The ALI would normally only be used in the initial ASP Up message across a new SCTP association to ensure both peers are assuming the same adaptation layer protocol. 2.8.9 ASP ID 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 32] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 | ASP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.8.10 ASP Capabilities This parameter is used so that the ASP can report it's capabilities for supporting different protocol classes and interworking scenarios. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1|0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | reserved |0 0 0 0|a|b|c|d| interworking | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Flags a - Protocol Class 3 b - Protocol Class 2 c - Protocol Class 1 d - Protocol Class 0 0 indicates no support for the Protocol Class. Interworking Values 0x0 indicates no interworking with SS7 Networks. 0x1 indicates IP Signaling Endpoint. 0x2 indicates Signaling Gateway. 2.8.11 Status This parameter is used so that the ASP can report it's capabilities for supporting different protocol classes and interworking scenarios. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status Type | Status Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Status Type parameter identifies the type of the status that is being notified. The valid values are shown in the following table. Value Description 0x1 AS_STATE_CHANGE 0x2 ASP_STATE_CHANGE The Status Id parameter identifies the status that is being notified. The valid values are shown in the following table. If the Status Type is AS_STATE_CHANGE Value Description 0x1 AS_DOWN 0x2 AS_UP Loughney, et al. [Page 33] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 0x3 AS_PART_ACTIVE 0x4 AS_ACTIVE 0x5 AS_PENDING If the Status Type is ASP_STATE_CHANGE Value Description 0x1 ASP_DOWN 0x2 ASP_UP 0x3 ASP_ACT_NEW 0x4 ASP_ACT_OLD 0x5 AS_ACTIVE 2.9 Variable Length Paramters Parameter Name Parameter ID ============== ============ Data 0x0001 Source Address 0x0005 Destination Address 0x0006 Info String 0x000A Routing Context 0x000B 2.9.1 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / data / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.9.2 Source Address (=CLG) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Source Address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Type of Address field is used to aid in the identification of the type of address. If this field is set to 0, then the address field needs to be analized. Type of Address Unknown/Undeterminable 0x00000000 SS7 Point Code 0x00000001 Global Title 0x00000002 Host Name 0x00000003 IPv4 Address 0x00000004 IPv6 Address 0x00000005 Loughney, et al. [Page 34] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 2.9.3 Destination Address (=CLD) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| Parameter Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type of Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / destination address / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Type of Address field is used to aid in the identification of the type of address. If this field is set to 0, then the address field needs to be analized. Type of Address Unknown/Undeterminable 0x00000000 SS7 Point Code 0x00000001 Global Title 0x00000002 Host Name 0x00000003 IPv4 Address 0x00000004 IPv6 Address 0x00000005 2.9.4 Info String The INFO String parameter can carry any meaningful 8-BIT ASCII character string along with the message. Length of the INFO String parameter is from 0 to 255 characters. No procedures are presently identified for its use but the INFO String may be used by Operators for debugging purposes. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / info string / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2.9.5 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0| length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / Routing Context / \ \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Loughney, et al. [Page 35] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 The Type parameter identifies the message as an Over-ride or Load- share Active message. The valid values for Type are shown in the following table. Value Description 0x1 Over-ride 0x2 Load-share Within a particular Routing Context, only one Type can be used. The optional Routing Context parameter contains (a list of) integers indexing the Application Server traffic that the sending ASP is configured to receive. There is one-to-one relationship between an index entry and an AS Name. Because an AS can only appear in one Network Appearance, the Network Appearance parameter is not required in the ASPAC message An Application Server Process may be configured to process traffic for more than one logical Application Server. From the perspective of an ASP, a Routing Context defines a range of signaling traffic that the ASP is currently configured to receive from the SG. 3 Procedures The SUA layer needs to respond to various local primitives it receives from other layers as well as the messages that it receives from the peer SUA layers. This section describes the SCU procedures in response to these events. 3.1 Peer Message Procedures On receiving a message, the SUA layer performs address translation and mapping (if needed), to determine the appropriate Application Server Process (ASP). The appropriate ASP can be determined based on the information in the incoming message, local load sharing information, etc. The appropriate SUA message is then constructed and sent to the appropriate endpoint, via the correct SCTP association. 3.2 Signaling Gateway Related Procedures These support the SUA transport of SCCP-User/SCCP boundary primitives. On receiving a SCCP message at the SG, the SUA layer performs address translation and mapping, to determine the appropriate Application Server Process (ASP). The appropriate ASP can be determined based on the information in the incoming message, local load sharing information, etc. The appropriate SUA message is then constructed and sent to the appropriate endpoint, via the correct SCTP association. The SUA needs to setup and maintain the appropriate SCTP association to the selected endpoint. SUA also manages the usage SCTP streams. 3.3 Layer Management Procedures The SUA layer needs to send and receive layer management messages. 3.4 SCTP Management Procedures Loughney, et al. [Page 36] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 These procedures support the SUA management of SCTP Associations and ASP Paths between SGs and ASPs. 3.4.1 State Maintenance The SUA layer on at each AS needs to maintain the state of each ASP under its control, as a way to manage the state and connections of the local ASPs. At a SG, the state of each ASP is needed as input to the SGs address translation and mapping function. 3.4.1.1 ASP States The state of each ASP is maintained in the SUA layer at the controlling AS. The state of an ASP changes due to events. The events include: * Reception of messages from that ASP's SUA layer * Reception of messages from a different ASP's SUA layer * Reception of indications from the SCTP layer * Switch over timer triggers The ASP state transition diagram is shown in Figure 4. The possible states of an ASP are: ASP-DOWN: The Application Server Process is unavailable. Initially all ASPs will be in this state. ASP-UP: The Application Server Process is available but application traffic is stopped. ASP-ACTIVE: The Application Server Process is available and application traffic is active. +-------------+ |-------->| | | | ASP-ACTIVE | | | | | | | | +-------------+ | ^ | | ASP | | ASP | Active | | Inactive | | v | +-------------+ | | | ASP Down / | | | SCTP CDI | | ASP-UP | | | | | | | | +-------------+ | ^ | | ASP | | ASP Down / | Up | | SCTP CDI | | v | +-------------+ | | | |-------->| | | ASP-DOWN | Loughney, et al. [Page 37] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 | | | | +-------------+ Figure 4: ASP State Transition Diagram SCTP CDI: The local SCTP layer's Communication Down Indication to the Upper Layer Protocol. The local SCTP will send this indication when it detects the loss of connectivity to the ASP's SCTP layer. Ts: Switch over Timer Triggers 3.4.1.2 AS States The state of the AS is maintained in the SUA layer. The state of an AS changes due to events. These events include: * ASP state transitions * Recovery timer triggers The possible states of an AS are: AS-DOWN: The Application Server is unavailable. This state implies that all related ASPs are in the ASP-DOWN state for this AS. Initially the AS will be in this state. AS-UP: The Application Server is available but no application traffic is active (i.e., one or more related ASPs are in the ASP-UP state, but none in the ASP-Active state). AS-ACTIVE: The Application Server is available and application traffic is active. This state implies that one ASP is in the ASP-ACTIVE state. AS-PENDING: An active ASP has transitioned from active to inactive or down and it was the last remaining active ASP in the AS. A recovery timer T(r) will be started and all incoming SCN messages will be queued by the SG. If an ASP becomes active before T(r) expires, the AS will move to AS-ACTIVE state and all the queued messages will be sent to the active ASP. If T(r) expires before an ASP becomes active, the SG stops queuing messages and discards all previously queued messages. The AS will move to AS-UP if at least one ASP is in ASP-UP state, otherwise it will move to AS-DOWN state. +----------+ one ASP trans ACTIVE +-------------+ | |------------------------>| | | AS-UP | | AS-ACTIVE | | | | | | |< -| | +----------+ \ / +-------------+ ^ | \ Tr Trigger / ^ | | | \ at least one / | | | | \ ASP in UP / | | Loughney, et al. [Page 38] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 | | \ / | | | | \ / | | | | \ /---/ | | one ASP | | \ / one ASP | | ACTIVE ASP trans | | all ASP \-/----\ trans | | trans to UP or to UP | | trans to / \ ACTIVE | | ACTIVE ASP | | DOWN / \ | | SCTP CDI | | / \ | | | | / \ | | | | /all ASP \ | | | v / trans to \ | v +----------+ / DOWN \ +-------------+ | |<--/ -| | | AS-DOWN | | AS-PENDING | | | | (queuing) | | |<------------------------| | +----------+ Tr Trigger no ASP +-------------+ in UP state or prev ACTIVE ASP trans to DOWN state Tr = Recovery Timer Figure 5: AS State Transition Diagram 3.4.2 ASPM procedures for primitives Before the establishment of an SCTP association the ASP state at both the AS and ASP is assumed to be "Down". When the SUA layer receives an M-SCTP ESTABLISH request primitive from the Layer Management, the SUA layer will try to establish an SCTP association with the remote SUA peer. Upon reception of an eventual SCTP-Communication Up confirm primitive from the SCTP, the SUA layer will invoke the primitive M-SCTP ESTABLISH confirm to the Layer Management. Alternatively, if the remote SUA-peer establishes the SCTP association first, the SUA layer will receive an SCTP Communication Up indication primitive from the SCTP. The SUA layer will then invoke the primitive M-SCTP ESTABLISH indication to the Layer Management. Once the SCTP association is established, The SUA layer at an ASP will then find out the state of its local SUA-user from the Layer Management using the primitive M-ASP STATUS. Based on the status of the local SUA-User, the local ASP SUA Application Server Process Maintenance (ASPM) function will initiate the ASPM procedures, using the ASP-Up/-Down/-Active/-Inactive messages to convey the ASP-state to the SG - see Section 3.3.3. If the SUA layer subsequently receives an SCTP-Communication Down indication from the underlying SCTP layer, it will inform the Layer Management by invoking the M-SCTP STATUS indication primitive. The state of the ASP will be moved to "Down." At an ASP, the Layer Management may try to reestablish the SCTP association using M-SCTP ESTABLISH request primitive. Loughney, et al. [Page 39] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 3.4.3 ASPM procedures for peer-to-peer messages 3.4.3.1 ASP-Up The AS will mark the path as up if an explicit ASP UP (ASPUP) message is received and internally the path is allowed to come up (i.e., not in a locked local maintenance state). An ASP UP (ASPUP) message will be sent to acknowledge the received ASPUP. The SG will respond to a ASPUP with a ASPDN message if the path is in a locked maintenance state. The receiving ASP will send a ASPUP message in response to a received ASPUP message from the ASP even if that path was already marked as UP. The paths are controlled by the ASP. The ASP will send ASPUP messages every t(a) seconds until the path comes up (i.e. until it receives a ASPUP message from the remote peer for that path). The ASP may decide to reduce the frequency (say to every 5 seconds) if the an acknowledgement is not received after a few tries. The ASP should wait for the ASPUP message from the remote peer before transmitting ASP maintenance messages (ASPIA or ASPAC) or SUA messages or it will risk message loss. 3.4.3.2 ASP Down The AS will mark the ASP as down and send a ASPDN message to the ASP if one of the following events occur: - an ASP Down(ASPDN) message is received from the ASP, - the ASP is locked by local maintenance. The AS will also send a ASPDN message when the ASP is already down and a ASPDN) message is received from the ASP. The ASP will send ASPDN whenever it wants to take down a ASP. Since it is possible for ASPDN messages and responses can be lost (for example, during a node failover), the ASP can send ASPDN messages every t(a) seconds until the path comes down (i.e. until it receives a ASPDN message from the remote peer for that path). 3.4.3.3 ASP Version Control If a ASP Up message with an unknown version is received, the receiving end will respond with an Error message. This will indicate to the sender which version the receiving node supports. This is useful when protocol version upgrades are being performed. A node with the newer version should support the older versions used on other nodes it is communicating with. The version field in the Error message header associated will indicate the version supported by the node. 3.4.3.4 ASP Active Loughney, et al. [Page 40] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 When an ASP Active (ASPAC) message is received, the ASP will start traffic routing to that ASP. Reception of a ASPAC message overrides any previous ASPAC messages and results in the ASP associated with the ASPAC message to become the newly active ASP. 3.4.3.5 ASP Inactive When a ASPIA message is received, message transmission to that ASP ceases. The ASP will either discard all incoming messages or start buffering the incoming messages for T(r)seconds after which messages will be discarded. If the ASP is down, all of the Paths that were supported by that ASP are, by default, down. 4 Examples of SUA Procedures 4.1 Establishment of Association 4.1.1 SG Architecture SG ASP1 ASP2 (Primary) (Backup) | | | <----ASP Up--------+ | +----ASP Up (Ack)--> | | | | <-----------------------ASP Up---------+ +-----------------------ASP Up (Ack)---> | | | <----ASP Active----+ | +-ASP Active Ack---> | | | | 4.1.2 IP to IP Architecture ASP1 (AS1) ASP1 (AS2) ASP2 (AS2) (Primary) (Backup) | | | <----ASP Up--------+ | +----ASP Up (Ack)--> | | | | <-----------------------ASP Up---------+ +-----------------------ASP Up (Ack)---> | | | <----ASP Active----+ | +-ASP Active Ack---> | | | | 4.2 ASP fail-over Procedures SG ASP1 ASP2 | | | |<-----ASP Inactive-------| | |---NTFY(ASP Inactive)--->| | |--------------------NTFY(ASP-Inactive) (Optional)-->| | | | |<------------------------------ ASP Active----------| Loughney, et al. [Page 41] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 |-----------------------------NTFY(ASP-Active)------>| | | 4.3 SUA/SCCP-User Boundary Examples 4.3.1 Data Transfer This is an example of data transfer, assuming associations are already established. SEP SG SG ASP ASP SCCP SUA SCTP SCTP SUA | | | | | +----UDT-----> | | | | +---Send----> | | | |.. . . . . . . CLDT . . . . . . . .> | | +---data----> | | | | +-data arr--> | | | <-rec data--| | | <---sack----+ | | <-data arr--+ | | | +-rec data--> | | | < . . . . . . . CLDA . . . . . . . .. | | | | | 5 Security 5.1 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. 5.2 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. Loughney, et al. [Page 42] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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. In such a case, it is recommended that IPSEC is used to ensure confidentiality of user payload. Consult [2409] for more information on configuring IPSEC services. 5.3 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. 6 IANA Considerations 6.1 SCTP Protocol ID A request will be made to IANA to assign protocol IDs. A protocol ID for the SUA will be registered. The protocol ID is included in each SCTP data chunk, to indicate which protocol SCTP is carrying. This protocol 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. 6.2 Port Number A request will be made to IANA to assign an SUA Port Number. This Port Number is the port which the SG listen to when receiving SCTP datagrams. 7 Timer Values Ta 2 seconds Tr 2 seconds 8 Acknowledgements The authors would like to thank Lode Coene, Marja-Liisa Hamalainen and Markus Maanoja for their insightful comments and suggestions. Funding for the RFC editor function is currently provided by the Internet Society. 9 Authors' Addresses John Loughney Nokia Research Center PO Box 407 FIN-00045 Nokia Group Finland john.loughney@nokia.com Greg Sidebottom Nortel Networks 3685 Richmond Rd, Nepean, Ontario, Canada K2H 5B7 Loughney, et al. [Page 43] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 10 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 V3.0.0 (2000-01) 'Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRAN Iu Interface RANAP Signalling' [SCTP] Stream Control Transport Protocol , June 2000, Work in Progress. [M3UA] MTP3-User Adaptation Layer , March 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 V3.0.0 (2000-01) "Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; UTRAN Iur Interface General Aspects and Principles" [2196] RFC 2196, "Site Security Handbook", B. Fraser Ed., September 1997. [ENUM] "ENUM Requirements" , December 1999, Work in Progress. [E.164-DNS] "ENUM Service Specific Provisioning: Principles of Operation" , , April 2000, Work in Progress. Loughney, et al. [Page 44] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 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 - - - - CLDA UDTS Unitdata service X X - - - - CLDA XUDTS Extended unitdata serv. X X - - - - CLDA LUDTS Long unitdata service X X - - - - Connection-Oriented Messages CODT DT1 Data form 1 - - X - - - CODT DT2 Data form 2 - - - X - - CODT ED Expedited data - - - X - - CODA AK Data acknowledgement - - - X - - CODA EA Expedited data ack. - - - X - - CORE CR Connection request - - X X - - COAK CC Connection confirm - - X X - - COAK CREF Connection refused - - X X - - RELRE RLSD Released - - X X - - RELCO RLC Release complete - - X X - - RESRE RSR Reset request - - - X - - RESCO RSC Reset confirm - - - X - - General Protocol Messages ERR ERR Protocol data unit error - - X X - X AUD IT Inactivity test - - X X - X VEN n/a n/a - - - - - X SS7 MGT Messages DUNA SSP subsystem-prohibited - - - - X - DAVA SSA subsystem-allowed - - - - X - DAUD SST subsystem-status-test - - - - X - SCON SSC SCCP/subsystem-congested - - - - X - SOR subsystem-oos-req - - - - X - SOG subsystem-oos-grant - - - - X - SUA MGT Messages ASPUP n/a n/a - - - - - X ASPDN n/a n/a - - - - - X ASPAC n/a n/a - - - - - X ASPIA n/a n/a - - - - - X NTFY n/a n/a - - - - - X - = Message not applicable for this protocol class. X = Message applicable for this protocol class. n/a = not applicable Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. Loughney, et al. [Page 45] Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000 This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Loughney, et al. [Page 46]