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Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: Under certain scenarios, such as back-to-back connections without redundancy requirements, the SCTP functions above MAY NOT be a requirement and TCP can be used as the underlying common transport protocol. == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: The Affected Destinations parameter can be used to indicate congestion of multiple destinations or ranges of destinations. However, an SCON message MUST not be delayed in order to "collect" individual congested destinations into a single SCON message as any delay might affect the timing of congestion indications to the M3UA Users. One use for including a range of Congested DPCs is when the SG supports an ANSI cluster route set to the SS7 network that becomes congested due to outgoing link set congestion. == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: The SCTP Payload Protocol Identifier value "3" SHOULD be included in each SCTP DATA chunk, to indicate that the SCTP is carrying the M3UA protocol. The value "0" (unspecified) is also allowed but any other values MUST not be used. This Payload Protocol Identifier is not directly used by SCTP but MAY be used by certain network entities to identify the type of information being carried in a DATA chunk. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. 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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group Greg Sidebottom 2 INTERNET-DRAFT Guy Mousseau 3 Nortel Networks 4 Lyndon Ong 5 Ciena 6 Ian Rytina 7 Ericsson 8 Hanns Juergen Schwarzbauer 9 Siemens 10 Klaus Gradischnig 11 NeuStar 12 Ken Morneault 13 Cisco 14 Mallesh Kalla 15 Telcordia 16 Normand Glaude 17 Performance Technologies 19 Expires in six months Jul 2001 21 SS7 MTP3-User Adaptation Layer (M3UA) 22 24 Status of This Memo 26 This document is an Internet-Draft and is in full conformance with all 27 provisions of Section 10 of RFC 2026. Internet-Drafts are working 28 documents of the Internet Engineering Task Force (IETF), its areas, and 29 its working groups. Note that other groups may also distribute working 30 documents as Internet-Drafts. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference material 35 or to cite them other than as 'work in progress.' 37 The list of current Internet-Drafts can be accessed at 38 http://www.ietf.org/1id-abstracts.html 40 The list of Internet-Draft Shadow Directories can be accessed at 41 http://www.ietf.org/shadow.html. 43 To learn the current status of any Internet-Draft, please check the 44 '1id-abstracts.txt' listing contained in the Internet- Drafts Shadow 45 Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), 46 munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or 47 ftp.isi.edu (US West Coast). 49 Abstract 51 This Internet Draft defines a protocol for supporting the transport of 52 any SS7 MTP3-User signalling (e.g., ISUP and SCCP messages) over IP 53 using the services of the Stream Control Transmission Protocol. Also, 54 provision is made for protocol elements that enable a seamless 55 operation of the MTP3-User peers in the SS7 and IP domains. This 56 protocol would be used between a Signalling Gateway (SG) and a Media 57 Gateway Controller (MGC) or IP-resident Database. It is assumed that 58 the SG receives SS7 signalling over a standard SS7 interface using the 59 SS7 Message Transfer Part (MTP) to provide transport. 61 TABLE OF CONTENTS 63 1. Introduction.......................................................4 64 1.1 Scope.........................................................4 65 1.2 Terminology...................................................4 66 1.3 M3UA Overview.................................................6 67 1.4 Functional Areas.............................................12 68 1.5 Sample Configurations........................................21 69 1.6 Definition of M3UA Boundaries................................24 70 2. Conventions.......................................................28 71 3. M3UA Protocol Elements............................................28 72 3.1 Common Message Header........................................28 73 3.2 Variable-Length Parameter....................................31 74 3.3 Transfer Messages............................................32 75 3.4 SS7 Signalling Network management (SSNM) Messages............35 76 3.5 ASP State Maintenance (ASPM) Messages........................43 77 3.6 Routing Key Management (RKM) Messages........................46 78 3.7 ASP Traffic Maintenance (ASPTM) Messages.....................55 79 3.8 Management(MGMT) Messages....................................60 80 4. Procedures........................................................64 81 4.1 Procedures to Support the M3UA-User and Layer Management 82 Layers.......................................................64 83 4.2 Procedures to Support the Management of SCTP Associations 84 with M3UA Peers..............................................67 85 4.3 Procedures to support the Unavailability or Congestion 86 Status of SS7 Destinations...................................81 87 4.4 MTP3 Restart.................................................83 88 5. Examples of M3UA Procedures.......................................84 89 5.1 Establishment of Association and Traffic 90 Between SGs and ASPs.........................................84 91 5.2 ASP traffic Fail-over Examples...............................89 92 5.3 Normal Withdrawal of an ASP from an Application Server 93 and Tear-down of an Association..............................90 94 5.4.M3UA/MTP3-User Boundary Examples.............................91 95 6. Security..........................................................95 96 6.1 Introduction.................................................95 97 6.2 Threats......................................................95 98 6.3 Protecting Confidentiality...................................95 99 7. IANA Considerations...............................................96 100 7.1 SCTP Payload Protocol Identifier.............................96 101 7.2 M3UA Protocol Extensions.....................................96 102 8. Acknowledgements..................................................97 103 9. References........................................................97 104 10. Bibliography....................................................99 105 11. Author's Addresses..............................................99 106 1. Introduction 108 1.1 Scope 110 There is a need for Switched Circuit Network (SCN) signalling protocol 111 delivery from an SS7 Signalling Gateway (SG) to a Media Gateway 112 Controller (MGC) or IP-resident Database as described in the Framework 113 Architecture for Signalling Transport [1]. The delivery mechanism 114 SHOULD meet the following criteria: 116 * Support for the transfer of all SS7 MTP3-User Part messages (e.g., 117 ISUP, SCCP, TUP, etc.) 118 * Support for the seamless operation of MTP3-User protocol peers 119 * Support for the management of SCTP transport associations and 120 traffic between an SG and one or more MGCs or IP-resident Databases 121 * Support for MGC or IP-resident Database process fail-over and load- 122 sharing 123 * Support for the asynchronous reporting of status changes to 124 management 126 In simplistic transport terms, the SG will terminate SS7 MTP2 and MTP3 127 protocol layers and deliver ISUP, SCCP and/or any other MTP3-User 128 protocol messages, as well as certain MTP network management events, 129 over SCTP transport associations to MTP3-User peers in MGCs or IP- 130 resident Databases. 132 1.2 Terminology 134 Application Server (AS) - A logical entity serving a specific Routing 135 Key. An example of an Application Server is a virtual switch element 136 handling all call processing for a unique range of PSTN trunks, 137 identified by an SS7 SIO/DPC/OPC/CIC_range. Another example is a 138 virtual database element, handling all HLR transactions for a 139 particular SS7 DPC/OPC/SCCP_SSN combination. The AS contains a set of 140 one or more unique Application Server Processes, of which one or more 141 is normally actively processing traffic. An AS is contained within a 142 single Network Appearance. Note that there is a 1:1 relationship 143 between an AS and a Routing Key. 145 Application Server Process (ASP) - A process instance of an Application 146 Server. An Application Server Process serves as an active or back-up 147 process of an Application Server (e.g., part of a distributed virtual 148 switch or database). Examples of ASPs are processes (or process 149 instances) of MGCs, IP SCPs or IP HLRs. An ASP contains an SCTP end- 150 point and may be configured to process signalling traffic within more 151 than one Application Server. 153 Association - An association refers to an SCTP association. The 154 association provides the transport for the delivery of MTP3-User 155 protocol data units and M3UA adaptation layer peer messages. 157 IP Server Process (IPSP) - A process instance of an IP-based 158 application. An IPSP is essentially the same as an ASP, except that it 159 uses M3UA in a point-to-point fashion. Conceptually, an IPSP does not 160 use the services of a Signalling Gateway. 162 Signalling Gateway Process (SGP) - A process instance of a Signalling 163 Gateway. It serves as an active, back-up or load-sharing process of a 164 Signalling Gateway. 166 Signalling Gateway - An SG is a signaling agent that receives/sends SCN 167 native signaling at the edge of the IP network [1]. An SG appears to 168 the SS7 network as an SS7 Signalling Point. An SG contains a set of one 169 or more unique Signalling Gateway Processes, of which one or more is 170 normally actively processing traffic. Where an SG contains more than 171 one SGP, the SG is a logical entity and the contained SGPs must be 172 coordinated into a single management view to the SS7 network and to the 173 supported Application Servers. 175 Signalling Process - A process instance that uses M3UA to communicate 176 with other signalling process. An ASP, an SGP and an IPSP are all 177 signalling processes. 179 Routing Key: A Routing Key describes a set of SS7 parameters and 180 parameter values that uniquely define the range of signalling traffic 181 to be handled by a particular Application Server. Parameters within the 182 Routing Key cannot extend across more than a single SS7 Destination 183 Point Code. 185 Routing Context - A value that uniquely identifies a Routing Key. 186 Routing Context values are either configured using a configuration 187 management interface, or by using the routing key management procedures 188 defined in this document. 190 Fail-over - The capability to re-route signalling traffic as required 191 to an alternate Application Server Process, or group of ASPs, within an 192 Application Server in the event of failure or unavailability of a 193 currently used Application Server Process. Fail-over also applies upon 194 the return to service of a previously unavailable Application Server 195 Process. 197 Signalling Point Management Cluster (SPMC) - The complete set of 198 Application Servers represented to the SS7 network under one specific 199 SS7 Point Code of one specific Network Appearance. SPMCs are used to 200 sum the availability/congestion/User_Part status of an SS7 201 destination point code that is distributed in the IP domain, for the 202 purpose of supporting MTP3 management procedures at an SG. In some 203 cases, the SG itself may also be a member of the SPMC. In this case, 204 the SG availability/congestion/User_Part status must also be taken 205 into account when considering any supporting MTP3 management actions. 207 MTP - The Message Transfer Part of the SS7 protocol. 209 MTP3 - MTP Level 3, the signalling network layer of SS7 211 MTP3-User - Any protocol normally using the services of the SS7 MTP3 212 (e.g., ISUP, SCCP, TUP, etc.). 214 Network Appearance � The Network Appearance uniquely identifies an SS7 215 entity (Point Code) into an SS7 network, as presented by the SG. It is 216 used for the purposes of logically separating the signalling traffic 217 between the SG and the Application Server Processes over a common SCTP 218 association. This partitioning is necessary where an SG is logically 219 partitioned to appear as end node elements in multiple separate SS7 220 networks, in which case there is a separate network appearance for each 221 point code in the SS7 networks. It is also necessary when an SG is 222 configured as an STP hosting multiple point codes, or when configured 223 as multiple end nodes within the same network, in which case each point 224 code is a separate network appearance.between the SG and the 225 Application Server Processes over a common SCTP Association. An 226 example is where an SG is logically partitioned to appear as an element 227 in four separate national SS7 networks. A Network Appearance 228 implicitly defines the SS7 Point Code(s), Network Indicator and MTP3 229 protocol type/variant/version used within a specific SS7 network 230 partition. 232 Network Byte Order: Most significant byte first, a.k.a Big Endian. 234 Layer Management - Layer Management is a nodal function that handles 235 the inputs and outputs between the M3UA layer and a local management 236 entity. 238 Host - The computing platform that the ASP process is running on. 240 Stream - A stream refers to an SCTP stream; a uni-directional logical 241 channel established from one SCTP endpoint to another associated SCTP 242 endpoint, within which all user messages are delivered in-sequence 243 except for those submitted to the un-ordered delivery service. 245 1.3 M3UA Overview 247 1.3.1 Protocol Architecture. 249 The framework architecture that has been defined for SCN signalling 250 transport over IP [1] uses multiple components, including a common 251 signalling transport protocol and an adaptation module to support the 252 services expected by a particular SCN signalling protocol from its 253 underlying protocol layer. 255 Within the framework architecture, this document defines an MTP3-User 256 adaptation module suitable for supporting the transfer of messages of 257 any protocol layer that is identified to the MTP Level 3 layer, in SS7 258 terms, as a user part. The list of these protocol layers include, but 259 is not limited to, ISDN User Part (ISUP) [2,3,4], Signalling Connection 260 Control Part (SCCP) [5,6,7] and Telephone User Part (TUP) [8]. TCAP 261 [9,10,11] or RANAP [12] messages are transferred transparently by the 262 M3UA protocol as SCCP payload, as they are SCCP-User protocols. 264 It is recommended that M3UA use the services of the Stream Control 265 Transmission Protocol (SCTP) [13] as the underlying reliable common 266 signalling transport protocol. This is to take advantage of various 267 SCTP features such as: 269 - Explicit packet-oriented delivery (not stream-oriented), 270 - Sequenced delivery of user messages within multiple streams, 271 with an option for order-of-arrival delivery of individual 272 user messages, 273 - Optional multiplexing of user messages into SCTP datagrams, 274 - Network-level fault tolerance through support of multi-homing 275 at either or both ends of an association, 276 - Resistance to flooding and masquerade attacks, and 277 - Data segmentation to conform to discovered path MTU size. 279 Under certain scenarios, such as back-to-back connections without 280 redundancy requirements, the SCTP functions above MAY NOT be a 281 requirement and TCP can be used as the underlying common transport 282 protocol. 284 1.3.2 Services Provided by the M3UA Layer 286 The M3UA Layer at an ASP or IPSP provides the equivalent set of 287 primitives at its upper layer to the MTP3-Users as provided by the MTP 288 Level 3 to its local MTP3-Users at an SS7 SEP. In this way, the ISUP 289 and/or SCCP layer at an ASP or IPSP is unaware that the expected MTP3 290 services are offered remotely from an MTP3 Layer at an SGP, and not by 291 a local MTP3 layer. The MTP3 layer at an SGP may also be unaware that 292 its local users are actually remote user parts over M3UA. In effect, 293 the M3UA extends access to the MTP3 layer services to a remote IP-based 294 application. The M3UA layer does not itself provide the MTP3 services. 295 However, in the case where an ASP is connected to more than one SGP, 296 the 297 M3UA layer at an ASP must maintain the status of configured SS7 298 destinations and route messages according to the availability and 299 congestion status of the routes to these destinations via each SGP. 301 The M3UA layer may also be used for point-to-point signalling between 302 two IP Server Processes (IPSPs). In this case, the M3UA layer provides 303 the same set of primitives and services at its upper layer as the MTP3. 304 However, in this case the expected MTP3 services are not offered 305 remotely from an SGP. The MTP3 services are provided but the 306 procedures to support these services are a subset of the MTP3 307 procedures due to the simplified point-to-point nature of the IPSP to 308 IPSP relationship. 310 1.3.2.1 Support for the Transport of MTP3-User Messages 312 The M3UA layer provides the transport of MTP-TRANSFER primitives across 313 an established SCTP association between an SGP and an ASP or between 314 IPSPs. 316 The MTP-TRANSFER primitive information is encoded as in MTP3-User 317 messages. In this way, the SCCP and ISUP messages received from the 318 SS7 network by the SGP are not re-encoded into a different format for 319 transport between the M3UA peers. The MTP3 Service Information Octet 320 (SIO) and Routing Label (OPC, DPC, and SLS) are included, encoded as 321 expected by the MTP3 and MTP3-User protocol layer. 323 At an ASP, in the case where a destination is reachable via multiple 324 SGPs, the M3UA layer must also choose via which SGP the message is to 325 be routed or support load balancing across the SGPs, ensuring that no 326 missequencing occurs. 328 The M3UA layer does not impose a 272-octet signalling information field 329 (SIF) length limit as specified by the SS7 MTP Level 2 protocol [14] 330 [15] [16]. Larger information blocks can be accommodated directly by 331 M3UA/SCTP, without the need for an upper layer segmentation/re-assembly 332 procedure as specified in recent SCCP or ISUP versions. However, in 333 the context of an SG, the maximum 272-octet block size must be followed 334 when inter-working to a SS7 network that does not support the transfer 335 of larger information blocks to the final destination. This avoids 336 potential ISUP or SCCP fragmentation requirements at the SGPs. 337 However, if the SS7 network is provisioned to support the Broadband MTP 338 [20] to the final SS7 destination, the information block size limit may 339 be increased past 272 octets. 341 1.3.2.2 Native Management Functions 343 The M3UA layer provides management of the underlying SCTP transport 344 protocol to ensure that SGP-ASP and IPSP-IPSP transport is available to 345 the degree called for by the MTP3-User signalling applications. 347 The M3UA layer provides the capability to indicate errors associated 348 with received M3UA messages and to notify, as appropriate, local 349 management and/or the peer M3UA. 351 1.3.2.3 Inter-working with MTP3 Network Management Functions 353 At the SGP, the M3UA layer must also provide inter-working with MTP3 354 management functions to support seamless operation of the user SCN 355 signalling applications in the SS7 and IP domains. This includes: 357 - Providing an indication to MTP3-Users at an ASP that a remote 358 destination in the SS7 network is not reachable. 360 - Providing an indication to MTP3-Users at an ASP that a remote 361 destination in the SS7 network is now reachable. 363 - Providing an indication to MTP3-Users at an ASP that messages to a 364 remote destination in the SS7 network are experiencing SS7 365 congestion. 367 - Providing an indication to the M3UA layer at an ASP that the routes 368 to a remote destination in the SS7 network are restricted. 370 - Providing an indication to MTP3-Users at an ASP that a remote MTP3- 371 User peer is unavailable. 373 The M3UA layer at an ASP may initiate an audit of the availability, the 374 restricted or the congested state of remote SS7 destinations. This 375 information is requested from the M3UA layer at the SGP. 377 The M3UA layer at an ASP may also indicate to the SG that the M3UA 378 layer itself or the ASP or the ASP's Host is congested. 380 1.3.2.4 Support for the Management of SCTP Associations between the SGP 381 and ASPs. 383 The M3UA layer at the SGP maintains the availability state of all 384 configured remote ASPs, in order to manage the SCTP Associations and 385 the traffic between the M3UA peers. As well, the active/inactive and 386 congestion state of remote ASPs is maintained. 388 The M3UA layer MAY be instructed by local management to establish an 389 SCTP association to a peer M3UA node. This can be achieved using the 390 M-SCTP_ESTABLISH primitives to request, indicate and confirm the 391 establishment of an SCTP association with a peer M3UA node. In order 392 to avoid redundant SCTP associations between two M3UA peers, one side 393 (client) SHOULD be designated to establish the SCTP association, or 394 M3UA configuration knowledge maintained to detect redundant 395 associations (e.g., via knowledge of the expected local and remote SCTP 396 endpoint addresses). 398 Local management MAY request from the M3UA layer the status of the 399 underlying SCTP associations using the M-SCTP_STATUS request and 400 confirm primitives. Also, the M3UA MAY autonomously inform local 401 management of the reason for the release of an SCTP association, 402 determined either locally within the M3UA layer or by a primitive from 403 the SCTP. 405 Also the M3UA layer MAY inform the local management of the change in 406 status of an ASP or AS. This may be achieved using the M-ASP_request 407 or M-AS_STATUS request primitives. 409 1.3.2.5 Support for the Management of Connections to Multiple SGPs 411 As shown in Figure 1 an ASP may be connected to multiple SGPs. In such 412 a case a particular SS7 destination may be reachable via more than one 413 SGP, i.e., via more than one route. As MTP3 users only maintain status 414 on a destination and not on a route basis, the M3UA layer must maintain 415 the status (availability, restriction, and/or congestion of route to 416 destination) of the individual routes, derive the overall availability 417 or congestion status of the destination from the status of the 418 individual routes, and inform the MTP3 users of this derived status 419 whenever it changes. 421 1.3.3 Signalling Network Architecture 423 A Signalling Gateway is used to support the transport of MTP3-User 424 signalling traffic received from the SS7 network to multiple 425 distributed ASPs (e.g., MGCs and IP Databases). Clearly, the M3UA 426 protocol is not designed to meet the performance and reliability 427 requirements for such transport by itself. However, the conjunction of 428 distributed architecture and redundant networks does allow for a 429 sufficiently reliable transport of signalling traffic over IP. The 430 M3UA protocol is flexible enough to allow its operation and management 431 in a variety of physical configurations, enabling Network Operators to 432 meet their performance and reliability requirements. 434 To meet the stringent SS7 signalling reliability and performance 435 requirements for carrier grade networks, Network Operators SHOULD 436 ensure that no single point of failure is present in the end-to-end 437 network architecture between an SS7 node and an IP-based application. 438 This can typically be achieved through the use of redundant SGPs or 439 SGs, redundant hosts, and the provision of redundant QOS-bounded IP 440 network paths for SCTP Associations between SCTP End Points. Obviously, 441 the reliability of the SG, the MGC and other IP-based functional 442 elements also needs to be taken into account. The distribution of ASPs 443 and SGPs within the available Hosts SHOULD also be considered. As an 444 example, for a particular Application Server, the related ASPs SHOULD 445 be distributed over at least two Hosts. 447 One example of a physical network architecture relevant to SS7 carrier- 448 grade operation in the IP network domain is shown in Figure 1 below: 450 SG MGC 452 Host#1 ************** ************** Host#3 453 = * ********__*__________________________*__******** * = 454 * * SGP1 *__*_____ _______________*__* ASP1 * * MGC1 455 * ******** * \ / * ******** * 456 * ********__*______\__/________________*__******** * 457 * * SGP2 *__*_______\/______ _____*__* ASP2 * * 458 * ******** * /\ | | * ******** * 459 * : * / \ | | * : * 460 * ******** * / \ | | * ******** * 461 * * SGPn * * | | | | * * ASPn * * 462 * ******** * | | | | * ******** * 463 ************** | | | | ************** 464 | | \ / 465 Host#2 ************** | | \ / ************** Host#4 466 = * ********__*_____| |______\/_______*__******** * = 467 * * SGP1 *__*_________________/\_______*__* ASP1 * * MGC2 468 * ******** * / \ * ******** * 469 * ********__*_______________/ \_____*__******** * 470 * * SGP2 *__*__________________________*__* ASP2 * * 471 * ******** * * ******** * 472 * : * SCTP Associations * : * 473 * ******** * * ******** * 474 * * SGPn * * * * ASPn * * 475 * ******** * * ******** * 476 ************** ************** 478 Figure 1 - Physical Model 480 In this model, each host has many application processes. In the case 481 of the MGC, an ASP may provide service to one or more Application 482 Servers, and is identified as an SCTP end point. A pair of signalling 483 gateway processes may represent, as an example, a single Signalling 484 Gateway, serving a signalling point management cluster. 486 This example model can also be applied to IPSP-IPSP signalling. In 487 this case, each IPSP would have its services distributed across 2 hosts 488 or more, and may have multiple server processes on each host. 490 In the example above, each signalling process (SGP, ASP or IPSP) is the 491 end point to more than one SCTP association, leading to many other 492 signalling processes. To support this, a signalling process must be 493 able to support distribution of M3UA messages to many simultaneous 494 active associations. This message distribution function is based on 495 the status of provisioned routing keys, the availability of signalling 496 points in the SS7 network, and the redundancy model (active-standby, 497 load-sharing, n+k) of the remote signalling processes. 499 For carrier grade networks, the failure or isolation of a particular 500 signalling process SHOULD NOT cause stable calls or transactions to be 501 lost. This implies that signalling processes need, in some cases, to 502 share the call/transaction state or be able to pass the call state 503 information between each other. In the case of ASPs performing call 504 processing, coordination may also be required with the related Media 505 Gateway to transfer the MGC control for a particular trunk termination. 506 However, this sharing or communication of call/transaction state 507 information is outside the scope of this document. 509 This model serves as an example. M3UA imposes no restrictions as to 510 the exact layout of the network elements, the message distribution 511 algorithms and the distribution of the signalling processes. Instead, 512 it provides a framework and a set of messages that allow for a flexible 513 and scalable signalling network architecture, aiming to provide 514 reliability and performance. 516 1.4 Functional Areas 518 1.4.1 Signalling Point Code Representation 520 For example, within an SS7 network, a Signalling Gateway might be 521 charged with representing a set of nodes in the IP domain into the SS7 522 network for routing purposes. The SG itself, as a signalling point in 523 the SS7 network, might also be addressable with an SS7 Point Code for 524 MTP3 Management purposes. The SG Point Code might also used for 525 addressing any local MTP3-Users at the SG such as an SG-resident SCCP 526 function. 528 An SG may be logically partitioned to operate in multiple SS7 network 529 appearances. In such a case, the SG must be addressable with a Point 530 Code in each network appearance, and represents a set of nodes in the 531 IP domain into each SS7 network. Alias Point Codes [15] may also be 532 used within an SG network appearance. 534 Where an SG contains more than one SGP, the MTP3 routeset, SPMC and 535 remote AS/ASP states of each SGP SHOULD be coordinated across all the 536 SGPs. Re-routing of traffic between the SGPs SHOULD also be supported 538 The M3UA places no restrictions on the SS7 Point Code representation of 539 an AS. Application Servers can be represented under the same Point 540 Code of the SG, their own individual Point Codes or grouped with other 541 Application Servers for Point Code preservation purposes. A single 542 Point Code may be used to represent the SG and all the Application 543 Servers together, if desired. 545 If an ASP or group of ASPs is available to the SS7 network via more 546 than one SG, each with its own Point Code, the ASP(s) should be 547 represented by a Point Code that is separate from any SG Point Code. 548 This allows these SGs to be viewed from the SS7 network as "STPs", each 549 having an ongoing "route" to the same ASP(s). Under failure conditions 550 where the ASP(s) become(s) unavailable from one of the SGs, this 551 approach enables MTP3 route management messaging between the SG and SS7 552 network, allowing simple SS7 re-routing through an alternate SG without 553 changing the Destination Point Code Address of SS7 traffic to the 554 ASP(s). 556 Where an AS can be reached via more than one SGP it is equally 557 important that the corresponding Routing Keys in the involved SGPs are 558 identical. (Note: It is possible for the SGP Routing Key configuration 559 data to be temporarily out-of-synch during configuration updates). 561 +--------+ 562 | | 563 +------------+ SG 1 +--------------+ 564 +-------+ | SS7 links | "STP" | IP network | ---- 565 | SEP +---+ +--------+ +---/ \ 566 | or | * | ASPs | 567 | STP +---+ +--------+ +---\ / 568 +-------+ | | | | ---- 569 +------------+ SG 2 +--------------+ 570 | "STP" | 571 +--------+ 573 * Note:. SG-to �SG communication is recommended for carrier grade 574 networks, using an MTP3 linkset or an equivalent, to allow re-routing 575 between the SGs in the event of route failures. Where SGPs are used, 576 inter-SGP communication is recommended. Inter-SGP protocol is outside 577 of the scope of this document. 579 The following example shows a signalling gateway partitioned into two 580 network appearances. 582 SG 583 +-------+ +---------------+ 584 | SEP +--------------| SS7 Ntwk |M3UA| ---- 585 +-------+ SS7 links | "A" | | / \ 586 |__________| +-----------+ ASPs | 587 | | | \ / 588 +-------+ | SS7 Ntwk | | ---- 589 | SEP +--------------+ "B" | | 590 +-------+ +---------------+ 592 1.4.2 Routing Contexts and Routing Keys 594 1.4.2.1 Overview 596 The distribution of SS7 messages between the SGP and the Application 597 Servers is determined by the Routing Keys and their associated Routing 598 Contexts. A Routing Key is essentially a set of SS7 parameters used to 599 filter SS7 messages, whereas the Routing Context parameter is a 4-byte 600 value (integer) that is associated to that Routing Key in a 1:1 601 relationship. The Routing Context therefore can be viewed as an index 602 into a sending node's Message Distribution Table containing the Routing 603 Key entries. 605 Possible SS7 address/routing information that comprise a Routing Key 606 entry includes, for example, the OPC, DPC, SIO found in the MTP3 607 routing label, or MTP3-User specific fields such as the ISUP CIC, SCCP 608 subsystem number, or TCAP transaction ID. Some example Routing Keys 609 are: the DPC alone, the DPC/OPC combination, the DPC/OPC/CIC 610 combination, or the DPC/SSN combination. The particular information 611 used to define an M3UA Routing Key is application and network 612 dependent, and none of the above examples are mandated. 614 An Application Server Process may be configured to process signalling 615 traffic related to more than one Application Server, over a single SCTP 616 Association. In ASP Active and ASP Inactive management messages, the 617 signalling traffic to be started or stopped is discriminated by the 618 Routing Context parameter. At an ASP, the Routing Context parameter 619 uniquely identifies the range of signalling traffic associated with 620 each Application Server that the ASP is 621 configured to receive. 623 1.4.2.2 Routing Key Limitations 625 Routing Keys SHOULD be unique in the sense that each received SS7 626 signalling message SHOULD have a single routing result to an 627 Application Server. It is not necessary for the parameter range values 628 within a particular Routing Key to be contiguous. For example, an AS 629 could be configured to support call processing for multiple ranges of 630 PSTN trunks that are not represented by contiguous CIC values. 632 1.4.2.3 Managing Routing Contexts and Routing Keys 634 There are two ways to provision a Routing Key at an SGP. A 635 Routing Key may be configured statically using an implementation 636 dependent management interface, or dynamically using the M3UA Routing 637 Key registration procedure. A Routing Key may also be configured using 638 the M3UA dynamic registration/deregistration procedures defined in this 639 document. An M3UA element must implement at least one method of 640 Routing Key provisioning. 642 When using a management interface to configure Routing Keys, the 643 message distribution function within the SGP is not limited to the set 644 of parameters defined in this document. Other implementation dependent 645 distribution algorithms may be used. 647 1.4.2.4 Message Distribution at the SGP 649 In order to direct messages received from the SS7 MTP3 network to the 650 appropriate IP destination, the SGP must perform a message distribution 651 function using information from the received MTP3-User message. 653 To support this message distribution, the SGP must maintain the 654 equivalent of a network address translation table, mapping incoming SS7 655 message information to an Application Server for a particular 656 application and range of traffic. This is accomplished by comparing 657 elements of the incoming SS7 message to currently defined Routing Keys 658 in the SGP. These Routing Keys in turn make reference to an 659 Application Server that is enabled by one or more ASPs. These ASPs 660 provide dynamic status information on their availability, traffic 661 handling capability and congestion to the SGP using various management 662 messages defined in the M3UA protocol. 664 The list of ASPs in an AS is assumed to be dynamic, taking into account 665 the availability, traffic handling capability and congestion status of 666 the individual ASPs in the list, as well as configuration changes and 667 possible fail-over mechanisms. 669 Normally, one or more ASPs are active in the AS (i.e., currently 670 processing traffic) but in certain failure and transition cases it is 671 possible that there may be no active ASP available. Both load-sharing 672 and backup scenarios are supported. 674 When there is no matching Routing Key entry for an incoming SS7 675 message, a default treatment SHOULD be specified. Possible solutions 676 are to provide a default Application Server at the SGP that directs all 677 unallocated traffic to a (set of) default ASP(s), or to drop the 678 message and provide a notification to layer management. The treatment 679 of unallocated traffic is implementation dependent. 681 1.4.2.5 Message Distribution at the ASP 683 In order to direct messages to the SS7 network, the ASP must also 684 perform a message distribution function in order to choose the proper 685 SGP for a given message. This is accomplished by observing the 686 Destination Point Code (and possibly other elements of the outgoing 687 message such as the SLS value).Where more than one route (or SGP) is 688 possible for routing to the SS7 network, the ASP SHOULD maintain a 689 dynamic table of available SGP routes for the SS7 destinations, taking 690 into account the SS7 destination availability/restricted/congestion 691 status received from the SGP(s), the availability status of the 692 individual SGPs and configuration changes and fail-over mechanisms. 693 There is, however, no M3UA messaging to manage the status of an SGP 694 (e.g., SGP-Up/Down/Active/Inactive messaging). Whenever an SCTP 695 association to an SGP exists, the SGP is assumed to be ready for the 696 purposes of responding to M3UA ASPSM messages. 698 Every SGP of one SG ASP regarding one AS provides identical SS7 699 connectivity to this ASP. 701 1.4.3 SS7 and M3UA Interworking 703 In the case of SS7 and M3UA inter-working, the M3UA adaptation layer is 704 designed to provide an extension of the MTP3 defined user primitives. 706 1.4.3.1 Signalling Gateway SS7 Layers 708 The SG is responsible for terminating MTP Level 3 of the SS7 protocol, 709 and offering an IP-based extension to its users. 711 >From an SS7 perspective, it is expected that the Signalling Gateway 712 transmits and receives SS7 Message Signalling Units (MSUs) to and 713 from the PSTN over a standard SS7 network interface, using the SS7 714 Message Transfer Part (MTP) [14,15,16] to provide reliable transport of 715 the messages. 717 As a standard SS7 network interface, the use of MTP Level 2 signalling 718 links is not the only possibility. ATM-based High Speed Links can also 719 be used with the services of the Signalling ATM Adaptation Layer (SAAL) 720 [17,18]. 722 Note: It is also possible for IP-based interfaces to be present, using 723 the services of the MTP2-User Adaptation Layer (M2UA) [23] or M2PA []. 724 These may be terminated at a Signalling Transfer Point (STP) or 725 Signalling End Point (SEP). Using the services of MTP3, the SG may be 726 capable of communicating with remote SS7 SEPs in a quasi-associated 727 fashion, where STPs may be present in the SS7 path between the SEP and 728 the SG. 730 1.4.3.2 SS7 and M3UA Inter-Working at the SG 732 The SGP provides a functional inter-working of transport functions 733 between the SS7 network and the IP network by also supporting the M3UA 734 adaptation layer. It allows the transfer of MTP3-User signalling 735 messages to and from an IP-based Application Server Process where the 736 peer MTP3-User protocol layer exists. 738 The Signalling Gateway must maintain knowledge of relevant SS7 node and 739 Signalling Point Management Cluster (SPMC) status in their respective 740 domains in order to perform a seamless inter-working of the IP-based 741 signalling and the SS7 domains. For example, SG knowledge of the 742 availability and/or congestion status of the SPMC and SS7 nodes must be 743 maintained and disseminated in the respective networks, in order to 744 ensure that end-to-end operation is transparent to the communicating 745 SCN protocol peers at the SS7 node and ASP. Where more than one SGP 746 constitutes an SG, the knowledge of the SGPs must be coordinated into 747 an overall SG view. 749 For SS7 user part management, it is required that the MTP3-User 750 protocols at ASPs receive indications of SS7 signalling point 751 availability, SS7 network congestion, and remote User Part 752 unavailability as would be expected in an SS7 SEP node. To accomplish 753 this, the MTP-PAUSE, MTP-RESUME and MTP-STATUS indication primitives 754 received at the MTP3 upper layer interface at the SG need to be 755 propagated to the remote MTP3-User lower layer interface at the ASP. 756 (These indication primitives are also made available to any existing 757 local MTP3-Users at the SG, if present.) 759 MTP3 management messages (such as TFPs or TFAs received from the SS7 760 network) MUST NOT be encapsulated as Data message Payload Data and sent 761 either from SG to ASP or from ASP to SG. The SG MUST terminate these 762 messages and generate M3UA messages as appropriate. 764 1.4.3.3 Application Server 766 A cluster of application servers is responsible for providing the 767 overall support for one or more SS7 upper layers. From an SS7 768 standpoint, a Signalling Point Management Cluster (SPMC) provides 769 complete support for the upper layer service for a given point code. 770 As an example, an SPMC providing MGC capabilities must provide complete 771 support for ISUP (and any other MTP3 user located at the point code of 772 the SPMC) for a given point code, according to the local SS7 network 773 specifications. 775 This measure is necessary to allow the SG to accurately represent the 776 signalling point on the local SS7 network. 778 In the case where an ASP is connected to more than one SGP, the M3UA 779 layer must maintain the status of configured SS7 destinations and route 780 messages according to availability/congestion/restricted status of the 781 routes to these SS7 destinations. 783 1.4.3.4 IPSP Considerations 785 Since IPSPs use M3UA in a point-to-point fashion, there is no concept 786 of routing of messages beyond the remote end. Therefore, SS7 and M3UA 787 inter-working is not necessary for this model. 789 1.4.4 Redundancy Models 791 The network address translation and mapping function of the M3UA layer 792 supports signalling process fail-over functions in order to support a 793 high availability of call and transaction processing capability. 795 1.4.4.1 Application Server Redundancy 797 All MTP3-User messages (e.g., ISUP, SCCP) incoming to an SG from the 798 SS7 network are assigned to a unique Application Server, based on the 799 information in the message and the provisioned Routing Keys. 801 The Application Server is, in practical terms, a list of all ASPs 802 configured to process a range of MTP3-User traffic defined by one 803 Routing Key. One or more ASPs in the list are normally active (i.e., 804 handling traffic) while any others may be unavailable or inactive, to 805 be possibly used in the event of failure or unavailability of the 806 active ASP(s). 808 The fail-over model supports an "n+k" redundancy model, where "n" ASPs 809 is the minimum number of redundant ASPs required to handle traffic and 810 "k" ASPs are available to take over for a failed or unavailable ASP. A 811 "1+1" active/back-up redundancy is a subset of this model. A simplex 812 "1+0" model is also supported as a subset, with no ASP redundancy. 814 At the SGP, an Application Server list contains active and inactive 815 ASPs to support ASP load-sharing and fail-over procedures. The list of 816 ASPs within a logical Application Server is kept updated in the SGP to 817 reflect the active Application Server Process(es). 819 To avoid a single point of failure, it is recommended that a minimum of 820 two ASPs be in the list, resident in separate hosts and therefore 821 available over different SCTP Associations. For example, in the 822 network shown in Figure 1, all messages to DPC x could be sent to ASP1 823 in Host3 or ASP1 in Host4. The AS list at SGP1 in Host 1 might look 824 like the following: 826 Routing Key {DPC=x) - "Application Server #1" 827 ASP1/Host3 - State = Active 828 ASP1/Host3 - State = Inactive 830 In this "1+1" redundancy case, ASP1 in Host3 would be sent any incoming 831 message with DPC=x. ASP1 in Host4 would normally be brought to the 832 "active" state upon failure of, or loss of connectivity to, ASP1/Host1. 834 The AS List at SGP1 in Host1 might also be set up in load-share mode: 836 Routing Key {DPC=x) - "Application Server #1" 837 ASP1/Host3 - State = Active 838 ASP1/Host4 - State = Active 840 In this case, both the ASPs would be sent a portion of the traffic. 841 For example the two ASPs could together form a database, where incoming 842 queries may be sent to any active ASP. 844 Care must be exercised by a Network Operator in the selection of the 845 routing information to be used as the Routing Key for a particular AS. 847 For example, where Application Servers are defined using ranges of ISUP 848 CIC values, the Operator is implicitly splitting up control of the 849 related circuit groups. Some CIC value range assignments may interfere 850 with ISUP circuit group management procedures. 852 In the process of fail-over, it is recommended that in the case of ASPs 853 supporting call processing, stable calls do not fail. It is possible 854 that calls in "transition" MAY fail, although measures of communication 855 between the ASPs involved can be used to mitigate this. For example, 856 the two ASPs MAY share call state via shared memory, or MAY use an ASP 857 to ASP protocol to pass call state information. Any ASP-to-ASP 858 protocol to support this function is outside the scope of this 859 document. 861 1.4.4.2 Signalling Gateway Redundancy 863 Signalling Gateways MAY also be distributed over multiple hosts. Much 864 like the AS model, SGs may comprise one or more SG Processes (SGPs), 865 distributed over one or more hosts, using an active/back-up or a load- 866 sharing model. Also, every SGP within an SG communicating with an ASP 867 provides identical SS7 connectivity to this ASP. Should an SGP lose all 868 or partial SS7 connectivity and other SGPs exist, the SGP SHOULD 869 terminate the SCTP associations to the concerned ASPs. 871 It is therefore possible for an ASP to route signalling messages 872 destined to the SS7 network using more than one SGP. In this model, a 873 Signalling Gateway is deployed as a cluster of hosts acting as a single 874 SG. A primary/back-up redundancy model is possible, where the 875 unavailability of the SCTP association to a primary SGP could be used 876 to reroute affected traffic to an alternate SGP. A load-sharing model 877 is possible, where the signalling messages are load-shared between 878 multiple SGPs. The distribution of the MTP3-user messages over the 879 SGPs should be done in such a way to minimize message mis-sequencing, 880 as required by the SS7 User Parts. 882 It may also be possible for an ASP to use more than one SG to access a 883 specific SS7 end point, in a model that resembles an SS7 STP mated 884 pair. Typically, SS7 STPs are deployed in mated pairs, with traffic 885 load-shared between them. Other models are also possible, subject to 886 the limitations of the local SS7 network provisioning guidelines. 888 >From the perspective of the M3UA layer at an ASP, a particular SG is 889 capable of transferring traffic to an SS7 destination if an SCTP 890 association with at least one SGP of the SG is established, the SGP has 891 returned an acknowledgement to the ASP to indicate that the ASP is 892 actively handling traffic for that destination, and the SGP has not 893 indicated that the destination is inaccessible. When an ASP is 894 configured to use multiple SGPs for transferring traffic to the SS7 895 network, the ASP must maintain knowledge of the current capability of 896 the SGPs to handle traffic to destinations of interest. This 897 information is crucial to the overall reliability of the service, for 898 both active/back-up and load-sharing model, in the event of failures, 899 recovery and maintenance activities. The ASP M3UA may also use this 900 information for congestion avoidance purposes. The distribution of the 901 MTP3-user messages over the SGPs should be done in such a way to 902 minimize message mis-sequencing, as required by the SS7 User Parts. 904 1.4.5 Flow Control 905 Local Management at an ASP may wish to stop traffic across an SCTP 906 association in order to temporarily remove the association from service 907 or to perform testing and maintenance activity. The function could 908 optionally be used to control the start of traffic on to a newly 909 available SCTP association. 911 1.4.6 Congestion Management 913 The M3UA layer is informed of local and IP network congestion by means 914 of an implementation-dependent function (e.g., an implementation- 915 dependent indication from the SCTP of IP network congestion). 917 At an ASP or IPSP, the M3UA layer indicates congestion to local MTP3- 918 Users by means of an MTP-STATUS primitive, as per current MTP3 919 procedures, to invoke appropriate upper layer responses. 921 When an SG determines that the transport of SS7 messages to a 922 Signalling Point Management Cluster (SPMC) is encountering congestion, 923 the SG MAY trigger SS7 MTP3 Transfer Controlled management messages 924 to originating SS7 nodes, per the congestion procedures of the relevant 925 MTP3 standard. The triggering of SS7 MTP3 Management messages from an 926 SG is an implementation-dependent function. 928 The M3UA layer at an ASP or IPSP should indicate local congestion to an 929 M3UA peer with an SCON message. When an SG receives a congestion 930 message (SCON) from an ASP, and the SG determines that an SPMC is now 931 encountering congestion, it MAY trigger SS7 MTP3 Transfer Controlled 932 management messages to concerned SS7 destinations according to 933 congestion procedures of the relevant MTP3 standard. 935 1.4.7 SCTP Stream Mapping. 937 The M3UA layer at both the SGP and ASP also supports the assignment of 938 signalling traffic into streams within an SCTP association. Traffic 939 that requires sequencing must be assigned to the same stream. To 940 accomplish this, MTP3-User traffic may be assigned to individual 941 streams based on, for example, the SLS value in the MTP3 Routing Label 942 or the ISUP CIC assignment, subject of course to the maximum number of 943 streams supported by the underlying SCTP association. 945 The use of SCTP streams within M3UA is recommended in order to minimize 946 transmission and buffering delays, therefore improving the overall 947 performance and reliability of the signalling elements. The 948 distribution of the MTP3 user messages over the various streams should 949 be done in such a way to minimize message mis-sequencing, as required 950 by the SS7 User Parts. 952 1.4.8 Client/Server Model 954 It is recommended that the SGP and ASP be able to support both client and server 955 operation. The peer endpoints using M3UA SHOULD be configured so that one always 956 takes on the role of client and the other the role of server for initiating SCTP 957 associations. The default orientation would be for the SGP to take on the role 958 of server while the ASP is the client. In this case, ASPs SHOULD initiate the 959 SCTP association to the SGP 961 In the case of IPSP to IPSP communication, the peer endpoints using 962 M3UA SHOULD be configured so that one always takes on the role of 963 client and the other the role of server for initiating SCTP 964 associations. 966 The SCTP Registered User Port Number Assignment for M3UA is 2905. 968 1.5 Sample Configurations 970 1.5.1 Example 1: ISUP Message Transport 972 ******** SS7 ***************** IP ******** 973 * SEP *---------* SGP *--------* ASP * 974 ******** ***************** ******** 976 +------+ +------+ 977 | ISUP | (NIF) | ISUP | 978 +------+ +------+-+------+ +------+ 979 | MTP3 | | MTP3 | | M3UA | | M3UA | 980 +------| +------+ +------+ +------+ 981 | MTP2 | | MTP2 | | SCTP | | SCTP | 982 +------+ +------+ +------+ +------+ 983 | L1 | | L1 | | IP | | IP | 984 +------+ +------+ +------+ +------+ 985 |_______________| |______________| 987 SEP - SS7 Signalling End Point 988 SCTP - Stream Control Transmission Protocol 989 NIF - Nodal Inter-working Function 991 In this example, the SGP provides an implementation-dependent nodal 992 inter-working function (NIF) that allows the MGC to exchange SS7 993 signalling messages with the SS7-based SEP. The NIF within the SGP 994 serves as the interface within the SGP between the MTP3 and M3UA. This 995 nodal inter-working function has no visible peer protocol with either 996 the MGC or SEP. It also provides network status information to one or 997 both sides of the network. 999 For internal SGP modeling purposes, at the NIF level, SS7 signalling 1000 messages that are destined to the MGC are received as MTP-TRANSFER 1001 indication primitives from the MTP Level 3 upper layer interface, 1002 translated to MTP-TRANSFER request primitives, and sent to the local 1003 M3UA-resident message distribution function for ongoing routing to the 1004 final IP destination. Messages received from the local M3UA network 1005 address translation and mapping function as MTP-TRANSFER indication 1006 primitives are sent to the MTP Level 3 upper layer interface as MTP- 1007 TRANSFER request primitives for on-going MTP Level 3 routing to an SS7 1008 SEP. For the purposes of providing SS7 network status information the 1009 NIF also delivers MTP-PAUSE, MTP-RESUME and MTP-STATUS indication 1010 primitives received from the MTP Level 3 upper layer interface to the 1011 local M3UA-resident management function. In addition, as an 1012 implementation and network option, restricted destinations are 1013 communicated from MTP network management to the local M3UA-resident 1014 management function. 1016 1.5.2 Example 2: SCCP Transport between IPSPs 1018 ******** IP ******** 1019 * IPSP * * IPSP * 1020 ******** ******** 1022 +------+ +------+ 1023 |SCCP- | |SCCP- | 1024 | User | | User | 1025 +------+ +------+ 1026 | SCCP | | SCCP | 1027 +------+ +------+ 1028 | M3UA | | M3UA | 1029 +------+ +------+ 1030 | SCTP | | SCTP | 1031 +------+ +------+ 1032 | IP | | IP | 1033 +------+ +------+ 1034 |________________| 1036 This example shows an architecture where no Signalling Gateway is used. 1037 In this example, SCCP messages are exchanged directly between two IP- 1038 resident IPSPs with resident SCCP-User protocol instances, such as 1039 RANAP or TCAP. SS7 network inter-working is not required, therefore 1040 there is no MTP3 network management status information for the SCCP and 1041 SCCP-User protocols to consider. Any MTP-PAUSE, MTP-RESUME or MTP- 1042 STATUS indications from the M3UA layer to the SCCP layer should 1043 consider the status of the SCTP Association and underlying IP network 1044 and any congestion information received from the remote site. 1046 1.5.3 Example 3: SGP Resident SCCP Layer, with Remote ASP 1048 ******** SS7 ***************** IP ******** 1049 * SEP *---------* *--------* * 1050 * or * * SGP * * ASP * 1051 * STP * * * * * 1052 ******** ***************** ******** 1054 +------+ +---------------+ +------+ 1055 | SCCP-| | SCCP | | SCCP-| 1056 | User | +---------------+ | User | 1057 +------+ | _____ | +------+ 1058 | SCCP | | | | | | SCCP | 1059 +------+ +------+-+------+ +------+ 1060 | MTP3 | | MTP3 | | M3UA | | M3UA | 1061 +------| +------+ +------+ +------+ 1062 | MTP2 | | MTP2 | | SCTP | | SCTP | 1063 +------+ +------+ +------+ +------+ 1064 | L1 | | L1 | | IP | | IP | 1065 +------+ +------+ +------+ +------+ 1066 |_______________| |______________| 1068 STP - SS7 Signalling Transfer Point 1070 In this example, the SGP contains an instance of the SS7 SCCP protocol 1071 layer that may, for example, perform the SCCP Global Title Translation 1072 (GTT) function for messages logically addressed to the SG SCCP. If the 1073 result of a GTT for an SCCP message yields an SS7 DPC or DPC/SSN 1074 address of an SCCP peer located in the IP domain, the resulting MTP- 1075 TRANSFER request primitive is sent to the local M3UA-resident network 1076 address translation and mapping function for ongoing routing to the 1077 final IP destination. 1079 Similarly, the SCCP instance in an SGP can perform the SCCP GTT service 1080 for messages logically addressed to it from SCCP peers in the IP 1081 domain. In this case, MTP-TRANSFER indication primitives are sent from 1082 the local M3UA-resident network address translation and mapping 1083 function to the SCCP for GTT. If the result of the GTT yields the 1084 address of an SCCP peer in the SS7 network then the resulting MTP- 1085 TRANSFER request primitive is given to the MTP3 for delivery to an SS7- 1086 resident node. 1088 It is possible that the above SCCP GTT at the SGP could yield the 1089 address of an SCCP peer in the IP domain and the resulting MTP-TRANSFER 1090 request primitive would be sent back to the M3UA layer for delivery to 1091 an IP destination. 1093 For internal SGP modeling purposes, this may be accomplished with the 1094 use of an implementation-dependent nodal inter-working function within 1095 the SGP that effectively sits below the SCCP and routes MTP-TRANSFER 1096 request/indication messages to/from both the MTP3 and the M3UA layer, 1097 based on the SS7 DPC or DPC/SSN address information. This nodal inter- 1098 working function has no visible peer protocol with either the ASP or 1099 SEP. 1101 Note that the services and interface provided by the M3UA layer are the 1102 same as in Example 1 and the functions taking place in the SCCP entity 1103 are transparent to the M3UA layer. The SCCP protocol functions are not 1104 reproduced in the M3UA protocol. 1106 1.6 Definition of M3UA Boundaries 1108 1.6.1 Definition of the Boundary between M3UA and an MTP3-User. 1110 >From ITU Q.701 [14]: 1112 MTP-TRANSFER request 1113 MTP-TRANSFER indication 1114 MTP-PAUSE indication 1115 MTP-RESUME indication 1116 MTP-STATUS indication 1118 1.6.2 Definition of the Boundary between M3UA and SCTP 1120 An example of the upper layer primitives provided by the SCTP are 1121 provided in Reference [13] Section 10. 1123 1.6.3 Definition of the Boundary between M3UA and Layer Management 1125 M-SCTP_ESTABLISH request 1126 Direction: LM -> M3UA 1127 Purpose: LM requests ASP to establish an SCTP association with its 1128 peer. 1130 M-STCP_ESTABLISH confirm 1131 Direction: M3UA -> LM 1132 Purpose: ASP confirms to LM that it has established an SCTP 1133 association with its peer. 1135 M-SCTP_ESTABLISH indication 1136 Direction: M3UA -> LM 1137 Purpose: M3UA informs LM that a remote ASP has established an SCTP 1138 association. 1140 M-SCTP_RELEASE request 1141 Direction: LM -> M3UA 1142 Purpose: LM requests ASP to release an SCTP association with its 1143 peer. 1145 M-SCTP_RELEASE confirm 1146 Direction: M3UA -> LM 1147 Purpose: ASP confirms to LM that it has released SCTP association 1148 with its peer. 1150 M-SCTP_RELEASE indication 1151 Direction: M3UA -> LM 1152 Purpose: M3UA informs LM that a remote ASP has released an SCTP 1153 Association or the SCTP association has failed. 1155 M-SCTP_STATUS request 1156 Direction: LM -> M3UA 1157 Purpose: LM requests M3UA to report the status of an SCTP 1158 association. 1160 M-SCTP_STATUS confirm 1161 Direction: M3UA -> LM 1162 Purpose: M3UA responds with the status of an SCTP association. 1164 M-SCTP STATUS indication 1165 Direction: M3UA -> LM 1166 Purpose: M3UA reports the status of an SCTP association. 1168 M-ASP_STATUS request 1169 Direction: LM -> M3UA 1170 Purpose: LM requests M3UA to report the status of a local or remote 1171 ASP. 1173 M-ASP_STATUS confirm 1174 Direction: M3UA -> LM 1175 Purpose: M3UA reports status of local or remote ASP. 1177 M-AS_STATUS request 1178 Direction: LM -> M3UA 1179 Purpose: LM requests M3UA to report the status of an AS. 1181 M-AS_STATUS confirm 1182 Direction: M3UA -> LM 1183 Purpose: M3UA reports the status of an AS. 1185 M-NOTIFY indication 1186 Direction: M3UA -> LM 1187 Purpose: M3UA reports that it has received a Notify message 1188 from its peer. 1190 M-ERROR indication 1191 Direction: M3UA -> LM 1192 Purpose: M3UA reports that it has received an Error message from 1193 its peer or that a local operation has been unsuccessful. 1195 M-ASP_UP request 1196 Direction: LM -> M3UA 1197 Purpose: LM requests ASP to start its operation and send an ASP Up 1198 message to its peer. 1199 M-ASP_UP confirm 1200 Direction: M3UA -> LM 1201 Purpose: ASP reports that is has received an ASP UP Ack message from 1202 its peer. 1204 M-ASP_UP indication 1205 Direction: M3UA -> LM 1206 Purpose: M3UA reports it has successfully processed an incoming ASP 1207 Up message from its peer. 1209 M-ASP_DOWN request 1210 Direction: LM -> M3UA 1211 Purpose: LM requests ASP to stop its operation and send an ASP-Down 1212 message to its peer. 1214 M-ASP_DOWN confirm 1215 Direction: M3UA -> LM 1216 Purpose: ASP reports that is has received an ASP Down 1217 Ack message from its peer. 1219 M-ASP_DOWN indication 1220 Direction: M3UA -> LM 1221 Purpose: M3UA reports it has successfully processed an incoming ASP 1222 Down message from its peer, or the SCTP association has 1223 been lost/reset. 1225 M-ASP_ACTIVE request 1226 Direction: LM -> M3UA 1227 Purpose: LM requests ASP to send an ASP Active message to its peer. 1229 M-ASP_ACTIVE confirm 1230 Direction: M3UA -> LM 1231 Purpose: ASP reports that is has received an ASP Active 1232 Ack message from its peer. 1234 M-ASP_ACTIVE indication 1235 Direction: M3UA -> LM 1236 Purpose: M3UA reports it has successfully processed an incoming ASP 1237 Active message from its peer. 1239 M-ASP_INACTIVE request 1240 Direction: LM -> M3UA 1241 Purpose: LM requests ASP to send an ASP Inactive message to its 1242 peer. 1244 M-ASP_INACTIVE confirm 1245 Direction: LM -> M3UA 1246 Purpose: ASP reports that is has received an ASP Inactive 1247 Ack message from its peer. 1249 M-ASP_INACTIVE indication 1250 Direction: M3UA -> LM 1251 Purpose: M3UA reports it has successfully processed an incoming ASP 1252 Inactive message from its peer. 1254 M-AS_ACTIVE indication 1255 Direction: M3UA -> LM 1256 Purpose: M3UA reports that an AS has moved to the AS-ACTIVE state. 1258 M-AS_INACTIVE indication 1259 Direction: M3UA -> LM 1260 Purpose: M3UA reports that an AS has moved to the AS-INACTIVE state. 1262 M-AS_DOWN indication 1263 Direction: M3UA -> LM 1264 Purpose: M3UA reports that an AS has moved to the AS-DOWN state. 1266 If dynamic registration of RK is supported by the M3UA layer, the layer 1267 MAY support the following additional primitives: 1269 M-RK_REG request 1270 Direction: LM -> M3UA 1271 Purpose: LM requests ASP to register RK(s) with its peer by sending 1272 REG REQ message 1274 M-RK_REG confirm 1275 Direction: M3UA -> LM 1276 Purpose: ASP reports that it has received REG RSP message with 1277 registration status as successful from its peer. 1279 M-RK_REG indication 1280 Direction: M3UA -> LM 1281 Purpose: M3UA informs LM that it has successfully processed an 1282 incoming REG REQ message. 1284 M-RK_DEREG request 1285 Direction: LM -> M3UA 1286 Purpose: LM requests ASP to de-register RK(s) with its peer by 1287 sending DEREG REQ message. 1289 M-RK_DEREG confirm 1290 Direction: M3UA -> LM 1291 Purpose: ASP reports that it has received DEREG REQ message with de- 1292 registration status as successful from its peer. 1294 M-RK_DEREG indication 1295 Direction: M3UA -> LM 1296 Purpose: M3UA informs LM that it has successfully processed an 1297 incoming DEREG REQ from its peer. 1299 2.0 Conventions 1301 The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD 1302 NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when they appear 1303 in this document, are to be interpreted as described in [RFC2119]. 1305 3. M3UA Protocol Elements 1307 The general M3UA message format includes a Common Message Header 1308 followed by zero or more parameters as defined by the Message Type. 1309 For forward compatibility, all Message Types may have attached 1310 parameters even if none are specified in this version. 1312 3.1 Common Message Header 1314 The protocol messages for MTP3-User Adaptation require a message header 1315 which contains the adaptation layer version, the message type, and 1316 message length. 1318 0 1 2 3 1319 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 | Version | Reserved | Message Class | Message Type | 1322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1323 | Message Length | 1324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1325 \ \ 1326 / / 1328 All fields in an M3UA message MUST be transmitted in the network byte 1329 order, unless otherwise stated. 1331 3.1.1 M3UA Protocol Version: 8 bits (unsigned integer) 1333 The version field contains the version of the M3UA adaptation layer. 1335 The supported versions are the following: 1337 1 Release 1.0 1339 3.1.2 Message Classes and Types 1341 The following list contains the valid Message Classes: 1343 Message Class: 8 bits (unsigned integer) 1345 The following list contains the valid Message Type Classes: 1347 0 Management (MGMT) Message 1348 1 Transfer Messages 1349 2 SS7 Signalling Network Management (SSNM) Messages 1350 3 ASP State Maintenance (ASPSM) Messages 1351 4 ASP Traffic Maintenance (ASPTM) Messages 1352 5 Reserved for Other Sigtran Adaptation Layers 1353 6 Reserved for Other Sigtran Adaptation Layers 1354 7 Reserved for Other Sigtran Adaptation Layers 1355 8 Reserved for Other Sigtran Adaptation Layers 1356 9 Routing Key Management (RKM) Messages 1357 10 to 127 Reserved by the IETF 1358 128 to 255 Reserved for IETF-Defined Message Class extensions 1360 Message Type: 8 bits (unsigned integer) 1362 The following list contains the message types for the defined 1363 messages. 1365 Management (MGMT) Messages (See Section 3.6) 1367 0 Error (ERR) 1368 1 Notify (NTFY) 1369 2 to 127 Reserved by the IETF 1370 128 to 255 Reserved for IETF-Defined MGMT extensions 1372 Transfer Messages (See Section 3.3) 1374 0 Reserved 1375 1 Payload Data (DATA) 1376 2 to 127 Reserved by the IETF 1377 128 to 255 Reserved for IETF-Defined Transfer extensions 1379 SS7 Signalling Network Management (SSNM) Messages (See Section 1380 3.4) 1382 0 Reserved 1383 1 Destination Unavailable (DUNA) 1384 2 Destination Available (DAVA) 1385 3 Destination State Audit (DAUD) 1386 4 SS7 Network Congestion (SCON) 1387 5 Destination User Part Unavailable (DUPU) 1388 6 Destination Restricted (DRST) 1389 7 to 127 Reserved by the IETF 1390 128 to 255 Reserved for IETF-Defined SSNM extensions 1392 ASP State Maintenance (ASPSM) Messages (See Section 3.5) 1394 0 Reserved 1395 1 ASP Up (ASPUP) 1396 2 ASP Down (ASPDN) 1397 3 Heartbeat (BEAT) 1398 4 ASP Up Acknowledgement (ASPUP ACK) 1399 5 ASP Down Acknowledgement (ASPDN ACK) 1400 6 Heatbeat Acknowledgement (BEAT ACK) 1401 7 to 127 Reserved by the IETF 1402 128 to 255 Reserved for IETF-Defined ASPSM extensions 1404 ASP Traffic Maintenance (ASPTM) Messages (See Section 3.5) 1406 0 Reserved 1407 1 ASP Active (ASPAC) 1408 2 ASP Inactive (ASPIA) 1409 3 ASP Active Acknowledgement (ASPAC ACK) 1410 4 ASP Inactive Acknowledgement (ASPIA ACK) 1411 5 to 127 Reserved by the IETF 1412 128 to 255 Reserved for IETF-Defined ASPTM extensions 1414 Routing Key Management (RKM) Messages (See Section 3.7) 1416 0 Reserved 1417 1 Registration Request (REG REQ) 1418 2 Registration Response (REG RSP) 1419 3 Deregistration Request (DEREG REQ) 1420 4 Deregistration Response (DEREG RSP) 1421 5 to 127 Reserved by the IETF 1422 128 to 255 Reserved for IETF-Defined RKM extensions 1424 3.1.3 Reserved: 8 bits 1426 The Reserved field SHOULD be set to all '0's and ignored by the 1427 receiver. 1429 3.1.4 Message Length: 32-bits (unsigned integer) 1431 The Message Length defines the length of the message in octets, 1432 including the Common Header. For messages with a final parameter 1433 containing padding, the parameter padding MUST be included in the 1434 Message Length. 1436 Note: A receiver SHOULD accept the message whether or not the final 1437 parameter padding is included in the message length. 1439 3.2 Variable-Length Parameter Format 1441 M3UA messages consist of a Common Header followed by zero or more 1442 variable length parameters, as defined by the message type. All the 1443 parameters contained in a message are defined in a Tag-Length-Value 1444 format as shown below. 1446 0 1 2 3 1447 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1449 | Parameter Tag | Parameter Length | 1450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1451 \ \ 1452 / Parameter Value / 1453 \ \ 1454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1456 Where more than one parameter is included in a message, the parameters 1457 may be in any order, except where explicitly mandated. A receiver 1458 SHOULD accept the parameters in any order. 1460 Parameter Tag: 16 bits (unsigned integer) 1462 The Tag field is a 16-bit identifier of the type of parameter. It 1463 takes a value of 0 to 65534. Common parameters used by adaptation 1464 layers are in the range of 0x00 to 0xff. M3UA-specific parameters 1465 have Tags in the range 0x80 to 0xbf. The parameter Tags defined are 1466 as follows: 1468 0x00 Reserved 1469 0x80 Network Appearance 1470 0x81 Protocol Data 1 1471 0x82 Protocol Data 2 1472 0x04 INFO String 1473 0x83 Affected Destinations 1474 0x06 Routing Context 1475 0x07 Diagnostic Information 1476 0x09 Heartbeat Data 1477 0x84 User/Cause 1478 0x0a Reason 1479 0x0b Traffic Mode Type 1480 0x0c Error Code 1481 0x0d Status 1482 0x85 Congestion Indications 1483 0x86 Concerned Destination 1484 0x87 Routing Key 1485 0x88 Registration Result 1486 0x89 De-registration Result 1487 0x8a Local_Routing Key Identifier 1488 0x8b Destination Point Code 1489 0x8c Service Indicators 1490 0x8d Subsystem Numbers 1491 0x8e Originating Point Code List 1492 0x8f Circuit Range 1493 0x90 Registration Results 1494 0x91 De-Registration Results 1495 0x92 to ffff...Reserved by the IETF 1497 The value of 65535 is reserved for IETF-defined extensions. Values 1498 other than those defined in specific parameter description are 1499 reserved for use by the IETF. 1501 Parameter Length: 16 bits (unsigned integer) 1503 The Parameter Length field contains the size of the parameter in 1504 bytes, including the Parameter Tag, Parameter Length, and Parameter 1505 Value fields. The Parameter Length does not include any padding 1506 bytes. 1508 Parameter Value: variable-length. 1510 The Parameter Value field contains the actual information to be 1511 transferred in the parameter. 1513 The total length of a parameter (including Tag, Parameter Length and 1514 Value fields) MUST be a multiple of 4 bytes. If the length of the 1515 parameter is not a multiple of 4 bytes, the sender pads the 1516 Parameter at the end (i.e., after the Parameter Value field) with 1517 all zero bytes. The length of the padding is NOT included in the 1518 parameter length field. A sender SHOULD NOT pad with more than 3 1519 bytes. The receiver MUST ignore the padding bytes. 1521 3.3 Transfer Messages 1523 The following section describes the Transfer messages and parameter 1524 contents. 1526 3.3.1 Payload Data Message (DATA) 1528 The DATA message contains the SS7 MTP3-User protocol data, which is an 1529 MTP-TRANSFER primitive, including the complete MTP3 Routing Label. The 1530 DATA message contains the following variable length parameters: 1532 Network Appearance Optional 1533 Protocol Data 1 or 2 Mandatory 1535 The following format MUST be used for the Data Message: 1537 0 1 2 3 1538 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1540 | Tag = 0x80 | Length = 8 | 1541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1542 | Network Appearance | 1543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 | Tag = 0x81 or 0x82 | Length | 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1546 \ \ 1547 / Protocol Data / 1548 \ \ 1549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1551 Network Appearance: 32-bits (unsigned integer) 1553 The optional Network Appearance parameter identifies the SS7 network 1554 context for the message, for the purposes of logically separating 1555 the signalling traffic between the SGP and the ASP over a common 1556 SCTP association. An example is where an SG is logically 1557 partitioned to appear as an element in four different national SS7 1558 networks. 1560 In a DATA message, the Network Appearance implicitly defines the SS7 1561 Point Code format used, the SS7 Network Indicator value, and the 1562 MTP3 and possibly the MTP3-User protocol type/variant/version used 1563 within the SS7 network partition. Where an SG operates in the 1564 context of a single SS7 network, or individual SCTP associations are 1565 dedicated to each SS7 network context, the Network Appearance 1566 parameter is not required. In other cases the parameter MUST be 1567 included. 1569 The Network Appearance parameter value is of local significance 1570 only, coordinated between the SGP and ASP. Therefore, in the case 1571 where an ASP is connected to more than one SGP, the same SS7 network 1572 context may be identified by different Network Appearance values 1573 depending over which SGP a message is being transmitted/received. 1575 Where the optional Network Appearance parameter is present, it must 1576 be the first parameter in the message as it defines the format of 1577 the Protocol Data field 1579 One of two possible Protocol Data parameters are included in a DATA 1580 message: Protocol Data 1 or Protocol Data 2. 1582 Protocol Data 1 or 2: variable length 1584 The Protocol Data 1 parameter contains the original SS7 MTP3 1585 message, including the Service Information Octet and Routing Label. 1587 The Protocol Data 1 parameter contains the following fields: 1589 Service Information Octet. Includes: 1590 Service Indicator, 1591 Network Indicator, 1592 and Spare/Priority codes. 1594 Routing Label. Includes: 1595 Destination Point Code, 1596 Originating Point Code, 1597 And Signalling Link Selection Code (SLS). 1599 User Protocol Data. Includes: 1600 MTP3-User protocol elements (e.g., ISUP, SCCP, or TUP 1601 parameters). 1603 The Protocol Data 2 parameter contains all the information in 1604 Protocol Data 1 as described above, plus the MTP2 Length Indicator 1605 octet. The MTP2 Length Indicator (LI) octet appears before the SIO 1606 and Routing Label information. The MTP2 Length Indicator octet is 1607 required for some national MTP variants that use the spare bits in 1608 the LI to carry additional information of interest to the MTP3 and 1609 MTP3-User (e.g., the Japan TTC standard use of LI spare bits to 1610 indicate message priority) 1612 The Payload Data format is as defined in the relevant MTP standards 1613 for the SS7 protocol being transported. The format is either 1614 implicitly known or identified by the Network Appearance parameter. 1615 Note: In the SS7 Recommendations, the format of the messages and 1616 fields within the messages are based on bit transmission order. In 1617 these recommendations the Least Significant Bit (LSB) of each field 1618 is positioned to the right. The received SS7 fields are populated 1619 octet by octet as received into the 4-octet word as shown in the two 1620 examples below. 1622 For the ANSI protocol example, the Protocol Data 1 field format is 1623 shown below: 1625 0 1 2 3 1626 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1628 | SIO | DPC Member | DPC Cluster | DPC Network | 1629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1630 | OPC Member | OPC Cluster | OPC Network | SLS | 1631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 \ \ 1633 / Protocol Data / 1634 \ \ 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1637 |MSB---------------------------------------------------------LSB| 1639 Within each octet the Least Significant Bit (LSB) per the SS7 1640 Recommendations is to the right (e.g., bit 7 of SIO is the LSB). 1642 For the ITU international protocol example (with the 3/8/3 Point 1643 Code format), the Protocol Data 1 field is shown below. 1645 0 1 2 3 1646 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 | SIO | DPC | DPC |OPC| DPC | DPC | OPC |@| 1649 | | Region *| SP *|SP*|Zone*| reg.| Region *| | 1650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1651 | SLS | OPC |$| Protocol | 1652 | *|Zone*| | Data | 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 * marks LSB of each field; @ = OPC SP MSB; $ = OPC region MSB 1657 3.4 SS7 Signalling Network Management (SSNM) Messages 1659 3.4.1 Destination Unavailable (DUNA) 1661 The DUNA message is sent from all SGPs in an SG to all concerned ASPs 1662 to indicate that the SG has determined that one or more SS7 1663 destinations are unreachable. It is also sent by an SGP in response to 1664 a message from the ASP to an unreachable SS7 destination. As an 1665 implementation option the SG may suppress the sending of subsequent 1666 "response" DUNA messages regarding a certain unreachable SS7 1667 destination for a certain period in order to give the remote side time 1668 to react. The MTP3-User at the ASP is expected to stop traffic to the 1669 affected destination through the SGPs initiating the DUNA message as 1670 per the defined MTP3-User procedures. 1672 The DUNA message contains the following parameters: 1674 Network Appearance Optional 1675 Affected Destinations Mandatory 1676 INFO String Optional 1678 The format for DUNA Message parameters is as follows: 1680 0 1 2 3 1681 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1683 | Tag = 0x80 | Length =8 | 1684 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1685 | Network Appearance | 1686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1687 | Tag = 0x83 | Length | 1688 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1689 | Mask | Affected DPC 1 | 1690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1691 \ \ 1692 / ... / 1693 \ \ 1694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1695 | Mask | Affected DPC n | 1696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1697 | Tag = 0x04 | Length | 1698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1699 \ \ 1700 / INFO String / 1701 \ \ 1702 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1704 Network Appearance: 32-bit unsigned integer 1706 See Section 3.3.1 1708 Affected Destinations: n x 32-bits 1710 The Affected Destinations parameter contains up to sixteen Affected 1711 Destination Point Code fields, each a three-octet parameter to allow 1712 for 14-, 16- and 24-bit binary formatted SS7 Point Codes. Affected 1713 Point Codes that are less than 24-bits, are padded on the left to 1714 the 24-bit boundary. The encoding is shown below for ANSI and ITU 1715 Point Code examples. 1717 ANSI 24-bit Point Code: 1719 0 1 2 3 1720 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1721 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1722 | Mask | Network | Cluster | Member | 1723 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1725 |MSB-----------------------------------------LSB| 1727 ITU 14-bit Point Code: 1729 0 1 2 3 1730 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1731 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1732 | Mask |0 0 0 0 0 0 0 0 0 0|Zone | Region | SP | 1733 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1735 |MSB--------------------LSB| 1737 It is optional to send an Affected Destinations parameter with more 1738 than one Affected DPC but it is mandatory to receive and process it. 1739 All the Affected DPCs included must be within the same Network 1740 Appearance. Including multiple Affected DPCs may be useful when 1741 reception of an MTP3 management message or a linkset event 1742 simultaneously affects the availability status of a list of 1743 destinations at an SG. 1745 Mask: 8-bits (unsigned integer) 1747 The Mask field associated with each Affected DPC in the Affected 1748 Destinations parameter, used to identify a contiguous range of 1749 Affected Destination Point Codes, independent of the point code 1750 format. Identifying a contiguous range of Affected DPCs may be 1751 useful when reception of an MTP3 management message or a linkset 1752 event simultaneously affects the availability status of a series of 1753 destinations at an SG. For example, if all DPCs in an ANSI cluster 1754 are determined to be unavailable due to local linkset 1755 unavailability, the DUNA could identify potentially 256 Affected 1756 DPCs in a single Affected DPC field. 1758 The Mask parameter represents a bit mask that can be applied to the 1759 related Affected DPC field. The bit mask identifies how many bits 1760 of the Affected DPC field are significant and which are effectively 1761 "wildcarded". For example, a mask of "8" indicates that the least 1762 significant eight bits of the DPC is "wildcarded". For an ANSI 24- 1763 bit Affected DPC, this is equivalent to signalling that all DPCs in 1764 an ANSI Cluster are unavailable. A mask of "3" indicates that the 1765 least significant three bits of the DPC is "wildcarded". For a 14- 1766 bit ITU Affected DPC, this is equivalent to signaling that an ITU 1767 Region is unavailable. A mask value equal to the number of bits in 1768 the DPC indicates that the entire network appearance is affected � 1769 this is used to indicate network isolation to the ASP. 1771 INFO String: variable length 1773 The optional INFO String parameter can carry any 8-bit ASCII 1774 character string along with the message. Length of the INFO 1775 String parameter is from 0 to 255 characters. No procedures are 1776 presently identified for its use but the INFO String MAY be used by 1777 Operators to identify in text form the location reflected by the 1778 Affected DPC for debugging purposes. 1780 3.4.2 Destination Available (DAVA) 1782 The DAVA message is sent from the SGP to all concerned ASPs to indicate 1783 that the SG has determined that one or more SS7 destinations are now 1784 reachable (and not restricted), or in response to a DAUD message if 1785 appropriate. The ASP MTP3-User protocol is informed and may now resume 1786 traffic to the affected destination. The ASP M3UA layer routes the 1787 MTP3_user traffic through the SGP(s) initiating the DAVA message. 1789 The DAVA message contains the following parameters: 1791 Network Appearance Optional 1792 Affected Destinations Mandatory 1793 INFO String Optional 1795 The format and description of the Network Appearance, Affected 1796 Destinations and INFO String parameters is the same as for the DUNA 1797 message (See Section 3.4.1). 1799 3.4.3 Destination State Audit (DAUD) 1801 The DAUD message MAY be sent from the ASP to the SGP to audit the 1802 availability/congestion state of SS7 routes to one or more affected 1803 destinations. 1805 The DAUD message contains the following parameters: 1807 Network Appearance Optional 1808 Affected Destinations Mandatory 1809 INFO String Optional 1811 The format and description of DAUD Message parameters is the same as 1812 for the DUNA message (See Section 3.4.1). 1814 3.4.4 SS7 Network Congestion (SCON) 1816 The SCON message can be sent from the SGP to all concerned ASPs to 1817 indicate congestion in the SS7 network to one or more destinations, or 1818 to an ASP in response to a DATA or DAUD message as appropriate. For 1819 some MTP protocol variants (e.g., ANSI MTP) the SCON message may be 1820 sent when the SS7 congestion level changes. The SCON message MAY also 1821 be sent from the M3UA layer of an ASP to an M3UA peer indicating that 1822 the M3UA layer or the ASP is congested. 1824 The SCON message contains the following parameters: 1826 Network Appearance Optional 1827 Affected Destinations Mandatory 1828 Concerned Destination Optional 1829 Congestion Indications Optional 1830 INFO String Optional 1832 The format for SCON Message parameters is as follows: 1834 0 1 2 3 1835 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1836 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1837 | Tag = 0x80 | Length =8 | 1838 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1839 | Network Appearance | 1840 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1841 | Tag = 0x83 | Length | 1842 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1843 | Mask | Affected DPC 1 | 1844 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1845 \ \ 1846 / ... / 1847 \ \ 1848 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1849 | Mask | Affected DPC n | 1850 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1851 | Tag = 0x86 | Length | 1852 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1853 | reserved | Concerned DPC | 1854 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1855 | Tag = 0x85 | Length | 1856 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1857 | Reserved | Cong. Level | 1858 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1859 | Tag = 0x04 | Length | 1860 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1861 \ \ 1862 / INFO String / 1863 \ \ 1864 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1866 The format and description of the Network Appearance, Affected 1867 Destinations, and INFO String parameters is the same as for the DUNA 1868 message (See Section 3.4.1). 1870 The Affected Destinations parameter can be used to indicate congestion 1871 of multiple destinations or ranges of destinations. However, an SCON 1872 message MUST not be delayed in order to "collect" individual congested 1873 destinations into a single SCON message as any delay might affect the 1874 timing of congestion indications to the M3UA Users. One use for 1875 including a range of Congested DPCs is when the SG supports an ANSI 1876 cluster route set to the SS7 network that becomes congested due to 1877 outgoing link set congestion. 1879 Concerned Destination: 32-bits 1881 The optional Concerned Destination parameter is only used if the 1882 SCON message is sent from an ASP to the SGP. It contains the point 1883 code of the originator of the message that triggered the SCON 1884 message. The Concerned Destination parameter contains one Concerned 1885 Destination Point Code field, a three-octet parameter to allow for 1886 14-, 16- and 24-bit binary formatted SS7 Point Codes. A Concerned 1887 Point Code that is less than 24-bits is padded on the left to the 1888 24-bit boundary. Any resulting Transfer Controlled (TFC) message 1889 from the SG is sent to the Concerned Point Code using the single 1890 Affected DPC contained in the SCON message to populate the 1891 (affected) Destination field of the TFC message 1893 Congested Indications: 32-bits 1895 The optional Congestion Indications parameter contains a Congestion 1896 Level field. This optional parameter is used to communicate 1897 congestion levels in national MTP networks with multiple congestion 1898 thresholds, such as in ANSI MTP3. For MTP congestion methods 1899 without multiple congestion levels (e.g., the ITU international 1900 method) the parameter is not included. 1902 Congestion Level field: 8-bits (unsigned integer) 1904 The Congestion Level field, associated with all of the Affected 1905 DPC(s) in the Affected Destinations parameter, contains one of the 1906 Following values: 1908 0 No Congestion or Undefined 1909 1 Congestion Level 1 1910 2 Congestion Level 2 1911 3 Congestion Level 3 1913 The congestion levels are defined in the congestion method in the 1914 appropriate national MTP recommendations [14,15]. 1916 3.4.5 Destination User Part Unavailable (DUPU) 1918 The DUPU message is used by an SGP to inform an ASP that a remote peer 1919 MTP3-User Part (e.g., ISUP or SCCP) at an SS7 node is unavailable. 1921 The DUPU message contains the following parameters: 1923 Network Appearance Optional 1924 Affected Destinations Mandatory 1925 User/Cause Mandatory 1926 INFO String Optional 1928 The format for DUPU message parameters is as follows: 1930 0 1 2 3 1931 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1932 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1933 | Tag = 0x80 | Length | 1934 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1935 | Network Appearance | 1936 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1937 | Tag = 0x83 | Length = 8 | 1938 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1939 | Mask = 0 | Affected DPC | 1940 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1941 | Tag = 0x84 | Length = 8 | 1942 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1943 | Cause | User | 1944 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1945 | Tag = 0x04 | Length | 1946 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1947 \ \ 1948 / INFO String / 1949 \ \ 1950 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1952 User/Cause: 32-bits 1954 The Unavailability Cause and MTP3-User Identity fields, associated 1955 with the Affected DPC in the Affected Destinations parameter, are 1956 encoded as follows: 1958 Unavailability Cause field: 16-bits (unsigned integer) 1960 The Unavailability Cause parameter provides the reason for the 1961 unavailability of the MTP3-User. The valid values for the 1962 Unavailability Cause parameter are shown in the following table. 1963 The values agree with those provided in the SS7 MTP3 User Part 1964 Unavailable message. Depending on the MTP3 protocol used in the 1965 Network Appearance, additional values may be used - the 1966 specification of the relevant MTP3 protocol variant/version 1967 recommendation is definitive. 1969 0 Unknown 1970 1 Unequipped Remote User 1971 2 Inaccessible Remote User 1973 MTP3-User Identity field: 16-bits (unsigned integer) 1975 The MTP3-User Identity describes the specific MTP3-User that is 1976 unavailable (e.g., ISUP, SCCP, ...). Some of the valid values for 1977 the MTP3-User Identity are shown below. The values align with those 1978 provided in the SS7 MTP3 User Part Unavailable message and Service 1979 Indicator. Depending on the MTP3 protocol variant/version used in 1980 the network appearance, additional values may be used. The relevant 1981 MTP3 protocol variant/version recommendation is definitive. 1983 0 to 2 Reserved 1984 3 SCCP 1985 4 TUP 1986 5 ISUP 1987 6 to 8 Reserved 1988 9 Broadband ISUP 1989 10 Satellite ISUP 1990 11 Reserved 1991 12 AAL type 2 Signalling 1992 13 Bearer Independent Call Control (BICC) 1993 14 Gateway Control Protocol 1994 15 Reserved 1996 The format and description of the Affected Destinations parameter is 1997 the same as for the DUNA message (See Section 3.4.1.) except that the 1998 Mask field is not used and only a single Affected DPC is included. 1999 Ranges and lists of Affected DPCs cannot be signalled in a DUPU 2000 message, but this is consistent with UPU operation in the SS7 network. 2001 The Affected Destinations parameter in an MTP3 User Part Unavailable 2002 message (UPU) received by an SGP from the SS7 network contains only one 2003 destination. 2005 The format and description of the Network Appearance and INFO String 2006 parameters is the same as for the DUNA message (See Section 3.4.1). 2008 3.4.6 Destination Restricted (DRST) 2010 The DRST message is optionally sent from the SGP to all concerned ASPs 2011 to indicate that the SG has determined that one or more SS7 2012 destinations are now restricted from the point of view of the SGP, or 2013 in response to a DAUD message if appropriate. The M3UA layer at the ASP 2014 is expected to send traffic to the affected destination via an 2015 alternate SGP of equal priority, but only if such an alternate route 2016 exists and is available. If the affected destination is currently 2017 considered unavailable by the ASP, The MTP3-User should be informed 2018 that traffic to the affected destination can be resumed. In this case, 2019 the M3UA layer should route the traffic through the SGP initiating the 2020 DRST message. 2022 This message is optional for the SGP to send and it is optional for the 2023 ASP to act on any information received in the message. It is for use in 2024 the "STP" case described in Section 1.4.1. 2026 The DRST message contains the following parameters: 2028 Network Appearance Optional 2029 Affected Destinations Mandatory 2030 INFO String Optional 2032 The format and description of the Network Appearance, Affected 2033 Destinations and INFO String parameters is the same as for the DUNA 2034 message (See Section 3.4.1). 2036 3.5 ASP State Maintenance (ASPSM) Messages 2038 3.5.1 ASP Up 2040 The ASP Up message is used to indicate to a remote M3UA peer that the 2041 adaptation layer is ready to receive any SSNM or ASPSM/ASPTM messages 2042 for all Routing Keys that the ASP is configured to serve. 2044 The ASP Up message contains the following parameters: 2046 INFO String Optional 2048 The format for ASP Up message parameters is as follows: 2050 0 1 2 3 2051 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2052 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2053 | Tag = 0x04 | Length | 2054 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2055 \ \ 2056 / INFO String / 2057 \ \ 2058 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2060 The format and description of the optional INFO String parameter is the 2061 same as for the DUNA message (See Section 3.4.1). 2063 3.5.2 ASP Up Acknowledgement (ASP Up Ack) 2065 The ASP UP Ack message is used to acknowledge an ASP Up message 2066 received from a remote M3UA peer. 2068 The ASP Up Ack message contains the following parameters: 2070 INFO String (optional) 2072 The format for ASP Up Ack message parameters is as follows: 2074 0 1 2 3 2075 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2076 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2077 | Tag =0x04 | Length | 2078 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2079 \ \ 2080 / INFO String / 2081 \ \ 2082 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2084 The format and description of the optional INFO String parameter is the 2085 same as for the DUNA message (See Section 3.4.1). The INFO String in 2086 an ASP Up Ack message is independent from the INFO String in the ASP Up 2087 message (i.e., it does not have to echo back the INFO String received). 2089 3.5.3 ASP Down 2091 The ASP Down message is used to indicate to a remote M3UA peer that the 2092 adaptation layer is NOT ready to receive DATA, SSNM or ASPTM messages. 2094 The ASP Down message contains the following parameters: 2096 Reason Mandatory 2097 INFO String Optional 2099 The format for the ASP Down message parameters is as follows: 2101 0 1 2 3 2102 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2103 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2104 | Tag = 0x0a | Length | 2105 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2106 | Reason | 2107 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2108 | Tag =0x04 | Length | 2109 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2110 \ \ 2111 / INFO String / 2112 \ \ 2113 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2115 The format and description of the optional INFO String parameter is the 2116 same as for the DUNA message (See Section 3.4.1). 2118 Reason: 32-bit (unsigned integer) 2120 The Reason parameter indicates the reason that the remote M3UA 2121 adaptation layer is unavailable. The valid values for Reason are 2122 shown in the following table. 2124 0 Unspecified 2125 1 User Unavailable 2126 2 Management Blocking 2128 3.5.4 ASP Down Acknowledgement (ASP Down Ack) 2130 The ASP Down Ack message is used to acknowledge an ASP Down message 2131 received from a remote M3UA peer. 2133 The ASP Down Ack message contains the following parameters: 2135 Reason Mandatory 2136 INFO String Optional 2138 The format for the ASP Down Ack message parameters is as follows: 2140 0 1 2 3 2141 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2143 | Tag = 0x0a | Length | 2144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2145 | Reason | 2146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2147 | Tag = 0x04 | Length | 2148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2149 \ \ 2150 / INFO String / 2151 \ \ 2152 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2154 The format and description of the optional INFO String parameter is the 2155 same as for the DUNA message (See Section 3.4.1). 2157 The INFO String in an ASP Down Ack message is independent from the INFO 2158 String in the ASP Down message (i.e., it does not have to echo back the 2159 INFO String received). 2161 The format of the Reason parameter is the same as for the ASP-Down 2162 message. (See Section 3.5.3). 2164 3.5.5 Heartbeat (BEAT) 2166 The BEAT message is optionally used to ensure that the M3UA peers 2167 are still available to each other. It is recommended for use when the 2168 M3UA runs over a transport layer other than the SCTP, which has its own 2169 heartbeat. 2171 The BEAT message contains the following parameters: 2173 Heatbeat Data Optional 2175 The format for the BEAT message is as follows: 2177 0 1 2 3 2178 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2180 | Tag = 0x09 | Length | 2181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2182 \ \ 2183 / Heartbeat Data / 2184 \ \ 2185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2187 The Heartbeat Data parameter contents are defined by the sending node. 2188 The Heartbeat Data could include, for example, a Heartbeat Sequence 2189 Number and/or Timestamp. The receiver of a BEAT message does not 2190 process this field as it is only of significance to the sender. The 2191 receiver MUST respond with a BEAT Ack message. 2193 3.5.6 Heartbeat Acknowledgement (BEAT Ack) 2195 The BEAT Ack message is sent in response to a received BEAT 2196 message. It includes all the parameters of the received BEAT 2197 message, without any change. 2199 3.6 Routing Key Management (RKM) Messages 2201 3.6.1 Registration Request (REG REQ) 2203 The REG REQ message is sent by an ASP to indicate to a remote M3UA peer 2204 that it wishes to register one or more given Routing Keys with the 2205 remote peer. Typically, an ASP would send this message to an SGP, and 2206 expects to receive a REG RSP message in return with an associated 2207 Routing Context value. 2209 The REG REQ message contains the following parameters: 2211 Routing Key Mandatory 2213 The format for the REG REQ message is as follows: 2215 0 1 2 3 2216 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2218 | Tag = 0x87 | Length | 2219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2220 \ \ 2221 / Routing Key 1 / 2222 \ \ 2223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2224 \ \ 2225 / ... / 2226 \ \ 2227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2228 | Tag = 0x87 | Length | 2229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2230 \ \ 2231 / Routing Key n / 2232 \ \ 2233 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2235 Routing Key: variable length 2237 The Routing Key parameter is mandatory. The sender of this message 2238 expects that the receiver of this message will create a Routing 2239 Key entry and assign a unique Routing Context value to it, if the 2240 Routing Key entry does not already exist. 2242 The Routing Key parameter may be present multiple times in the same 2243 message. This is used to allow the registration of multiple Routing 2244 Keys in a single message. 2246 The format of the Routing Key parameter is as follows. 2248 0 1 2 3 2249 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2251 | Local-RK-Identifier | 2252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2253 | Traffic Mode Type | 2254 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2255 | Destination Point Code | 2256 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2257 | Network Appearance (optional) | 2258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2259 | SI (optional) | 2260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2261 | SSN (optional) | 2262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2263 | Origination Point Code List (optional) | 2264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2265 | Circuit Range List (optional) | 2266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2268 Local-RK-Identifier: 32-bit integer 2270 The mandatory Local-RK-Identifier field is used to uniquely identify 2271 the registration request. The Identifier value is assigned by the 2272 ASP, and is used to correlate the response in an REG RSP message 2273 with the original registration request. The Identifier value must 2274 remain unique until the REG RSP message is received. 2276 The format of the Local-RK-Identifier field is as follows: 2278 0 1 2 3 2279 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2281 | ag = 0x8a | Length = 8 | 2282 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2283 | Local-RK-Identifier value | 2284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2286 Traffic Mode Type: 32-bit (unsigned integer) 2288 The Traffic Mode Type parameter is mandatory and identifies the 2289 traffic mode of operation of the ASP(s) within an Application 2290 Server. The valid values for Traffic Mode Type are shown in the 2291 following table: 2293 1 Over-ride 2294 2 Load-share 2296 If the receiver of the REG REQ creates a new Routing Key entry, then 2297 the Traffic Mode Type sets the traffic mode for the new Application 2298 Server. If the receiver of the REG REQ determines that a matching 2299 Routing Key already exists, the Traffic Mode Type MUST match the 2300 existing traffic mode for the AS. 2302 Destination Point Code: 2304 The Destination Point Code parameter is mandatory, and identifies 2305 the Destination Point Code of incoming SS7 traffic for which the ASP 2306 is registering. The format is the same as described for the 2307 Affected Destination parameter in the DUNA message (See Section 2308 3.4.1). Its format is: 2310 0 1 2 3 2311 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2313 | Tag = 0x8b | Length = 8 | 2314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2315 | Mask = 0 | Destination Point Code | 2316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2318 Network Appearance: 2320 The optional Network Appearance parameter field identifies the SS7 2321 network context for the Routing Key, and has the same format as in 2322 the DATA message (See Section 3.3.1). The absence of the Network 2323 Appearance parameter in the Routing Key indicates the use 2324 of any Network Appearance value, Its format is: 2326 0 1 2 3 2327 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2329 | Tag = 0x80 | Length = 8 | 2330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2331 | Network Appearance | 2332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2334 Service Indicators (SI): n X 8-bit integers 2336 The optional SI field contains one or more Service Indicators from 2337 the values as described in the MTP3-User Identity field of the DUPU 2338 message. The absence of the SI parameter in the Routing Key 2339 indicates the use of any SI value, excluding of course MTP 2340 management. Where an SI parameter does not contain a multiple of 2341 four SIs, the parameter is padded out to 32-byte alignment. An 2342 SI value of zero is not valid in M3UA. The SI format is: 2344 0 1 2 3 2345 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2347 | Tag = 0x8c | Length | 2348 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2349 | SI #1 | SI #2 | SI #3 | SI #4 | 2350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2351 / ... / 2352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2353 | SI #n | 0 Padding, if necessary | 2354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2356 Subsystem Numbers (SSN): n X 8-bit integers 2358 The optional SSN field contains one or more SCCP subsystem numbers, 2359 and is used in conjunction with an SI values of 3 (i.e., SCCP) only. 2360 The absence of the SSN parameter in the Routing Key indicates the 2361 use of any SSN value, in the case of SCCP traffic. Where an SSN 2362 parameter does not contain a multiple of four SSNs, the parameter is 2363 padded out to 32-byte alignment. The subsystem number values 2364 associated are defined by the local network operator, and typically 2365 follow ITU-T Recommendation Q.713 [5]. An SSN value of zero is not 2366 valid in M3UA. The format of this field is as follows: 2368 0 1 2 3 2369 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2370 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2371 | Tag = 0x8d | Length | 2372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2373 | SSN #1 | SSN #2 | SSN #3 | SSN #4 | 2374 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2375 / ... / 2376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2377 | SSN #n | 0 Padding, if necessary | 2378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2380 OPC List: 2382 The Originating Point Code List parameter contains one or more SS7 2383 OPC entries, and its format is the same as the Destination Point 2384 Code parameter. The absence of the OPC List parameter in the 2385 Routing Key indicates the use of any OPC value, 2386 0 1 2 3 2387 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2389 | Tag = 0x8e | Length | 2390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2391 | Mask = 0 | Origination Point Code #1 | 2392 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2393 | Mask = 0 | Origination Point Code #2 | 2394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2395 / ... / 2396 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2397 | Mask = 0 | Origination Point Code #n | 2398 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2400 Circuit Range: 2402 An ISUP controlled circuit is uniquely identified by the SS7 OPC, 2403 DPC and CIC value. For the purposes of identifying Circuit Ranges 2404 in an M3UA Routing Key, the optional Circuit Range parameter 2405 includes one or more circuit ranges, each identified by an OPC and 2406 Upper/Lower CIC value. The DPC is implicit as it is mandatory and 2407 already included in the DPC parameter of the Routing Key. The 2408 absence of the Circuit Range parameter in the Routing Key indicates 2409 the use of any Circuit Range values, in the case of ISUP/TUP 2410 traffic. The Origination Point Code is encoded the same as the 2411 Destination Point Code parameter, while the CIC values are 16-bit 2412 integers. 2414 The Circuit Range format is as follows: 2416 0 1 2 3 2417 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2419 | Tag = 0x8f | Length | 2420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2421 | Mask = 0 | Origination Point Code #1 | 2422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2423 | Lower CIC Value #1 | Upper CIC Value #1 | 2424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2425 | Mask = 0 | Origination Point Code #2 | 2426 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2427 | Lower CIC Value #2 | Upper CIC Value #2 | 2428 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2429 / ... / 2430 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2431 | Mask = 0 | Origination Point Code #n | 2432 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2433 | Lower CIC Value #n | Upper CIC Value #n | 2434 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2436 3.6 2 Registration Response (REG RSP) 2438 The REG RSP message is used as a response to the REG REQ message from a 2439 remote M3UA peer. It contains indications of success/failure for 2440 registration requests and returns a unique Routing Context value for 2441 successful registration requests, to be used in subsequent M3UA Traffic 2442 Management protocol. 2444 The REG RSP message contains the following parameters: 2446 Registration Results Mandatory 2448 The format for the REG RSP message is as follows: 2450 0 1 2 3 2451 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2452 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2453 | Tag = 0x90 | Length | 2454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2455 | Registration Result 1 | 2456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2457 / ... / 2458 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2459 | Registration Result n | 2460 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2462 Registration Results: 2464 The Registration Results parameter contains one or more results, 2465 each containing the registration status for a single Routing Key in 2466 an REG REQ message. The number of results in a single REG RSP 2467 message MAY match the number of Routing Key parameters found in the 2468 corresponding REG REQ message. The format of each result is as 2469 follows: 2471 0 1 2 3 2472 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2473 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2474 | Local-RK-Identifier value | 2475 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2476 | Registration Status | 2477 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2478 | Routing Context | 2479 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2481 Local-RK-Identifier: 32-bit integer 2483 The Local-RK-Identifier contains the same value as found in the 2484 matching Routing Key parameter found in the REG REQ message (See 2485 Section 3.5.5.1). 2487 Registration Status: 32-bit integer 2489 The Registration Result Status field indicates the success or the 2490 reason for failure of a registration request. 2492 Its values may be: 2494 0 Successfully Registered 2495 1 Error - Unknown 2496 2 Error - Invalid DPC 2497 3 Error - Invalid Network Appearance 2498 4 Error - Invalid Routing Key 2499 5 Error - Permission Denied 2500 6 Error - Cannot Support Unique Routing 2501 7 Error - Routing Key not Currently Provisioned 2502 8 Error - Insufficient Resources 2503 9 Error - Unsupported RK parameter Field 2504 10 Error � Unsupported/Invalid Traffic Handling Mode 2506 Routing Context: 32-bit integer 2508 The Routing Context field contains the Routing Context value for the 2509 associated Routing Key if the registration was successful. It is set 2510 to "0" if the registration was not successful. 2512 3.6.3 De-Registration Request (DEREG REQ) 2514 The DEREG REQ message is sent by an ASP to indicate to a remote M3UA 2515 peer that it wishes to de-register a given Routing Key. Typically, an 2516 ASP would send this message to an SGP, and expects to receive a DEREG 2517 RSP message in return with the associated Routing Context value. 2519 The DEREG REQ message contains the following parameters: 2521 Routing Context Mandatory 2523 The format for the DEREG REQ message is as follows: 2525 0 1 2 3 2526 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2528 | Tag = 0x06 | Length | 2529 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2530 \ \ 2531 / Routing Context / 2532 \ \ 2533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2535 Routing Context: n X 32-bit integers 2537 The Routing Context parameter contains (a list of) integers indexing 2538 the Application Server traffic that the sending ASP is currently 2539 registered to receive from the SGP but now wishes to deregister. 2541 3.6.4 De-Registration Response (DEREG RSP) 2543 The DEREG RSP message is used as a response to the DEREG REQ message 2544 from a remote M3UA peer. 2546 The DEREG RSP message contains the following parameters: 2548 De-registration Results Mandatory 2550 The format for the DEREG RSP message is as follows: 2552 0 1 2 3 2553 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2554 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2555 | Tag = 0x89 | Length | 2556 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2557 | De-Registration Result 1 | 2558 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2559 / ... / 2560 \ \ 2561 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2562 | De-Registration Result n | 2563 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2565 De-Registration Results: 2567 The De-Registration Results parameter contains one or more results, 2568 each containing the de-registration status for a single Routing 2569 Context in a DEREG REQ message. The number of results in a single 2570 DEREG RSP message MAY match the number of Routing Contexts found in 2571 the corresponding DEREG REQ message. The format of each result is 2572 as follows: 2574 0 1 2 3 2575 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2577 | Routing Context | 2578 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2579 | De-Registration Status | 2580 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2582 Routing Context: 32-bit integer 2584 The Routing Context field contains the Routing Context value of the 2585 matching Routing Key to deregister, as found in the DEREG REQ 2586 message. 2588 De-Registration Status: 32-bit integer 2590 The De-Registration Result Status field indicates the success or the 2591 reason for failure of the de-registration. 2593 Its values may be: 2594 0 Successfully De-registered 2595 1 Error - Unknown 2596 2 Error - Invalid Routing Context 2597 3 Error - Permission Denied 2598 4 Error - Not Registered 2599 5 Error � ASP Currently Active for Routing Context 2601 3.7 ASP Traffic Maintenance (ASPTM) Messages 2603 3.7.1 ASP Active 2605 The ASP Active message is sent by an ASP to indicate to a remote M3UA 2606 peer that it is ready to process signalling traffic for a particular 2607 Application Server. The ASP Active message affects only the ASP state 2608 for the Routing Keys identified by the Routing Contexts, if present. 2610 The ASP Active message contains the following parameters: 2612 Traffic Mode Type Mandatory 2613 Routing Context Optional 2614 INFO String Optional 2616 The format for the ASP Active message is as follows: 2618 0 1 2 3 2619 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2621 | Tag = 0x0b | Length | 2622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2623 | Traffic Mode Type | 2624 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2625 | Tag = 0x06 | Length | 2626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2627 \ \ 2628 / Routing Context / 2629 \ \ 2630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2631 | Tag = 0x04 | Length | 2632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2633 \ \ 2634 / INFO String / 2635 \ \ 2636 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2638 Traffic Mode Type: 32-bit (unsigned integer) 2640 The Traffic Mode Type parameter identifies the traffic mode of 2641 operation of the ASP within an AS. The valid values for Traffic Mode 2642 Type are shown in the following table: 2644 1 Over-ride 2645 2 Load-share 2646 3 Over-ride (Standby) 2647 4 Load-share (Standby) 2649 Within a particular Routing Context, Over-ride and Load-share, 2650 either active or standby, MUST NOT be mixed. The Over-ride value 2651 indicates that the ASP is operating in Over-ride mode, and the ASP 2652 takes over all traffic in an Application Server (i.e., primary/back- 2653 up operation), over-riding any currently active ASPs in the AS. In 2654 Load-share mode, the ASP will share in the traffic distribution with 2655 any other currently active ASPs. The Standby versions of the Over- 2656 ride and Load-share Types indicate that the ASP is declaring itself 2657 ready to accept traffic but leaves it up to the sender as to when 2658 the traffic is started. Over-ride (Standby) indicates that the 2659 traffic sender continues to use the currently active ASP until it 2660 can no longer send/receive traffic (i.e., the currently active ASP 2661 transitions to state ASP-DOWN or ASP-ACTIVE). At this point the 2662 sender MUST move the standby ASP to the ASP-ACTIVE state and 2663 commence traffic. Load-share (Standby) is similar - the sender 2664 continues to load-share to the current ASPs until it is determined 2665 that there is insufficient resources in the Load-share group. When 2666 there are insufficient ASPs, the sender MUST move the ASP to state 2667 ASP-ACTIVE. 2669 Routing Context: n X 32-bit integers 2671 The optional Routing Context parameter contains (a list of) integers 2672 indexing the Application Server traffic that the sending ASP is 2673 configured/registered to receive. 2675 There is one-to-one relationship between an index entry and an SGP 2676 Routing Key or AS Name. Because an AS can only appear in one 2677 Network Appearance, the Network Appearance parameter is not required 2678 in the ASP Active message. 2680 An Application Server Process may be configured to process traffic 2681 for more than one logical Application Server. From the perspective 2682 of an ASP, a Routing Context defines a range of signalling traffic 2683 that the ASP is currently configured to receive from the SGP. For 2684 example, an ASP could be configured to support call processing for 2685 multiple ranges of PSTN trunks and therefore receive related 2686 signalling traffic, identified by separate SS7 DPC/OPC/CIC ranges. 2688 The format and description of the optional INFO String parameter is the 2689 same as for the DUNA message (See Section 3.4.1). 2691 3.7.2 ASP Active Acknowledgement (ASP Active Ack) 2693 The ASP Active Ack message is used to acknowledge an ASP Active message 2694 received from a remote M3UA peer. In the case where an ASP Active 2695 (Over-ride (standby)) or ASP Active (Load-share (standby)) message is 2696 received, a second ASP Active Ack message is sent when the ASP is moved 2697 from the ASP-STANDBY to the ASP-ACTIVE state. 2699 The ASP Active Ack message contains the following parameters: 2701 Traffic Mode Type Mandatory 2702 Routing Context Optional 2703 INFO String Optional 2705 The format for the ASP Active Ack message is as follows: 2707 0 1 2 3 2708 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2710 | Tag = 0x0b | Length | 2711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2712 | Traffic Mode Type | 2713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2714 | Tag = 0x06 | Length | 2715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2716 \ \ 2717 / Routing Context / 2718 \ \ 2719 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2720 | Tag = 0x04 | Length | 2721 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2722 \ \ 2723 / INFO String / 2724 \ \ 2725 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2727 The format and description of the optional INFO String parameter is the 2728 same as for the DUNA message (See Section 3.4.1). 2730 The INFO String in an ASP Active Ack message is independent from the 2731 INFO String in the ASP Active message (i.e., it does not have to echo 2732 back the INFO String received). 2734 The format of the Traffic Mode Type and Routing Context parameters is 2735 the same as for the ASP Active message. (See Section 3.5.5). 2737 3.7.3 ASP Inactive 2739 The ASP Inactive message is sent by an ASP to indicate to a remote M3UA 2740 peer 2741 that it is no longer an active ASP to be used from within a list of 2742 ASPs. The ASP Inactive message affects only the ASP state in the 2743 Routing Keys identified by the Routing Contexts, if present. 2745 The ASP Inactive message contains the following parameters: 2747 Routing Context Optional 2748 INFO String Optional 2750 The format for the ASP Inactive message parameters is as follows: 2752 0 1 2 3 2753 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2754 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2755 | Tag = 0x06 | Length | 2756 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2757 \ \ 2758 / Routing Context / 2759 \ \ 2760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2761 | Tag = 0x04 | Length | 2762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2763 \ \ 2764 / INFO String / 2765 \ \ 2766 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2768 The format and description of the optional Routing Context and INFO 2769 String parameters is the same as for the ASP Active message (See 2770 Section 3.5.5.) 2772 3.7.4 ASP Inactive Acknowledgement (ASP Inactive Ack) 2774 The ASP Inactive Ack message is used to acknowledge an ASP Inactive 2775 message 2776 received from a remote M3UA peer. 2778 The ASP Inactive Ack message contains the following parameters: 2780 Routing Context Optional 2781 INFO String Optional 2783 The format for the ASP Inactive Ack message is as follows: 2785 0 1 2 3 2786 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2787 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2788 | Tag = 0x06 | Length | 2789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2790 \ \ 2791 / Routing Context* / 2792 \ \ 2793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2794 | Tag = 0x04 | Length | 2795 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2796 \ \ 2797 / INFO String / 2798 \ \ 2799 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2801 The format and description of the optional INFO String parameter is the 2802 same as for the DUNA message (See Section 3.4.1.) 2804 The INFO String in an ASP Inactive Ack message is independent from the 2805 INFO String in the ASP Inactive message (i.e., it does not have to echo 2806 back the INFO String received). 2808 The format of the Routing Context parameter is the same as for the ASP 2809 Inactive message. (See Section 3.5.7). 2811 3.8 Management (MGMT) Messages 2813 3.8.1 Error 2815 The Error message is used to notify a peer of an error event associated 2816 with an incoming message. For example, the message type might be 2817 unexpected given the current state, or a parameter value might be 2818 invalid. 2820 The Error message contains the following parameters: 2822 Error Code Mandatory 2823 Diagnostic Information Optional 2825 The format for the Error message is as follows: 2827 0 1 2 3 2828 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2829 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2830 | Tag = 0x0c | Length | 2831 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2832 | Error Code | 2833 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2834 | Tag = 0x07 | Length | 2835 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2836 \ \ 2837 / Diagnostic Information / 2838 \ \ 2839 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2841 Error Code: 32-bits (unsigned integer) 2843 The Error Code parameter indicates the reason for the Error Message. 2844 The Error parameter value can be one of the following values: 2846 1 Invalid Version 2847 2 Invalid Network Appearance 2848 3 Unsupported Message Class 2849 4 Unsupported Message Type 2850 5 Unsupported/Invalid Traffic Handling Mode 2851 6 Unexpected Message 2852 7 Protocol Error 2853 8 Invalid Routing Context 2854 9 Invalid Stream Identifier 2855 10 Invalid Parameter Value 2856 11 Refused - Management Blocking 2857 12 Unknown Routing Context 2859 The "Invalid Version" error is sent if a message was received with an 2860 invalid or unsupported version. The Error message contains the 2861 supported version in the Common header. The Error message could 2862 optionally provide the supported version in the Diagnostic Information 2863 area. 2865 The "Invalid Network Appearance" error is sent by a SGP if an ASP sends 2866 a message with an invalid (unconfigured) Network Appearance value. 2868 The "Unsupported Message Class" error is sent if a message with an 2869 unexpected or unsupported Message Class is received. 2871 The "Unsupported Message Type" error is sent if a message with an 2872 unexpected or unsupported Message Type is received. 2874 The "Unsupported/Invalid Traffic Handling Mode" error is sent by a SGP 2875 if an ASP sends an ASP Active message with an unsupported Traffic Mode 2876 Type or a Traffic Mode Type that is inconsistent with the presently 2877 configured mode for the Application Server. An example would be a case 2878 in which the SGP did not support load-sharing. 2880 The "Unexpected Message" error MAY be sent if a defined and recognized 2881 message is received that is not expected in the current state (in some 2882 cases the ASP may optionally silently discard the message and not send 2883 an Error message). For example, silent discard is used by an ASP if it 2884 received a DATA message from an SGP while it was in the ASP-INACTIVE 2885 state. 2887 The "Protocol Error" error is sent for any protocol anomaly(i.e., 2888 reception of a parameter that is syntactically correct but unexpected 2889 in the current situation. 2891 The "Invalid Routing Context" error is sent if a message is received 2892 from a peer with an invalid (unconfigured) Routing Context value. 2894 The "Invalid Stream Identifier" error is sent if a message is received 2895 on an unexpected SCTP stream (e.g., a Management message was received 2896 on a stream other than "0"). 2898 The " Invalid Parameter Value " error is sent if a message is received 2899 with an invalid parameter value (e.g., a DUPU message was received with 2900 a Mask value other than "0"). 2902 The "Refused - Management Blocking" error is sent when an ASP-Up or 2903 ASP-Active message is received and the request is refused for 2904 management reasons (e.g., management lock-out"). 2906 The "Unknown Routing Context" Error is sent if a message is received 2907 from a peer without a Routing Context parameter and it is not known by 2908 configuration data which Application Servers are referenced. 2910 Diagnostic Information: variable length 2912 When included, the optional Diagnostic information can be any 2913 information germane to the error condition, to assist in 2914 identification of the error condition. In the case of an Invalid 2915 Network Appearance, Traffic Handling Mode, Routing Context or 2916 Parameter Value, the Diagnostic information parameter MUST be added 2917 and include the offending parameter. In the other cases, the 2918 Diagnostic information MAY be the first 40 bytes of the offending 2919 message. 2921 Error messages MUST NOT be generated in response to other Error 2922 messages. 2924 3.8.2 Notify 2926 The Notify message used to provide an autonomous indication of M3UA 2927 events to an M3UA peer. 2929 The Notify message contains the following parameters: 2931 Status Mandatory 2932 Routing Context Optional 2933 INFO String Optional 2935 The format for the Notify message is as follows: 2937 0 1 2 3 2938 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2939 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2940 | Tag = 0x0d | Length | 2941 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2942 | Status Type | Status Information | 2943 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2944 | Tag = 0x06 | Length | 2945 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2946 \ \ 2947 / Routing Context / 2948 \ \ 2949 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2950 | Tag = 0x04 | Length | 2951 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2952 \ \ 2953 / INFO String / 2954 \ \ 2955 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2957 Status Type: 16-bits (unsigned integer) 2959 The Status Type parameter identifies the type of the Notify message. 2960 The following are the valid Status Type values: 2962 1 Application Server State Change (AS-State_Change) 2963 2 Other 2965 Status Information: 16-bits (unsigned integer) 2967 The Status Information parameter contains more detailed information 2968 for the notification, based on the value of the Status Type. 2970 If the Status Type is AS-State_Change the following Status 2971 Information values are used: 2973 1 reserved 2974 2 Application Server Inactive (AS-INACTIVE) 2975 3 Application Server Active (AS-ACTIVE) 2976 4 Application Server Pending (AS-PENDING) 2978 These notifications are sent from an SGP to an ASP upon a change in 2979 status of a particular Application Server. The value reflects the 2980 new state of the Application Server. 2982 If the Status Type is Other, then the following Status Information 2983 values are defined: 2985 1 Insufficient ASP Resources Active in AS 2986 2 Alternate ASP Active 2988 These notifications are not based on the SGP reporting the state change 2989 of an ASP or AS. In the Insufficent ASP Resources case, the SGP is 2990 indicating to an ASP_INACTIVE ASP in the AS that another ASP is 2991 required in order to handle the load of the AS (Load-sharing mode). 2992 For the Alternate ASP Active case, an ASP is informed when an alternate 2993 ASP transitions to the ASP-ACTIVE state in Over-ride mode. 2995 The format and description of the optional Routing Context and Info 2996 String parameters is the same as for the ASP Active message (See 2997 Section 2998 3.5.5.) 3000 4. Procedures 3002 The M3UA layer needs to respond to various local primitives it receives 3003 from other layers as well as the messages that it receives from the 3004 peer M3UA layer. This section describes the M3UA procedures in 3005 response to these events. 3007 4.1 Procedures to Support the M3UA-User and Layer Management Layers 3009 4.1.1 Receipt of Primitives from the M3UA-User 3011 On receiving an MTP-TRANSFER request primitive from an upper layer at 3012 an ASP/IPSP, or the nodal inter-working function at an SGP, the M3UA 3013 layer sends a corresponding DATA message (see Section 3) to its M3UA 3014 peer. The M3UA peer receiving the DATA message sends an MTP-TRANSFER 3015 indication primitive to the upper layer. 3017 The M3UA message distribution function (see Section 1.4.2.1) determines 3018 the Application Server (AS) based on comparing the information in the 3019 MTP-TRANSFER request primitive with a provisioned Routing Key. 3021 >From the list of ASPs within the AS table, an ASP in the ASP-ACTIVE 3022 state is selected and a DATA message is constructed and issued on the 3023 corresponding SCTP association. If more than one ASP is in the ASP- 3024 ACTIVE state (i.e., traffic is to be load-shared across more than one 3025 ASP), one of the ASPs in the ASP_ACTIVE state is selected from the 3026 list. The selection algorithm is implementation dependent but could, 3027 for example, be round-robin or based on, for example, the SLS or ISUP 3028 CIC. The appropriate selection algorithm must be chosen carefully as 3029 it is dependent on application assumptions and understanding of the 3030 degree of state coordination between the ASP_ACTIVE ASPs in the AS. 3032 In addition, the message needs to be sent on the appropriate SCTP 3033 stream, again taking care to meet the message sequencing needs of the 3034 signalling application. 3036 When there is no Routing Key match, or only a partial match, for an 3037 incoming SS7 message, a default treatment MUST be specified. Possible 3038 solutions are to provide a default Application Server at the SGP that 3039 directs all unallocated traffic to a (set of) default ASP(s), or to 3040 drop the message and provide a notification to Layer Management in an 3041 M-ERROR indication primitive. The treatment of unallocated traffic is 3042 implementation dependent. 3044 4.1.2 Receipt of Primitives from the Layer Management 3046 On receiving primitives from the local Layer Management, the M3UA layer 3047 will take the requested action and provide an appropriate response 3048 primitive to Layer Management. 3050 An M-SCTP_ESTABLISH request primitive from Layer Management at an ASP 3051 or IPSP will initiate the establishment of an SCTP association. The 3052 M3UA layer will attempt to establish an SCTP association with the 3053 remote M3UA peer by sending an SCTP-ASSOCIATE primitive to the local 3054 SCTP layer. 3056 When an SCTP association has been successfully established, the SCTP 3057 will send an SCTP-COMMUNICATION_UP notification primitive to the local 3058 M3UA layer. At the SGP or IPSP that initiated the request, the M3UA 3059 layer will send an M-SCTP_ESTABLISH confirm primitive to Layer 3060 Management when the association set-up is complete. At the peer M3UA 3061 layer, an M-SCTP_ESTABLISH indication primitive is sent to Layer 3062 Management upon successful completion of an incoming SCTP association 3063 set-up. 3065 An M-SCTP_RELEASE request primitive from Layer Management initates the 3066 tear-down of an SCTP association. The M3UA layer accomplishes a 3067 graceful shutdown of the SCTP association by sending an SCTP-SHUTDOWN 3068 primitive to the SCTP layer. 3070 When the graceful shutdown of the SCTP association has been 3071 accomplished, the SCTP layer returns an SCTP-SHUTDOWN_COMPLETE 3072 notification primitive to the local M3UA layer. At the M3UA Layer that 3073 initiated the request, the M3UA layer will send an M-SCTP_RELEASE 3074 confirm primitive to Layer Management when the association teardown is 3075 complete. At the peer M3UA Layer, an M-SCTP_RELEASE indication 3076 primitive is sent to Layer Management upon successful tear-down of an 3077 SCTP association. 3079 An M-SCTP_STATUS request primitive supports a Layer Management query of 3080 the local status of a particular SCTP association. The M3UA layer 3081 simply maps the M-SCTP_STATUS request primitive to an SCTP-STATUS 3082 primitive to the SCTP layer. When the SCTP responds, the M3UA layer 3083 maps the association status information to an M-SCTP_STATUS confirm 3084 primitive. No peer protocol is invoked. 3086 Similar LM-to-M3UA-to-SCTP and/or SCTP-to-M3UA-to-LM primitive mappings 3087 can be described for the various other SCTP Upper Layer primitives in 3088 RFC2960 [13] such as INITIALIZE, SET PRIMARY, CHANGE HEARTBEAT, 3089 REQUEST HEARTBEAT, GET SRTT REPORT, SET FAILURE THRESHOLD, SET PROTOCOL 3090 PARAMETERS, DESTROY SCTP INSTANCE, SEND FAILURE, AND NETWORK STATUS 3091 CHANGE. Alternatively, these SCTP Upper Layer primitives (and Status 3092 as well) can be considered for modeling purposes as a Layer Management 3093 interaction directly with the SCTP Layer. 3095 M-NOTIFY indication and M-ERROR indication primitives indicate to Layer 3096 Management the notification or error information contained in a 3097 received M3UA Notify or Error message respectively. These indications 3098 can also be generated based on local M3UA events. 3100 An M-ASP_STATUS request primitive supports a Layer Management query of 3101 the status of a particular local or remote ASP. The M3UA layer 3102 responds with the status in an M-ASP_STATUS confirm primitive. No M3UA 3103 peer protocol is invoked. 3105 An M-AS_STATUS request supports a Layer Management query of the status 3106 of a particular AS. The M3UA responds with an M-AS_STATUS confirm 3107 primitive. No M3UA peer protocol is invoked. 3109 M-ASP_UP request, M-ASP_DOWN request, M-ASP_ACTIVE request and M-ASP_ 3110 INACTIVE request primitives allow Layer Management at an ASP to 3111 initiate state changes. Upon successful completion, a corresponding 3112 confirm primitive is provided by the M3UA layer to Layer Management. 3113 If an invocation is unsuccessful, an Error indication primitive is 3114 provided in the primitive. 3116 These requests result in outgoing ASP Up, ASP Down, ASP Active and 3117 ASP Inactive messages to the remote M3UA peer at an SGP or IPSP. 3119 4.1.3 Receipt of M3UA Peer Management Messages 3121 Upon successful state changes resulting from reception of ASP Up, 3122 ASP Down, ASP Active and ASP Inactive messages from a peer M3UA, the 3123 M3UA layer SHOULD invoke corresponding M-ASP_UP, M-ASP_DOWN, M- 3124 ASP_ACTIVE and M-ASP_INACTIVE, M-AS_ACTIVE, M-AS_INACTIVE, and M- 3125 AS_DOWN indication primitives to the local Layer Management. 3127 M-NOTIFY indication and M-ERROR indication primitives indicate to Layer 3128 Management the notification or error information contained in a 3129 received M3UA Notify or Error message. These indications can also be 3130 generated based on local M3UA events. 3132 4.2 Procedures to Support the Management of SCTP Associations with M3UA 3133 Peers 3135 These procedures support the M3UA management of SCTP Associations 3136 between SGPs and ASPs or between IPSPs. 3138 4.2.1 AS and ASP State Maintenance 3140 The M3UA layer on the SGP maintains the state of each remote ASP, in 3141 each Application Server that the ASP is configured to receive traffic, 3142 as input to the M3UA message distribution function. Similarly, where 3143 IPSPs use M3UA in a point-to-point fashion, the M3UA layer in an IPSP 3144 maintains the state of remote IPSPs. For the purposes of the following 3145 procedures, only the SGP/ASP case is described but the SGP side of the 3146 procedures also apply to an IPSP sending traffic to an AS consisting of 3147 a set of remote IPSPs. 3149 4.2.1.1 ASP States 3151 The state of each remote ASP, in each AS that it is configured to 3152 operate, is maintained in the M3UA layer in the SGP. The state of a 3153 particular ASP in a particular AS changes due to events. The events 3154 include: 3156 * Reception of messages from the peer M3UA layer at the ASP; 3157 * Reception of some messages from the peer M3UA layer at other ASPs 3158 in the AS (e.g., ASP Active message indicating "Over-ride"); 3159 * Reception of indications from the SCTP layer; or 3160 * Local Management intervention. 3162 The ASP state transition diagram is shown in Figure 4. The possible 3163 states of an ASP are: 3165 ASP-DOWN: The remote M3UA peer at the ASP is unavailable and/or the 3166 related SCTP association is down. Initially all ASPs will be in this 3167 state. An ASP in this state SHOULD NOT be sent any M3UA messages. 3169 ASP-INACTIVE: The remote M3UA peer at the ASP is available (and the 3170 related SCTP association is up) but application traffic is stopped. In 3171 this state the ASP MAY be sent any non-DATA M3UA messages. 3173 ASP-ACTIVE: The remote M3UA peer at the ASP is available and 3174 application traffic is active (for a particular Routing Context or set 3175 of Routing Contexts). 3177 ASP-STANDBY: The remote M3UA peer at the ASP is available and ready to 3178 receive application traffic at any time (for a particular Routing 3179 Context or set of Routing Contexts). In this state the ASP MAY be sent 3180 any non-Data M3UA messages. 3182 Figure 4: ASP State Transition Diagram 3184 +--------------+ 3185 | ASP-ACTIVE | 3186 +----------------------| or | 3187 | Other +-------| ASP-STANDBY* | 3188 | ASP in AS | +--------------+ 3189 | Overrides | ^ | 3190 | | ASP | | ASP 3191 | | Active | | Inactive 3192 | | | v 3193 | | +--------------+ 3194 | | | | 3195 | +------>| ASP-INACTIVE | 3196 | +--------------+ 3197 | ^ | 3198 ASP Down/ | ASP | | ASP Down / 3199 SCTP CDI | Up | | SCTP CDI 3200 | | v 3201 | +--------------+ 3202 | | | 3203 +--------------------->| ASP-DOWN | 3204 | | 3205 +--------------+ 3207 *Note: ASP-ACTIVE and ASP-STANDBY differ only in whether the ASP is 3208 currently receiving Data traffic within the AS. 3210 SCTP CDI: The SCTP CDI denotes the local SCTP layer's Communication 3211 Down Indication to the Upper Layer Protocol (M3UA) on an SGP. The local 3212 SCTP layer will send this indication when it detects the loss of 3213 connectivity to the ASP's peer SCTP layer. SCTP CDI is understood as 3214 either a SHUTDOWN_COMPLETE notification or COMMUNICATION_LOST 3215 notification from the SCTP layer. 3217 4.2.1.2 AS States 3219 The state of the AS is maintained in the M3UA layer on the SGP. The 3220 state of an AS changes due to events. These events include: 3222 * ASP state transitions 3223 * Recovery timer triggers 3225 The possible states of an AS are: 3227 AS-DOWN: The Application Server is unavailable. This state implies 3228 that all related ASPs are in the ASP-DOWN state for this AS. Initially 3229 the AS will be in this state. An Application Server MUST be in the AS- 3230 DOWN state before it can be removed from a configuration. 3232 AS-INACTIVE: The Application Server is available but no application 3233 traffic is active (i.e., one or more related ASPs are in the ASP- 3234 INACTIVE state, but none in the ASP-ACTIVE or ASP-STANDBY states). The 3235 recovery timer 3236 T(r) is not running or has expired. 3238 AS-ACTIVE: The Application Server is available and application traffic 3239 is active. This state implies that at least one ASP is in the ASP- 3240 ACTIVE state. 3242 AS-PENDING: An active ASP has transitioned to ASP-INACTIVE or ASP-DOWN 3243 and it was the last remaining active ASP in the AS (and no ASPs in the 3244 ASP-STANDBY state are available. A recovery timer T(r) SHOULD be 3245 started and all incoming signalling messages SHOULD be queued by the 3246 SGP. If an ASP becomes ASP-ACTIVE before T(r) expires, the AS is moved 3247 to the AS-ACTIVE state and all the queued messages will be 3248 sent to the ASP. 3250 If T(r) expires before an ASP becomes ASP-ACTIVE, the SGP stops queuing 3251 messages and discards all previously queued messages. The AS will move 3252 to the AS-INACTIVE state if at least one ASP is in ASP-INACTIVE state, 3253 otherwise it will move to AS-DOWN state. 3255 Figure 5 shows an example AS state machine for the case where the 3256 AS/ASP data is pre-configured. For other cases where the AS/ASP 3257 configuration data is created dynamically, there would be differences 3258 in the state machine, especially at creation of the AS. 3260 For example, where the AS/ASP configuration data is not created until 3261 Registration of the first ASP, the AS-INACTIVE state is entered 3262 directly upon the first successful REG REQ from an ASP. Another 3263 example is where the AS/ASP configuration data is not created until the 3264 first ASP successfully enters the ASP-ACTIVE state. In this case the 3265 AS-ACTIVE state is entered directly. 3267 Figure 5: AS State Transition Diagram 3269 +----------+ one ASP trans to ACTIVE +-------------+ 3270 | AS- |---------------------------->| AS- | 3271 | INACTIVE | | ACTIVE | 3272 | |<--- | | 3273 +----------+ \ +-------------+ 3274 ^ | \ Tr Expiry, ^ | 3275 | | \ at least one | | 3276 | | \ ASP in ASP-INACTIVE | | 3277 | | \ | | 3278 | | \ | | 3279 | | \ | | 3280 one ASP | | all ASP \ one ASP | | Last ACTIVE 3281 trans | | trans to \ trans to | | ASP trans to 3282 to | | ASP-DOWN -------\ ASP- | | ASP-INACTIVE 3283 ASP- | | \ ACTIVE | | or ASP-DOWN 3284 INACTIVE| | \ | | 3285 | | \ | | 3286 | | \ | | 3287 | v \ | v 3288 +----------+ \ +-------------+ 3289 | | --| | 3290 | AS-DOWN | | AS-PENDING | 3291 | | | (queueing) | 3292 | |<----------------------------| | 3293 +----------+ Tr Expiry (no ASP +-------------+ 3294 in ASP-INACTIVE state) 3296 Tr = Recovery Timer 3298 4.2.2 M3UA Management Procedures for Primitives 3300 Before the establishment of an SCTP association the ASP state at both 3301 the SGP and ASP is assumed to be in the state ASP-DOWN. 3303 Once the SCTP association is established (see Section 4.1.2) and 3304 assuming that the local M3UA-User is ready, the local M3UA ASP 3305 Maintenance (ASPM) function will initiate the relevant procedures, 3306 using the ASP Up/ASP Down/ASP Active/ASP Inactive messages to convey 3307 the ASP state to the SGP (see Section 4.3.3). 3309 If the M3UA layer subsequently receives an SCTP-COMMUNICATION_DOWN 3310 or SCTP-RESTART indication primitive from the underlying SCTP layer, it 3311 will inform the Layer Management by invoking the M-SCTP_STATUS 3312 indication primitive. The state of the ASP will be moved to ASP-DOWN 3313 At an ASP, the MTP3-User will be informed of the unavailability of any 3314 affected SS7 destinations through the use of MTP-PAUSE indication 3315 primitives. In the case 3316 of SS7 network isolation, the local MTP3-Users MAY be informed by 3317 implementation-dependent means, as there is currently no primitive 3318 defined for conveying this information. 3320 In the case of SCTP-COMMUNICATION_DOWN, the SCTP client MAY try to re- 3321 establish the SCTP Association. This MAY be done by the M3UA layer 3322 automatically, or Layer Management MAY re-establish using the M- 3323 SCTP_ESTABLISH request primitive. 3325 In the case of an SCTP-RESTART indication at an ASP, the ASP is now 3326 considered by its M3UA peer to be in the ASP-DOWN state. The ASP, if 3327 it is to recover, must begin any recovery with the ASP-Up procedure. 3329 4.2.3 M3UA Management Procedures for Peer-to-Peer Messages 3331 All M3UA Management and ASP State and Traffic Maintenance messages are 3332 sent on a sequenced 3333 stream to ensure ordering. SCTP stream '0' is used. 3335 4.2.3.1 ASP Up Procedures 3337 After an ASP has successfully established an SCTP association to an 3338 SGP, the SGP waits for the ASP to send an ASP Up message, indicating 3339 that the ASP M3UA peer is available. The ASP is always the initiator 3340 of the ASP Up message. This action MAY be initiated at the ASP by an 3341 M-ASP_UP request primitive from Layer Management or MAY be initiated 3342 automatically by an M3UA management function. 3344 When an ASP Up message is received at an SGP and internally the remote 3345 ASP is in the ASP-DOWN state and not considered locked-out for local 3346 management reasons, the SGP marks the remote ASP in the state ASP- 3347 INACTIVE and informs Layer Management with an M-ASP_Up indication 3348 primitive. If the SGP is aware, via current configuration data, which 3349 Application Servers the ASP is configured to operate in, the SGP 3350 updates the ASP state to ASP-INACTIVE in each AS that it is a member. 3351 Alternatively, the SGP may move the ASP into a pool of Inactive ASPs 3352 available for future configuration within Application Server(s), 3353 determined in a subsequent Registration Request or ASP Active 3354 procedure. The SGP responds with an ASP Up Ack message in 3355 acknowledgement. The SGP sends an ASP Up Ack message in response to a 3356 received ASP Up message even if the ASP is already marked as ASP- 3357 INACTIVE at the SGP. 3359 If for any local reason (e.g., management lock-out) the SGP cannot 3360 respond with an ASP Up Ack message, the SGP responds to an ASP Up 3361 message with an Error message with Reason "Refused - Management 3362 Blocking". 3364 At the ASP, the ASP Up Ack message received is not acknowledged. Layer 3365 Management is informed with an M-ASP_UP confirm primitive. When an ASP 3366 enters the ASP-Inactive state from the ASP_Down state towards an SGP 3367 the M3UA MUST mark all SS7 destinations configured to be reachable via 3368 this SGP as available. 3370 When the ASP sends an ASP Up message it starts timer T(ack). If the 3371 ASP does not receive a response to an ASP Up message within T(ack), the 3372 ASP MAY restart T(ack) and resend ASP-Up messages until it receives an 3373 ASP Up Ack message. T(ack) is provisionable, with a default of 2 3374 seconds. Alternatively, retransmission of ASP Up messages MAY be put 3375 under control of Layer Management. In this method, expiry of T(ack) 3376 results in an M-ASP_UP confirm primitive carrying a negative 3377 indication. 3379 The ASP must wait for the ASP Up Ack message before sending any other 3380 M3UA messages (e.g., ASP Active or REG REQ). If the SGP receives any 3381 other M3UA messages before an ASP Up message is received, the SGP 3382 SHOULD discard them. 3384 If an ASP Up message is received and internally the remote ASP is in 3385 the ASP-ACTIVE or ASP-STANDBY state, an ASP-Up Ack message is returned, 3386 as well as an Error message ("Unexpected Message), and the remote ASP 3387 state is changed to ASP-INACTIVE in all relevant Application Servers. 3389 If an ASP Up message is received and internally the remote ASP is 3390 already in the ASP-INACTIVE state, an ASP Up Ack message is returned 3391 and no further action is taken. 3393 4.2.3.1.1 M3UA Version Control 3395 If an ASP Up message with an unsupported version is received, the 3396 receiving end responds with an Error message, indicating the version 3397 the receiving node supports and notifies Layer Management. 3399 This is useful when protocol version upgrades are being performed in a 3400 network. A node upgraded to a newer version should support the older 3401 versions used on other nodes it is communicating with. Because ASPs 3402 initiate the ASP Up procedure it is assumed that the Error message 3403 would normally come from the SGP. 3405 4.2.3.1.2 IPSP Considerations 3407 In the case of peer-to-peer IPSPs, either of the IPSPs (IPSP_A) may 3408 start operations by sending an ASP Up message to the remote peer 3409 (IPSP_B). When the ASP Up message is received at IPSP_B and internally 3410 the remote IPSP_A is in the ASP-DOWN state and not considered locked- 3411 out for local management reasons, IPSP_B marks the remote IPSP_A in the 3412 state ASP-INACTIVE and informs Layer Management with an M-ASP_Up 3413 indication primitive. IPSP_B returns an ASP-Up Ack message to IPSP_A. 3414 IPSP_A moves IPSP_B to the ASP-INACTIVE state upon reception of an ASP 3415 Up Ack message, if is not already in the ASP_INACTIVE state, and 3416 informs Layer Management with an M-ASP_UP confirmation primitive. 3418 If for any local reason (e.g., management lock-out) the IPSP_B cannot 3419 respond with an ASP Up Ack message, it responds to an ASP Up message 3420 with an Error message with Reason "Refused - Management Blocking" and 3421 leaves IPSP_A in the ASP-DOWN state. 3423 4.2.3.2 ASP-Down Procedures 3425 The ASP will send an ASP Down message to an SGP when the ASP wishes to 3426 be 3427 removed from service in all Application Servers that it is a member and 3428 no longer receive any DATA, SSNM or ASPTM messages. This action MAY be 3429 initiated at the ASP by an M-ASP_DOWN request primitive from Layer 3430 Management or MAY be initiated automatically by an M3UA management 3431 function. 3433 Whether the ASP is permanently removed from any AS is a function of 3434 configuration management. In the case where the ASP previously used 3435 the Registration procedures (see Section 3.5.5) to register within 3436 Application Servers but has not deregistered from all of them prior to 3437 sending the ASP Down message, the SGP SHOULD consider the ASP as 3438 Deregistered in all Application Servers that it is still a member. 3440 The SGP marks the ASP as ASP-DOWN, informs Layer Management with an M- 3441 ASP_Down indication primitive, and returns an ASP Down Ack message to 3442 the ASP. has locked out the ASP for management reasons. 3444 The SGP sends an ASP Down Ack message in response to a received ASP- 3445 Down message from the ASP even if the ASP is already marked as ASP-DOWN 3446 at the SGP. The SGP sends an ASP Down Ack message even if the reason 3447 in the received ASP Down message is considered invalid. 3449 At the ASP, the ASP Down Ack message received is not acknowledged. 3450 Layer Management is informed with an M-ASP_DOWN confirm primitive. If 3451 the ASP receives an ASP Down Ack without having sent an ASP Down 3452 message, the ASP should now consider itself as in the ASP-DOWN state. 3453 If the ASP was previously in the ASP-ACTIVE or ASP_INACTIVE state, the 3454 ASP should then initiate procedures to return itself to its previous 3455 state. 3457 When the ASP sends an ASP Down message it starts timer T(ack). If the 3458 ASP does not receive a response to an ASP Down message within T(ack), 3459 the ASP MAY restart T(ack) and resend ASP Down messages until it 3460 receives an ASP Down Ack message. T(ack) is provisionable, with a 3461 default of 2 seconds. Alternatively, retransmission of ASP Down 3462 messages MAY be put under control of Layer Management. In this method, 3463 expiry of T(ack) results in an M-ASP_DOWN confirm primitive carrying a 3464 negative indication. 3466 4.2.3.4 ASP-Active Procedures 3468 Anytime after the ASP has received an ASP Up Ack message from the SGP 3469 or IPSP, the ASP sends an ASP Active message to the SGP indicating that 3470 the ASP is ready to start processing traffic. This action MAY be 3471 initiated at the ASP by an M-ASP_ACTIVE request primitive from Layer 3472 Management or MAY be initiated automatically by an M3UA management 3473 function. In the case where an ASP wishes to process the traffic for 3474 more than one Application Server across a common SCTP association, the 3475 ASP Active message(s) SHOULD contain a list of one or more Routing 3476 Contexts to indicate for which Application Servers the ASP Active 3477 message applies. It is not necessary for the ASP to include all Routing 3478 Contexts of interest in a single ASP Active message, thus requesting to 3479 become active in all Routing Contexts at the same time. Multiple ASP 3480 Active messages MAY be used to activate within the Application Servers 3481 independently, or in sets. In the case where an ASP Active message 3482 does not contain a Routing Context parameter, the receiver must know, 3483 via configuration data, which Application Server(s) the ASP is a 3484 member. 3486 For the Application Servers that the ASP can be successfully activated, 3487 he SGP or IPSP responds 3488 with one or more ASP Active Ack messages, including the associated 3489 Routing Context and Traffic Mode Type values. The Routing Context 3490 parameter MUST be included in the Asp Active Ack message if the 3491 received ASP Active message contained any Routing Contexts. Depending 3492 on the ASP Active Message Traffic Mode Type request, the SGP moves the 3493 ASP to the correct ASP traffic state within the associated Application 3494 Server(s). Layer Management is informed with an M-ASP_Active 3495 indication. If the SGP or IPSP receives any Data messages before an ASP 3496 Active message is received, the SGP or IPSP MAY discard them. By 3497 sending an ASP Active Ack message, the SGP or IPSP is now ready to 3498 receive and send traffic for the related Routing Context(s). The ASP 3499 SHOULD NOT send Data messages for the related Routing Context(s) before 3500 receiving an ASP Active Ack message, or it will risk message loss. 3502 Multiple ASP Active Ack messages MAY be used in response to an ASP 3503 Active message containing multiple Routing Contexts, allowing the SGP 3504 or IPSP to independently acknowledge the ASP Active message for 3505 different (sets of) Routing Contexts. The SGP or IPSP sends an Error 3506 message ("Invalid Routing Context") for each Routing Context value that 3507 the ASP cannot be successfully activated . 3509 In the case where an "out-of-the-blue" ASP Active message is received 3510 (i.e., the ASP has not registered with the SG or the SG has no static 3511 configuration data for the ASP), the message may be silently discarded. 3513 The SGP MUST send an ASP Active Ack message in response to a received 3514 ASP Active message from the ASP, if the ASP is already marked in the 3515 ASP-ACTIVE state at the SGP. 3517 At the ASP, the ASP Active Ack message received is not acknowledged. 3518 Layer Management is informed with an M-ASP_ACTIVE confirm primitive. 3519 It is possible for the ASP to receive Data message(s) before the ASP 3520 Active Ack message as the ASP Active Ack and Data messages from an SG 3521 or IPSP may be sent on different SCTP streams. Message loss is 3522 possible as the ASP does not consider itself in the ASP-ACTIVE state 3523 until reception of the ASP Active Ack message. 3525 When the ASP sends an ASP Active message it starts timer T(ack). If 3526 the ASP does not receive a response to an ASP Active message within 3527 T(ack), the ASP MAY restart T(ack) and resend ASP Active messages until 3528 it receives an ASP Active Ack message. T(ack) is provisionable, with a 3529 default of 2 seconds. Alternatively, retransmission of ASP Active 3530 messages MAY be put under control of Layer Management. In this method, 3531 expiry of T(ack) results in an M-ASP_ACTIVE confirm primitive carrying 3532 a negative indication. 3534 There are four modes of Application Server traffic handling in the SGP 3535 M3UA layer - Over-ride, Over-ride (Standby), Load-share and Load-share 3536 (Standby). The Traffic Mode Type parameter in the ASP Active message 3537 indicates the traffic handling mode used in a particular Application 3538 Server. If the SGP determines that the mode indicated in an ASP Active 3539 message is unsupported or incompatible with the mode currently 3540 configured for the AS, the SGP responds with an Error message 3541 ("Unsupported / Invalid Traffic Handling Mode"). If the Traffic 3542 Handling mode of the Application Server is not already known via 3543 configuration data, then the Traffic Handling mode indicated in the 3544 first ASP Active message causing the transition of the Application 3545 Server state to AS-ACTIVE MAY be used to set the mode. 3547 In the case of an Over-ride mode AS, reception of an ASP Active message 3548 at an SGP causes the (re)direction of all traffic for the AS to the ASP 3549 that sent the ASP Active message. Any previously active ASP in the AS 3550 is now considered to be in state ASP-INACTIVE and SHOULD no longer 3551 receive traffic from the SGP within the AS. The SGP or IPSP then MUST 3552 send a Notify message ("Alternate ASP-Active") to the previously active 3553 ASP in the AS, and SHOULD stop traffic to/from that ASP. The ASP 3554 receiving this Notify MUST consider itself now in the ASP-INACTIVE 3555 state, if it is not already aware of this via inter-ASP communication 3556 with the Over-riding ASP. 3558 In the case of Over-ride (Standby) mode the traffic is not started to 3559 the ASP until the currently active ASP transitions to the ASP-INACTIVE 3560 or ASP-DOWN state. At this point the ASP that sent the ASP Active 3561 message ("Over-Ride (Standby)") is moved to the ASP-ACTIVE state and 3562 the traffic is redirected. A second ASP Active Ack message with a new 3563 Traffic Mode Type ("Over-ride", previously "Over-ride(Standby)") is 3564 sent to the ASP. A Notify message ("Alternate ASP-Active") is not sent 3565 in this case. 3567 If there is no currently active ASP, an ASP Active Ack message ("Over- 3568 ride") is returned right away and the traffic is directed to the ASP. 3570 In the case of a Load-share mode AS, reception of an ASP Active message 3571 at an SGP or IPSP causes the direction of traffic to the ASP sending 3572 the ASP Active message, in addition to all the other ASPs that are 3573 currently active in the AS. The algorithm at the SGP for load-sharing 3574 traffic within an AS to all the active ASPs is implementation 3575 dependent. The algorithm could, for example, be round-robin or based 3576 on information in the Data message (e.g., the SLS, SCCP SSN, ISUP CIC 3577 value). 3579 An SGP or IPSP, upon reception of an ASP Active message for the first 3580 ASP in a Loadshare AS, MAY choose not to direct traffic to a newly 3581 active ASP until it determines that there are sufficient resources to 3582 handle the expected load (e.g., until there are "n" ASPs in state ASP- 3583 ACTIVE in the AS). 3585 In the case of a Load-share (Standby) mode AS, the traffic is not 3586 started to the ASP until the SGP or IPSP determines that there are 3587 insufficient resources available in the AS. This is likely when one of 3588 the active load-sharing ASPs transitions to either the ASP-INACTIVE or 3589 ASP-DOWN state. At this point the ASP that sent the ASP Active message 3590 ("Load-share (Standby)") is moved to the ASP_ACTIVE state and traffic 3591 is started. A second ASP Active Ack message with a new Traffic Mode 3592 Type ("Load-share" - previously "Loadshare(Standby)") is sent to the 3593 ASP. A Notify message ("Insufficient ASP resources active in AS ") is 3594 not sent in this case. 3596 If there is no currently active ASP, an ASP Active Ack message 3597 ("Loadshare") is returned right away and the traffic is directed to the 3598 ASP. 3600 All ASPs within a load-sharing mode AS must be able to process any 3601 Data message received for the AS, in order to accommodate any potential 3602 fail-over or rebalancing of the offered load. 3604 4.2.3.5 ASP Inactive Procedures 3606 When an ASP wishes to withdraw from receiving traffic within an AS, the 3607 ASP sends an ASP Inactive message to the SGP or IPSP. This action MAY 3608 be initiated at the ASP by an M-ASP_INACTIVE request primitive from 3609 Layer Management or MAY be initiated automatically by an M3UA 3610 management function. In the case where an ASP is processing the 3611 traffic for more than one Application Server across a common SCTP 3612 association, the ASP Inactive message contains one or more Routing 3613 Contexts to indicate for which Application Servers the ASP Inactive 3614 message applies. In the case where an ASP Inactive message does not 3615 contain a Routing Context parameter, the receiver must know, via 3616 configuration data, which Application Servers the ASP is a member and 3617 move the ASP to the ASP-INACTIVE state in each all Application Servers. 3618 In the case of an Over-ride mode AS, where another ASP has already 3619 taken over the traffic within the AS with an ASP Active ("Over-ride") 3620 message, the ASP that sends the ASP Inactive message is already 3621 considered by the SGP to be in state ASP-INACTIVE. .An ASP Inactive Ack 3622 message is sent to the ASP, after ensuring that all traffic is stopped 3623 to the ASP. 3625 In the case of a Load-share mode AS, the SGP moves the ASP to the ASP- 3626 INACTIVE state and the AS traffic is re-allocated across the remaining 3627 ASPs in the state ASP-ACTIVE, as per the load-sharing algorithm 3628 currently used within the AS. A Notify message("Insufficient ASP 3629 resources active in AS") MAY be sent to all inactive ASPs, if required. 3630 However, if a Loadshare ("Standby") ASP is available, it may be now 3631 immediately included in the loadshare group and a Notify message is not 3632 sent. An ASP Inactive Ack message is sent to the ASP after all traffic 3633 is halted and Layer Management is informed with an M-ASP_INACTIVE 3634 indication primitive. 3636 Multiple ASP Inactive Ack messages MAY be used in response to an ASP 3637 Inactive message containing multiple Routing Contexts, allowing the SGP 3638 or IPSP to independently acknowledge for different (sets of) Routing 3639 Contexts. The SGP or IPSP sends an Error message ("Invalid Routing 3640 Context") message for each invalid or un-configured Routing Context 3641 value in a received ASP Inactive message message. 3643 The SGP MUST send an ASP Inactive Ack message in response to a received 3644 ASP Inactive message from the ASP and the ASP is already marked as ASP- 3645 INACTIVE at the SGP. 3647 At the ASP, the ASP-Inactive Ack message received is not acknowledged. 3648 Layer Management is informed with an M-ASP_INACTIVE confirm primitive. 3649 When the ASP sends an ASP Inactive message it starts timer T(ack). If 3650 the ASP does not receive a response to an ASP Inactive message within 3651 T(ack), the ASP MAY restart T(ack) and resend ASP Inactive messages 3652 until it receives an ASP Inactive Ack message. T(ack) is 3653 provisionable, with a default of 2 seconds. Alternatively, 3654 retransmission of ASP Inactive messages MAY be put under control of 3655 Layer Management. In this method, expiry of T(ack) results in a M- 3656 ASP_Inactive confirm primitive carrying a negative indication. 3658 If no other ASPs in the Application Server are in the state ASP-ACTIVE 3659 or ASP-STANDBY, the SGP MUST send a Notify message ("AS-Pending") to 3660 all of the ASPs in the AS which are in the state ASP-INACTIVE. The SGP 3661 SHOULD start buffering the incoming messages for T(r)seconds, after 3662 which messages MAY be discarded. T(r) is configurable by the network 3663 operator. If the SGP receives an ASP Active message from an ASP in the 3664 AS before expiry of T(r), the buffered traffic is directed to that ASP 3665 and the timer is cancelled. If T(r) expires, the AS is moved to the 3666 AS-INACTIVE state. 3668 4.2.3.6 Notify Procedures 3670 A Notify message reflecting a change in the AS state SHOULD be sent to 3671 all ASPs in the AS, except those in the ASP-DOWN state, with 3672 appropriate Status Information. The Notify message MUST be sent after 3673 any ASP State or Traffic Management acknowledgement messages (e.g., ASP 3674 Up Ack, ASP Down Ack, ASP Active Ack, or ASP Inactive Ack). At the 3675 ASP, Layer Management is informed with an M-NOTIFY indication 3676 primitive. 3678 In the case where a Notify message("AS-Pending") message is sent by an 3679 SGP that now has no ASPs active to service the traffic, or where a 3680 Notify message("Insufficient ASP resources active in AS") is sent in 3681 the Loadshare mode, the Notify message does not explicitly compel the 3682 ASP(s) receiving the message to become active. The ASPs remain in 3683 control of what (and when) traffic action is taken. 3685 In the case where a Notify message does not contain a Routing Context 3686 parameter, the receiver must know, via configuration data, of which 3687 Application Servers the ASP is a member and take the appropriate action for 3688 the ASP in each AS. 3690 4.2.3.7 Heartbeat Procedures 3692 The optional Heartbeat procedures MAY be used when operating over 3693 transport layers that do not have their own heartbeat mechanism for 3694 detecting loss of the transport association (i.e., other than SCTP). 3696 After receiving an ASP Up Ack message from an M3UA peer in response to 3697 an ASP Up message, an ASP may optionally send Heartbeat messages 3698 periodically, subject to a provisionable timer T(beat). Upon receiving 3699 a Heartbeat message, the M3UA peer MUST respond with a Heartbeat ACK 3700 message. 3702 At the ASP, if no Heartbeat Ack message (or any other M3UA message) is 3703 received from the M3UA peer within 2*T(beat), the remote M3UA peer is 3704 considered unavailable. Transmission of Heartbeat messages is stopped 3705 and the ASP SHOULD attempt to re-establish communication with the SGP 3706 M3UA peer. 3708 The Heartbeat message may optionally contain an opaque Heartbeat Data 3709 parameter that MUST be echoed back unchanged in the related Heartbeat 3710 Ack message. The ASP, upon examining the contents of the returned 3711 Heartbeat Ack message, MAY choose to consider the remote M3UA peer as 3712 unavailable. The contents/format of the Heartbeat Data parameter is 3713 implementation-dependent and only of local interest to the original 3714 sender. The contents may be used, for example, to support a Heartbeat 3715 sequence algorithm (to detect missing Heartbeats), and/or a timestamp 3716 mechanism (to evaluate delays). 3718 Note: Heartbeat related events are not shown in Figure 4 "ASP state 3719 transition diagram". 3721 4.2.4 Routing Key Management Procedures 3723 4.2.4.1 Registration 3725 An ASP MAY dynamically register with an SGP as an ASP within an 3726 Application Server using the REG REQ message. A Routing Key parameter 3727 in the REG REQ message specifies the parameters associated with the 3728 Routing Key. 3730 The SGP examines the contents of the received Routing Key parameter and 3731 compares it with the currently provisioned Routing Keys. If the 3732 received Routing Key matches an existing SGP Routing Key entry, and the 3733 ASP is not currently included in the list of ASPs for the related 3734 Application Server, the SGP MAY authorize the ASP to be added to the 3735 AS. Or, if the Routing Key does not currently exist and the received 3736 Routing Key data is valid and unique, an SGP supporting dynamic 3737 configuration MAY authorize the creation of a new Routing Key and 3738 related Application Server and add the ASP to the new AS. In either 3739 case, the SGP returns a Registration Response message to the ASP, 3740 containing the same Local-RK-Identifier as provided in the initial 3741 request, and a Registration Result "Successfully Registered". A unique 3742 Routing Context value assigned to the SGP Routing Key is included. The 3743 method of Routing Context value assignment at the SG/SGP is 3744 implementation dependent but must be guaranteed to be unique across all 3745 SGPs in an SG. 3747 If the SGP determines that the received Routing Key data is invalid, or 3748 contains invalid parameter values, the SGP returns a Registration 3749 Response message to the ASP, containing a Registration Result "Error - 3750 Invalid Routing Key", "Error - Invalid DPC", "Error - Invalid Network 3751 Appearance" as appropriate. 3753 If the SGP determines that a unique Routing Key cannot be created, the 3754 SGP returns a Registration Response message to the ASP, with a 3755 Registration Status of "Error - "Cannot Support Unique Routing" An 3756 incoming signalling message received at an SGP should not match against 3757 more than one Routing Key. 3759 If the SGP does not authorize the registration request, the SGP returns 3760 a REG RSP message to the ASP containing the Registration Result "Error 3761 � Permission Denied". 3763 If an SGP determines that a received Routing Key does not currently 3764 exist and the SGP does not support dynamic configuration, the SGP 3765 returns a Registration Response message to the ASP, containing a 3766 Registration Result "Error - Routing Key not Currently Provisioned". 3768 If an SGP determines that a received Routing Key does not currently 3769 exist and the SGP supports dynamic configuration but does not have the 3770 capacity to add new Routing Key and Application Server entries, the SGP 3771 returns a Registration Response message to the ASP, containing a 3772 Registration Result "Error - Insufficient Resources". 3774 If an SGP determines that one or more of the Routing Key parameters are 3775 not supported for the purpose of creating new Routing Key entries, the 3776 SGP returns a Registration Response message to the ASP, containing a 3777 Registration Result "Error � Unsupported RK parameter field". This 3778 result MAY be used if, for example, the SGP does not support RK Circuit 3779 Range Lists in a Routing Key because the SGP does not support ISUP 3780 traffic, or does not provide CIC range granularity. 3782 A Registration Response "Error � Unsupported Traffic Handling Mode" is 3783 returned if the Routing Key in the REG REQ contains an Traffic Handling 3784 Mode that is inconsistent with the presently configured mode for the 3785 matching Application Server. 3786 An ASP MAY register multiple Routing Keys at once by including a number 3787 of Routing Key parameters in a single REG REQ message. The SGP MAY 3788 respond to each registration request in a single REG RSP message, 3789 indicating the success or failure result for each Routing Key in a 3790 separate Registration Result parameter. Alternatively the SGP MAY 3791 respond with multiple REG RSP messages, each with one or more 3792 Registration Result parameters. The ASP uses the Local-RK-Identifier 3793 parameter to correlate the requests with the responses. 3795 Upon successful registration of an ASP in an AS, the SGP can now send 3796 related SS7 Signalling Network Management messaging, if this did not 3797 previously start upon the ASP transitioning to state ASP-INACTIVE 3799 4.2.4.2 Deregistration 3801 An ASP MAY dynamically deregister with an SGP as an ASP within an 3802 Application Server using the DEREG REQ message. A Routing Context 3803 parameter in the DEREG REQ message specifies which Routing Keys to de- 3804 register. An ASP SHOULD move to the ASP-INACTIVE state for an 3805 Application Server before attempting to deregister the Routing Key 3806 (i.e., deregister after receiving an ASP Inactive Ack). Also, an ASP 3807 SHOULD deregister from all Application Servers that it is a member 3808 before attempting to move to the ASP-Down state. 3810 The SGP examines the contents of the received Routing Context parameter 3811 and validates that the ASP is currently registered in the Application 3812 Server(s) related to the included Routing Context(s). If validated, 3813 the ASP is de-registered as an ASP in the related Application Server. 3815 The deregistration procedure does not necessarily imply the deletion of 3816 Routing Key and Application Server configuration data at the SGP. Other 3817 ASPs may continue to be associated with the Application Server, in 3818 which case the Routing Key data MUST NOT be deleted. If a 3819 Deregistration results in no more ASPs in an Application Server, an SGP 3820 MAY delete the Routing Key data. 3822 The SGP acknowledges the deregistration request by returning a DEREG 3823 RSP message to the requesting ASP. The result of the deregistration is 3824 found in the Deregistration Result parameter, indicating success or 3825 failure with cause. 3827 An ASP MAY deregister multiple Routing Contexts at once by including a 3828 number of Routing Contexts in a single DEREG REQ message. The SGP MAY 3829 respond to each deregistration request in a single DEREG RSP message, 3830 indicating the success or failure result for each Routing Context in a 3831 separate Deregistration Result parameter. 3833 4.3 Procedures to Support the Availability or Congestion Status of SS7 3834 Destination 3836 4.3.1 At an SGP 3838 On receiving an MTP-PAUSE, MTP-RESUME or MTP-STATUS indication 3839 primitive from the nodal inter-working function at an SGP, the SGP M3UA 3840 layer will send a corresponding SS7 Signalling Network Management 3841 (SSNM) DUNA, DAVA, SCON, or DUPU message (see Section 3.4) to the M3UA 3842 peers at concerned ASPs. The M3UA layer must fill in various fields of 3843 the SSNM messages consistently with the information received in the 3844 primitives. 3846 The SGP M3UA layer determines the set of concerned ASPs to be informed 3847 based on the SS7 network partition for which the primitive indication 3848 is relevant. In this way, all ASPs configured to send/receive traffic 3849 within a particular network appearance are informed. If the SGP 3850 operates within a single SS7 network appearance, then all ASPs are 3851 informed. 3853 The SG M3UA MAY filter further based on the Affected Point Code in the 3854 MTP-PAUSE, MTP-RESUME or MTP-STATUS indication primitives. In this way 3855 ASPs can be informed only of affected destinations to which they 3856 actually communicate. The SGP M3UA layer MAY also suppress DUPU 3857 messages to ASPs that do not implement an MTP3-User protocol peer for 3858 the affected MTP3-User. 3860 DUNA, DAVA, SCON, and DRST messages MUST be sent sequentially and processed at 3861 the receiver in the order sent. SCTP stream "0" is used to provide the 3862 sequencing. . The only exception to this is if the international congestion 3863 method (see Q.704) is used. If so, the Unordered bit in the SCTP DATA chunk MAY 3864 be used for the SCON message. 3866 Sequencing is not required for the DUPU or DAUD messages, which MAY 3867 be sent un-sequenced. Again, SCTP stream 0 is used, with optional use 3868 of the Unordered bit in the SCTP DATA chunk. 3870 4.3.2 At an ASP 3872 4.3.2.1 Single SGP Configurations 3874 At an ASP, upon receiving an SS7 Signalling Network Management (SSNM) 3875 message from the remote M3UA Peer, the M3UA layer invokes the 3876 appropriate primitive indications to the resident M3UA-Users. Local 3877 management is informed. 3879 In the case where a local event has caused the unavailability or 3880 congestion status of SS7 destinations, the M3UA layer at the ASP MUST 3881 pass up appropriate indications in the primitives to the M3UA User, as 3882 though equivalent SSNM messages were received. For example, the loss 3883 of an SCTP association to an SGP may cause the unavailability of a set 3884 of SS7 destinations. MTP-PAUSE indication primitives to the M3UA User 3885 are appropriate. To accomplish this, the M3UA layer at an ASP 3886 maintains the status of routes via the SG(P), much like an MTP3 layer 3887 maintains route-set status. 3889 4.3.2.2 Multiple SGP Configurations 3891 At an ASP, upon receiving a Signalling Network Management message from 3892 the remote M3UA Peer, the M3UA layer updates the status of the affected 3893 route(s) via the originating SGP and determines, whether or not the 3894 overall availability or congestion status of the effected 3895 destination(s) has changed. If so, the M3UA layer invokes the 3896 appropriate primitive indications to the resident M3UA-Users. Local 3897 management is informed. 3899 An M3UA layer at the ASP MAY choose to maintain knowledge of which SGPs 3900 are included in Signalling Gateways for the purpose of interpreting 3901 SSNM messaging from one SGP so as to apply to all the SGPs in the SG. 3903 4.3.3 ASP Auditing 3905 An ASP may optionally initiate an audit procedure in order to enquire 3906 of an SGP the availability and, if the national congestion method with 3907 multiple congestion levels and message priorities is used, congestion 3908 status of an SS7 destination or set of destinations. A Destination 3909 Audit (DAUD) message is sent from the ASP to the SGP requesting the 3910 current availability and congestion status of one or more SS7 3911 Destination Point Codes. 3913 The DAUD message MAY be sent un-sequenced. The DAUD MAY be sent by the 3914 ASP in the following cases: 3916 - Periodic. A Timer originally set upon reception of a DUNA, SCON 3917 or DRST message has expired without a subsequent DAVA, 3918 DUNA, SCON or DRST message updating the 3919 availability/congestion status of the affected 3920 Destination Point Codes. The Timer is reset upon 3921 issuing a DAUD. In this case the DAUD is sent to the 3922 SGP that originally sent the SSNM message. 3924 - Isolation. The ASP is newly ASP-INACTIVE or ASP-ACTIVE or has been 3925 isolated from an SGP for an extended period. The ASP 3926 MAY request the availability/congestion status of one 3927 or more SS7 destinations to which it expects to 3928 communicate. 3930 In the first of the cases above, the auditing procedure must not be 3931 invoked for the case of a received SCON message containing a congestion 3932 level value of "no congestion" or undefined" (i.e., congestion Level = 3933 "0"). This is because the value indicates either congestion abatement 3934 or that the ITU MTP3 international congestion method is being used. In 3935 the international congestion method, the MTP3 layer at the SGP does not 3936 maintain the congestion status of any destinations and therefore the 3937 SGP cannot provide any congestion information in response to the DAUD. 3938 For the same reason, in the second of the cases above a DAUD message 3939 cannot reveal any congested destination(s). 3941 The SGP MUST respond to a DAUD message with the MTP3 3942 availability/congested status of the routeset associated with each 3943 Destination Point Code(s) in the DAUD message. The status of each SS7 3944 destination requested is indicated in a DUNA message (if unavailable), 3945 a DAVA message (if available), or a DRST (if restricted and the SGP 3946 supports this feature). If the SS7 destination is available and 3947 congested, the SGP responds with an SCON message in addition to the 3948 DAVA message. If the SS7 destination is restricted and congested, the 3949 SGP responds with an SCON message in addition to the DRST. If the SGP 3950 has no information on the availability/congestion status of the SS7 3951 destination, the SGP responds with a DUNA message, as it has no routing 3952 information to allow it to route traffic to this destination 3954 Any DUNA or DAVA message in response to a DAUD message MAY contain a 3955 list of up to sixteen Affected Point Codes. 3957 4.4 MTP3 Restart 3959 In the case where the MTP3 in the SG undergoes an MTP restart, event 3960 communication SHOULD be handled as follows: 3962 When the SG discovers SS7 network isolation, the SGPs send an indication 3963 to all concerned available ASPs (i.e., ASPs in the ASP-ACTIVE, ASP- 3964 STANDBY or ASP-INACTIVE state) using a DUNA message. For the purpose of 3965 MTP restart, all Signalling Point Management Clusters with point codes 3966 different from that of the SG with at least one ASP in the ASP-ACTIVE 3967 state or that has sent an ASP ACTIVE message to the SG during the first 3968 part of the restart procedure should be considered as available. If the 3969 M3UA layer at the SGP receives any ASP ACTIVE messages during the 3970 restart procedure, it delays the ASP ACTIVE ACK messages until the end 3971 of the restart procedure. During the second part of the restart 3972 procedure the SGP M3UA layers at the SGPs inform all concerned ASPs in 3973 the ASP-ACTIVE, ASP-STANDBY or ASP-INACTIVE states of any unavailable 3974 SS7 destinations using the DUNA message. At the end of the restart 3975 procedure the SGP M3UA layers send an ASP ACTIVE ACK message to all ASPs 3976 in the ASP-ACTIVE state. 3978 When the M3UA layer at an ASP receives a DUNA message indicating SS7 3979 network isolation at an SG, it will stop any affected traffic via this 3980 route. When the M3UA subsequently receives any DUNA messages from an SGP 3981 it will mark the affected SS7 destinations as unavailable via that SG. 3982 When the M3UA receives an ASP ACTIVE ACK message it can resume traffic 3983 to available SS7 destinations via this SGP, provided the ASP is in the 3984 ASP-ACTIVE state towards this SGP. The ASP MAY choose to audit the 3985 availability of any unavailable destinations 3987 5. Examples of M3UA Procedures 3989 5.1 Establishment of Association and Traffic between SGPs and ASPs 3991 5.1.1 Single ASP in an Application Server ("1+0" sparing), 3993 5.1.1.1 Single ASP in an Application Server ("1+0" sparing), No 3994 Registration 3996 This scenario shows the example M3UA message flows for the 3997 establishment of traffic between an SGP and an ASP, where only one ASP 3998 is configured within an AS (no backup). It is assumed that the SCTP 3999 association is already set-up. The sending of any DUNA/SCON messages by 4000 the SGP is not shown but is similar to the case described in Section 4001 5.1.2. 4003 SGP ASP1 4004 | | 4005 |<-------------ASP Up------------| 4006 |-----------ASP Up Ack---------->| 4007 | | 4008 |<------- ASP Active(RCn)--------| RC: Routing Context 4009 |-----ASP Active Ack (RCn)------>| (optional) 4010 | | 4012 Note: If the ASP Active message contains an optional Routing Context 4013 parameter, The ASP Active message only applies for the specified RC 4014 value(s). For an unknown RC value, the SGP responds with an Error 4015 message. 4017 5.1.1.2 Single ASP in Application Server ("1+0" sparing), Dynamic 4018 Registration 4020 This scenario is the same as for 5.1.1.1 but with the optional exchange 4021 of registration information. In this case the Registration is accepted 4022 by the SGP. 4024 SGP ASP1 4025 | | 4026 |<------------ASP Up-------------| 4027 |----------ASP Up Ack----------->| 4028 | | 4029 |<----REGISTER REQ(LRCn,RKn)-----| LRC: Local Routing 4030 | | Context 4031 |----REGISTER RESP(LRCn,RCn)---->| RK: Routing Key 4032 | | RC: Routing Context 4033 | | 4034 |<------- ASP Active(RCn)--------| 4035 |-----ASP Active Ack (RCn)------>| 4036 | | 4038 Note: In the case of an unsuccessful registration attempt (e.g., 4039 Invalid RKn), the Register Response message will contain an 4040 unsuccessful indication and the ASP will not subsequently send an ASP 4041 Active message. 4043 5.1.1.3 Single ASP in Multiple Application Servers (each with "1+0" 4044 sparing), Dynamic Registration (Case 1 � Multiple Registration 4045 Requests) 4047 SGP ASP1 4048 | | 4049 |<------------ASP Up-------------| 4050 |----------ASP Up Ack----------->| 4051 | | 4052 |<----REGISTER REQ(LRC1,RK1)-----| LRC: Local Routing 4053 | | Context 4054 |----REGISTER RESP(LRC1,RC1)---->| RK: Routing Key 4055 | | RC: Routing Context 4056 | | 4057 |<------- ASP Active(RC1)--------| 4058 |-----ASP Active Ack (RC1)------>| 4059 | | 4060 | | 4061 |<----REGISTER REQ(LRCn,RKn)-----| 4062 | | 4063 |----REGISTER RESP(LRCn,RCn)---->| 4064 | | 4065 | | 4066 |<------- ASP Active(RCn)--------| 4067 |-----ASP Active Ack (RCn)------>| 4068 | | 4070 Note: In the case of an unsuccessful registration attempt (e.g., 4071 Invalid RKn), the Register Response message will contain an 4072 unsuccessful indication and the ASP will not subsequently send an ASP 4073 Active message. Each LRC/RK pair registration is considered 4074 independently. 4076 It is not necessary to follow a Registration Request/Response message 4077 pair with an ASP Active message before sending the next Registration 4078 Request. The ASP Active message can be sent at any time after the 4079 related successful registration. 4081 5.1.1.4 Single ASP in Multiple Application Servers (each with "1+0" 4082 sparing), Dynamic Registration (Case 2 � Single Registration Request) 4084 SGP ASP1 4085 | | 4086 |<------------ASP Up-------------| 4087 |----------ASP Up Ack----------->| 4088 | | 4089 |<---REGISTER REQ({LRC1,RK1},----| 4090 | ..., | 4091 | {LRCn,RKn}),----| 4092 | | 4093 |---REGISTER RESP({LRC1,RC1},--->| 4094 | ..., | 4095 | (LRCn,RCn}) | 4096 | | 4097 |<------- ASP Active(RC1)--------| 4098 |-----ASP Active Ack (RC1)------>| 4099 | | 4100 : : 4101 : : 4102 | | 4103 |<------- ASP Active(RCn)--------| 4104 |-----ASP Active Ack (RCn)------>| 4105 | | 4107 Note: In the case of an unsuccessful registration attempt (e.g., 4108 Invalid RKn), the Register Response message will contain an 4109 unsuccessful indication and the ASP will not subsequently send an ASP 4110 Active message. Each LRC/RK pair registration is considered 4111 independently. 4113 The ASP Active message can be sent at any time after the related 4114 successful registration, and may have more than one RC. 4116 5.1.2 Two ASPs in Application Server ("1+1" sparing) 4118 This scenario shows the example M3UA message flows for the 4119 establishment of traffic between an SGP and two ASPs in the same 4120 Application Server, where ASP1 is configured to be in the ASP-ACTIVE 4121 state and ASP2 is to be a "back-up" in the event of communication 4122 failure or the withdrawal from service of ASP1. ASP2 may act as a hot, 4123 warm, or cold back-up depending on the extent to which ASP1 and ASP2 4124 share call/transaction state or can communicate call state under 4125 failure/withdrawal events. The example message flow is the same 4126 whether the ASP Active messages indicate "Over-ride" or "Load-share" 4127 mode, although typically this example would use an Over-ride mode. The 4128 SGP MAY start sending any relevant DUNA, DRST and SCON messages to ASPs 4129 as soon as they enter the ASP-INACTIVE state. In the case of MTP 4130 Restart, the ASP-Active Ack message is only sent after all relevant 4131 DUNA/DRST/SCON messages have been transmitted to the concerned ASP. 4133 SGP ASP1 ASP2 4134 | | | 4135 |<--------ASP Up----------| | 4136 |-------ASP Up Ack------->| | 4137 | | | 4138 |<-----------------------------ASP Up----------------| 4139 |-----------------------------ASP Up Ack------------>| 4140 | | | 4141 | | | 4142 |<-------ASP Active-------| | 4143 |------ASP Active Ack---->| | 4144 | | | 4146 Note: It is also possible for ASP2 to send an ASP-Active ("Over-ride- 4147 Standby") message after ASP1 goes ASP-ACTIVE A similar sparing 4148 arrangement is created, except that the SGP may re-direct traffic to 4149 ASP2 more quickly in certain fail-over cases. 4151 5.1.3 Two ASPs in an Application Server ("1+1" sparing, load-sharing 4152 case) 4154 This scenario shows a similar case to Section 5.1.2 but where the two 4155 ASPs are brought to the state ASP-ACTIVE and subsequently load-share 4156 the traffic. In this case, one ASP is sufficient to handle the total 4157 traffic load. The sending of DUNA, DRST and SCON messages by the SGP is 4158 not shown but is similar to the case described in Section 5.1.2. 4160 SGP ASP1 ASP2 4161 | | | 4162 |<---------ASP Up---------| | 4163 |--------ASP Up Ack------>| | 4164 | | | 4165 |<------------------------------ASP Up---------------| 4166 |-----------------------------ASP Up Ack------------>| 4167 | | | 4168 | | | 4169 |<--ASP Active (Ldshr)----| | 4170 |-----ASP-Active Ack----->| | 4171 | | | 4172 |<----------------------------ASP Active (Ldshr)-----| 4173 |-------------------------------ASP Active Ack------>| 4174 | | | 4176 5.1.4 Three ASPs in an Application Server ("n+k" sparing, load-sharing 4177 case) 4179 This scenario shows the example M3UA message flows for the 4180 establishment of traffic between an SGP and three ASPs in the same 4181 Application Server, where two of the ASPs are brought to the state ASP- 4182 ACTIVE and subsequently share the load. In this case, a minimum of two 4183 ASPs are required to handle the total traffic load (2+1 sparing). The 4184 sending of DUNA, DRST and SCON messages by the SGP is not shown but is 4185 similar to the case described in Section 5.1.2. 4187 SGP ASP1 ASP2 ASP3 4188 | | | | 4189 |<------ASP Up-------| | | 4190 |-----ASP Up Ack---->| | | 4191 | | | | 4192 |<--------------------------ASP Up-------| | 4193 |-------------------------ASP Up Ack---->| | 4194 | | | | 4195 |<---------------------------------------------ASP Up--------| 4196 |---------------------------------------------ASP Up Ack---->| 4197 | | | | 4198 | | | | 4199 |<--ASP Act (Ldshr)--| | | 4200 |----ASP Act Ack---->| | | 4201 | | | | 4202 |<--------------------ASP Act. (Ldshr)---| | 4203 |-----------------------ASP Act Ack----->| | 4204 | | | | 4206 Note: It is also possible for ASP3 to send an ASP Active message 4207 ("Loadshare-Standby") after ASP1 and ASP2 go to the ASP-ACTIVE state A 4208 similar sparing arrangement is created, except that the SGP may 4209 redirect traffic to ASP3 more quickly in certain fail-over cases. 4211 5.2 ASP Traffic Fail-over Examples 4213 5.2.1 (1+1 Sparing, Withdrawal of ASP, Back-up Over-ride) 4215 Following on from the example in Section 5.1.2, and ASP1 withdraws from 4216 service: 4218 SGP ASP1 ASP2 4219 | | | 4220 |<-----ASP Inactive-------| | 4221 |----ASP Inactive Ack---->| | 4222 |------------------------NTFY(AS-Pending)----------->| 4223 | | | 4224 |<------------------------------ ASP Active----------| 4225 |------------------------------ASP Active Ack------->| 4226 | | 4228 Note: If the SGP M3UA layer detects the loss of the M3UA peer (M3UA 4229 heartbeat loss or detection of SCTP failure), the initial ASP Inactive 4230 message exchange (i.e., SGP to ASP1) would not occur. 4232 5.2.2 (1+1 Sparing, Back-up Over-ride) 4234 Following on from the example in Section 5.1.2, and ASP2 wishes to 4235 over-ride ASP1 and take over the traffic: 4237 SGP ASP1 ASP2 4238 | | | 4239 |<------------------------------ ASP Active----------| 4240 |-------------------------------ASP Active Ack------>| 4241 |----NTFY(Alt ASP-Act)--->| 4242 | | | 4244 5.2.3 (n+k Sparing, Load-sharing case, Withdrawal of ASP) 4246 Following on from the example in Section 5.1.4, and ASP1 withdraws from 4247 service: 4249 SGP ASP1 ASP2 ASP3 4250 | | | | 4251 |<----ASP Inact.-----| | | 4252 |---ASP Inact Ack--->| | | 4253 | | | | 4254 |---------------------------------NTFY(Ins. ASPs)----------->| 4255 | | | | 4256 |<-----------------------------------------ASP Act (Ldshr)---| 4257 |-------------------------------------------ASP Act (Ack)--->| 4258 | | | | 4260 For the Notify message to be sent, the SG maintains knowledge of the 4261 minimum ASP resources required (e.g., if the SG knows that "n+k" = 4262 "2+1" for a load-share AS and "n" currently equals "1"). 4264 Note: If the SGP detects loss of the ASP1 M3UA peer (M3UA heartbeat 4265 loss or detection of SCTP failure), the initial ASP Inactive message 4266 exchange (i.e., SGP-ASP1) would not occur. 4268 5.3 Normal Withdrawal of an ASP from an Application Server and Tear- 4269 down of an Association 4271 An ASP which is now confirmed in the state ASP-INACTIVE (i.e., the ASP 4272 has received an ASP Inactive Ack message) may now proceed to the ASP- 4273 DOWN state, if it is to be removed from service. Following on from 4274 Section 5.2.1 or 5.2.3, where ASP1 has moved to the "Inactive" state: 4276 SGP ASP1 4277 | | 4278 |<-----ASP Inactive (RCn)-------| RC: Routing Context 4279 |----ASP Inactive Ack (RCn)---->| 4280 | | 4281 |<-----DEREGISTER REQ(RCn)------| See Notes 4282 | | 4283 |---DEREGISTER RESP(LRCn,RCn)-->| 4284 | | 4285 : : 4286 | | 4287 |<-----------ASP Down-----------| 4288 |---------ASP Down Ack--------->| 4289 | | 4291 Note: The Deregistration procedure MUST be used if the ASP previously 4292 used the Registration procedures for configuration within the 4293 Application Server. ASP Inactive and Deregister messages exchanges may 4294 contain multiple Routing Contexts. 4296 The ASP SHOULD be ASP-INACTIVE and de-registered in all its Routing 4297 Contexts before attempting to move to the ASP-DOWN state. 4299 5.4 M3UA/MTP3-User Boundary Examples 4301 5.4.1 At an ASP 4303 This section describes the primitive mapping between the MTP3 User and 4304 the M3UA layer at an ASP. 4306 5.4.1.1 Support for MTP-TRANSFER Primitives at the ASP 4308 5.4.1.1.1 Support for MTP-TRANSFER Request Primitive 4310 When the MTP3-User on the ASP has data to send into the SS7 network, it 4311 uses the MTP-TRANSFER request primitive. The M3UA layer at the ASP 4312 will do the following when it receives an MTP-TRANSFER request 4313 primitive from the M3UA user: 4315 - Determine the correct SGP; 4317 - Determine the correct association to the chosen SGP; 4319 - Determine the correct stream in the association (e.g., based on 4320 SLS); 4322 - Determine whether to complete the optional fields of the DATA 4323 message; 4325 - Map the MTP-TRANSFER request primitive into the Protocol Data 4326 field of a DATA message; 4328 - Send the DATA message to the remote M3UA peer at the SGP, over the 4329 SCTP association. 4331 SGP ASP 4332 | | 4333 |<-----DATA Message-------|<--MTP-TRANSFER req. 4334 | | 4336 5.4.1.1.2 Support for the MTP�TRANSFER Indication Primitive 4338 When the M3UA layer on the ASP receives a DATA message from the remote 4339 M3UA peer at the SGP, it will do the following: 4341 - Evaluate the optional fields of the DATA message, if present; 4342 - Map the Protocol Data field of a DATA message into the MTP-TRANSFER 4343 indication primitive; 4345 - Pass the MTP-TRANSFER indication primitive to the user part. In 4346 case of multiple user parts, the optional fields of the Data 4347 message are used to determine the concerned user part. 4349 SGP ASP 4350 | | 4351 |------Data Message------>|-->MTP-Transfer ind. 4352 | | 4354 5.4.1.1.3 Support for ASP Querying of SS7 Destination States 4356 There are situations such as temporary loss of connectivity to the SGP 4357 that may cause the M3UA layer at the ASP to audit SS7 destination 4358 availability/congestion states. Note: there is no primitive for the 4359 MTP3-User to request this audit from the M3UA layer as this is 4360 initiated by an internal M3UA management function. 4362 SGP ASP 4363 | | 4364 |<----------DAUD----------| 4365 |<----------DAUD----------| 4366 |<----------DAUD----------| 4367 | | 4368 | | 4370 5.4.2 At an SGP 4372 This section describes the primitive mapping between the MTP3-User and 4373 the M3UA layer at an SGP. 4375 5.4.2.1 Support for MTP-TRANSFER Request Primitive at the SGP 4377 When the M3UA layer at the SGP has received DATA messages from its peer 4378 destined to the SS7 network it will do the following: 4380 - Evaluate the optional fields of the DATA message, if present, to 4381 determine the Network Appearance; 4383 - Map the Protocol data field of the DATA message into an MTP- 4384 TRANSFER request primitive; 4386 - Pass the MTP-TRANSFER request primitive to the MTP3 of the 4387 concerned Network Appearance. 4389 SGP ASP 4390 | | 4391 <---MTP-TRANSFER req.|<---------DATA ----------| 4392 | | 4394 5.4.2.2 Support for MTP-TRANSFER Indication Primitive at the SGP 4396 When the MTP3 layer at the SGP has data to pass its user parts, it will 4397 use the MTP-TRANSFER indication primitive. The M3UA layer at the SGP 4398 will do the following when it receives an MTP-TRANSFER indication 4399 primitive: 4401 - Determine the correct ASP; 4403 - Determine the correct association to the chosen ASP; 4405 - Determine the correct stream in the association (e.g., based on 4406 SLS); 4408 - Determine whether to complete the optional fields of the DATA 4409 message; 4411 - Map the MTP-TRANSFER indication primitive into the Protocol Data 4412 field of a DATA message; 4414 - Send the DATA message to the remote M3UA peer in the ASP, over the 4415 SCTP association 4417 SGP ASP 4418 | | 4419 --MTP-TRANSFER ind.->|----------DATA --------->| 4420 | | 4422 5.4.2.3 Support for MTP-PAUSE, MTP-RESUME, MTP-STATUS Indication 4423 Primitives 4425 The MTP-PAUSE, MTP-RESUME and MTP-STATUS indication primitives from the 4426 MTP3 upper layer interface at the SGP need to be made available to the 4427 remote MTP3 User Part lower layer interface at the concerned ASP(s). 4429 5.4.2.3.1 Destination Unavailable 4431 The MTP3 layer at the SGP will generate an MTP-PAUSE indication 4432 primitive when it determines locally that an SS7 destination is 4433 unreachable. The M3UA layer will map this primitive to a DUNA message. 4434 The SGP M3UA layer determines the set of concerned ASPs to be informed 4435 based on internal SS7 network information associated with the MTP-PAUSE 4436 indication primitive indication. 4438 SGP ASP 4439 | | 4440 --MTP-PAUSE ind.-->|---------DUNA----------->|--MTP-PAUSE ind.--> 4441 | | 4443 5.4.2.3.2 Destination Available 4445 The MTP3 at the SGP will generate an MTP-RESUME indication primitive 4446 when it determines locally that an SS7 destination that was previously 4447 unreachable is now reachable. The M3UA layer will map this primitive 4448 to a DAVA message. The SGP M3UA determines the set of concerned ASPs 4449 to be informed based on internal SS7 network information associated 4450 with the MTP-RESUME indication primitive. 4452 SGP ASP 4453 | | 4454 --MTP-RESUME ind.-->|-----------DAVA--------->|--MTP-RESUME ind.--> 4455 | | 4457 5.4.2.3.3 SS7 Network Congestion 4459 The MTP3 layer at the SGP will generate an MTP-STATUS indication 4460 primitive when it determines locally that the route to an SS7 4461 destination is congested. The M3UA layer will map this primitive to a 4462 SCON message. It will determine which ASP(s) to send the SCON message 4463 to, based on the intended Application Server. 4465 SGP ASP 4466 | | 4467 --MTP-STATUS ind.-->|-----------SCON--------->|--MTP-STATUS ind.--> 4468 | | 4470 5.4.2.3.4 Destination User Part Unavailable 4472 The MTP3 layer at the SGP will generate an MTP-STATUS indication 4473 primitive when it receives an UPU message from the SS7 network. The 4474 M3UA layer will map this primitive to a DUPU message. It will 4475 determine which ASP(s) to send the DUPU based on the intended 4476 Application Server. 4478 SGP ASP 4479 | | 4480 --MTP-STATUS ind.-->|----------DUPU---------->|--MTP-STATUS ind.--> 4481 | | 4483 6. Security 4485 6.1 Introduction 4487 M3UA is designed to carry signalling messages for telephony services. 4488 As such, M3UA must involve the security needs of several parties: the 4489 end users of the services; the network providers and the applications 4490 involved. Additional requirements may come from local regulation. 4491 While having some overlapping security needs, any security solution 4492 should fulfil all of the different parties' needs. 4494 6.2 Threats 4496 There is no quick fix, one-size-fits-all solution for security. As a 4497 transport protocol, M3UA has the following security objectives: 4499 * Availability of reliable and timely user data transport. 4500 * Integrity of user data transport. 4501 * Confidentiality of user data. 4503 M3UA is recommended to be transported on SCTP. SCTP [13] provides 4504 certain transport related security features, such as some protection 4505 against: 4507 * Blind Denial of Service Attacks 4508 * Flooding 4509 * Masquerade 4510 * Improper Monopolization of Services 4512 When M3UA is running in professionally managed corporate or service 4513 provider network, it is reasonable to expect that this network includes 4514 an appropriate security policy framework. The "Site Security Handbook" 4515 [21] should be consulted for guidance. 4517 When the network in which M3UA runs in involves more than one party, it 4518 may not be reasonable to expect that all parties have implemented 4519 security in a sufficient manner. In such a case, it is recommended 4520 that IPSEC is used to ensure confidentiality of user payload. Consult 4521 [22] for more information on configuring IPSEC services. 4523 6.3 Protecting Confidentiality 4525 Particularly for mobile users, the requirement for confidentiality may 4526 include the masking of IP addresses and ports. In this case 4527 application level encryption is not sufficient; IPSEC ESP [23] SHOULD 4528 be used instead. Regardless of which level performs the encryption, 4529 the IPSEC ISAKMP [24] service SHOULD be used for key management. 4531 7. IANA Considerations 4533 7.1 SCTP Payload Protocol Identifier 4535 IANA has assigned an M3UA value for the Payload Protocol Identifier in 4536 the SCTP DATA chunk. The following SCTP Payload Protocol Identifier is 4537 registered: 4539 M3UA "3" 4541 The SCTP Payload Protocol Identifier value "3" SHOULD be included in 4542 each SCTP DATA chunk, to indicate that the SCTP is carrying the M3UA 4543 protocol. The value "0" (unspecified) is also allowed but any other 4544 values MUST not be used. This Payload Protocol Identifier is not 4545 directly used by SCTP but MAY be used by certain network entities to 4546 identify the type of information being carried in a DATA chunk. 4548 The User Adaptation peer MAY use the Payload Protocol Identifier as a 4549 way of determining additional information about the data being 4550 presented to it by SCTP. 4552 7.2 M3UA Port Number 4554 IANA has registered SCTP (and UDP/TCP) Port Number 2905 for M3UA. 4556 7.3 M3UA Protocol Extensions 4558 This protocol may also be extended through IANA in three ways: 4559 -- through definition of additional message classes, 4560 -- through definition of additional message types, and 4561 -- through definition of additional message parameters 4563 The definition and use of new message classes, types and parameters is 4564 an integral part of SIGTRAN adaptation layers. Thus these extensions 4565 are assigned by IANA through an IETF Consensus action as defined in 4566 Guidelines for Writing an IANA Considerations Section in RFCs (25] 4568 The proposed extension must in no way adversely affect the general 4569 working of the protocol. 4571 7.3.1 IETF Defined Message Classes 4573 The documentation for a new message class MUST include the following 4574 information: 4575 (a) A long and short name for the new message class; 4576 (b) A detailed description of the purpose of the message class. 4578 7.3.2 IETF Defined Message Types 4580 The documentation for a new message type MUST include the following 4581 information: 4583 (a) A long and short name for the new message type; 4584 (b) A detailed description of the structure of the message;. 4585 (c) A detailed definition and description of intended use for each 4586 field within the message; 4587 (d) A detailed procedural description of the use of the new message 4588 type within the operation of the protocol; 4589 (e) A detailed description of error conditions when receiving this 4590 message type. 4592 When an implementation receives a message type which it does not 4593 support, it MUST respond with an Error (ERR) message ("Unsupported 4594 Message Type"). 4596 7.3.3 IETF Defined Parameter Extension 4598 Documentation of the message parameter MUST contain the following 4599 information: 4601 (a) Name of the parameter type; 4602 (b) Detailed description of the structure of the parameter field. This 4603 structure MUST conform to the general type-length-value format 4604 described in Section 3.2; 4605 (c) Detailed definition of each component of the parameter value; 4606 (d) Detailed description of the intended use of this parameter type, 4607 and an indication of whether and under what circumstances multiple 4608 instances of this parameter type may be found within the same 4609 message. 4611 8. Acknowledgements 4613 The authors would like to thank Antonio Roque Alvarez, Joyce Archibald, 4614 Tolga Asveren, Brian Bidulock, Dan Brendes, Nikhil Jain, Joe Keller, 4615 Kurt Kite, Ming Lin, Steve Lorusso, John Loughney, Naoto Makinae, 4616 Howard May, Barry Nagelberg, Neil Olson, Heinz Prantner, Shyamal 4617 Prasad, Mukesh Punhani, Selvam Rengasami, Ray Singh, Michael Tuexen, 4618 Nitin Tomar, Gery Verwimp, Kazuo Watanabe, Ben Wilson and many others 4619 for their valuable comments and suggestions. 4621 9. References 4623 [1] RFC 2719, "Framework Architecture for Signaling Transport", L. Ong 4624 et al, October 1999 4626 [2] ITU-T Recommendations Q.761 to Q.767, "Signalling System No.7 (SS7) 4627 - ISDN User Part (ISUP)" 4629 [3] ANSI T1.113 � "Signaling System Number 7 - ISDN User Part" 4630 [4] ETSI ETS 300 356-1 "Integrated Services Digital Network (ISDN); 4631 Signalling System No.7; ISDN User Part (ISUP) version 2 for the 4632 international interface; Part 1: Basic services" 4634 [5] ITU-T Recommendations Q.711 to Q.715, "Signalling System No. 7 4635 (SS7) - Signalling Connection Control Part (SCCP)" 4637 [6] ANSI T1.112 "Signaling System Number 7 - Signaling Connection 4638 Control Part" 4640 [7] ETSI ETS 300 009-1, "Integrated Services Digital Network (ISDN); 4641 Signalling System No.7; Signalling Connection Control Part (SCCP) 4642 (connectionless and connection-oriented class 2) to support 4643 international interconnection; Part 1: Protocol specification" 4645 [8] ITU-T Recommendation Q.720, "Telephone User Part" 4647 [9] ITU-T Recommendations Q.771 to Q.775 "Signalling System No. 7 (SS7) - 4648 Transaction Capabilities (TCAP)" 4650 [10] ANSI T1.114 "Signaling System Number 7 - Transaction Capabilities 4651 Application Part" 4653 [11] ETSI ETS 300 287-1, "Integrated Services Digital Network (ISDN); 4654 Signalling System No.7; Transaction Capabilities (TC) version 2; 4655 Part 1: Protocol specification" 4657 [12] 3G TS 25.410 V4.0.0 (2001-04) "Technical Specification - 3rd 4658 Generation partnership Project; Technical Specification Group 4659 Radio Access Network; UTRAN Iu Interface: General Aspects and 4660 Principles" 4662 [13] RFC 2960, "Stream Control Transport Protocol", R. Stewart et al, 4663 October 2000. 4665 [14] ITU-T Recommendations Q.701 to Q.705, "Signalling System No. 7 4666 (SS7) - Message Transfer Part (MTP)" 4668 [15] ANSI T1.111 "Signaling System Number 7 - Message Transfer Part" 4670 [16] ETSI ETS 300 008-1, "Integrated Services Digital Network (ISDN); 4671 Signalling System No.7; Message Transfer Part (MTP) to support 4672 international interconnection; Part 1: Protocol specification" 4674 [17] ITU-T Recommendation Q.2140 "B-ISDN ATM Adaptation Layer - Service 4675 Specific Coordination Function for signalling at the Network Node 4676 Interface (SSCF at NNI)" 4678 [18] ITU-T Recommendation Q.2110 "B-ISDN ATM Adaptation Layer - Service 4679 Specific Connection Oriented Protocol (SSCOP)" 4681 [19] RFC 2119, "Key words for use in RFCs to Indicate Requirement 4682 Levels", S. Bradner, March 1997. 4684 [20] ITU-T Recommendation Q.2210 "Message Transfer Part Level 3 4685 functions and messages using the services of ITU Recommendation 4686 Q.2140" 4688 [21] RFC 2196, "Site Security Handbook", B. Fraser Ed., September 1997 4690 [22] RFC 2401, "Security Architecture for the Internet Protocol", S. 4691 Kent, R. Atkinson, November 1998. 4693 [23] RFC 2406, "IP Encapsulating Security Payload (ESP)", S.Kent and 4694 R. Atkinson, November 1998. 4696 [24] RFC 2408, "Internet Security Association and Key Management 4697 Protocol", D. Maughan, M. Schertler, M. Schneider and J. Turner, 4698 November 1998. 4700 [25] RFC 2434, "Guidelines for Writing an IANA Considerations Section 4701 in RFCs", T. Narten and H. Alvestrand, October 1998 4703 10. Bibliography 4705 [26] , "MTP2-User Adaptation Layer", 4706 K. Morneault et al, February 2001 (Work in Progress) 4708 11. Author's Addresses 4710 Greg Sidebottom 4711 Kanata, Ontario, Canada 4712 gregside@home.com 4714 Guy Mousseau 4715 Nortel Networks 4716 3685 Richmond Rd 4717 Nepean, Ontario, Canada K2H 5B7 4719 Lyndon Ong 4720 Ciena 4721 10480 Ridgeview Court 4722 Cupertino, CA 95014 4723 lyong@ciena.com 4725 Ian Rytina 4726 Ericsson Australia 4727 37/360 Elizabeth Street 4728 Melbourne, Victoria 3000, Australia 4729 ian.rytina@ericsson.com.au 4730 Hanns Juergen Schwarzbauer 4731 SIEMENS AG 4732 Hofmannstr. 51 4733 81359 Munich, Germany 4734 HannsJuergen.Schwarzbauer@icn.siemens.de 4736 Klaus D. Gradischnig 4737 NeuStar, Inc 4738 1120 Vermont Ave. N.W.Suite 400 4739 Washington D.C 20005 4740 klaus.gradischnig@neustar.com 4742 Ken Morneault 4743 Cisco Systems Inc. 4744 13615 Dulles Technology Drive 4745 Herndon, VA, USA 20171 4746 EMail: kmorneau@cisco.com 4748 Malleswar Kalla 4749 Telcordia Technologies 4750 MCC 1J211R 4751 445 South Street 4752 Morristown, NJ, USA 07960 4753 Email: kalla@research.telcordia.com 4755 Normand Glaude 4756 Performance Technologies 4757 150 Metcalf Sreet, Suite 1300 4758 Ottawa, Ontario, Canada K2P 1P1 4759 EMail: nglaude@microlegend.com 4761 This draft expires December 2001.