1、 ETSI EG 202 360 V1.1.1 (2004-12)ETSI Guide Telecommunications and Internet converged Services andProtocols for Advanced Networking (TISPAN);Architectural scenarios and applicability for different SIGTRAN adaptation layers;SIGTRAN scenariosETSI ETSI EG 202 360 V1.1.1 (2004-12) 2 Reference DEG/TISPAN
2、-03013-Tech Keywords architecture, protocol, SIGTRAN, M2UA, M3UA, SUA ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 78
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6、ation No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2004. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered fo
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8、nts Intellectual Property Rights4 Foreword.4 Introduction 4 1 Scope 5 2 References 5 3 Definitions and abbreviations.6 3.1 Definitions6 3.2 Abbreviations .6 4 Network architectures using SS7 over IP.7 4.1 General architectural considerations 7 4.2 General protocol aspects 9 4.2.1 SS7 protocol stack
9、in TDM/ATM networks .9 4.2.2 SS7 protocol stack in TDM/ATM and IP networks10 4.2.2.1 MTP2-User Peer-to-Peer Adaptation Layer (M2PA)10 4.2.2.2 Message Transfer Part 2 User Adaptation Layer (M2UA)11 4.2.2.3 Message Transfer Part 3 User Adaptation Layer (M3UA)12 4.2.2.3.1 SS7 network impacts with IETF
10、based M3UA during failure situations.13 4.2.2.3.2 SS7 network impacts with ETSI based M3UA during failure situations.17 4.2.2.4 Signalling Connection Control Part User Adaptation Layer (SUA) .18 4.3 Architectural considerations STP network segment.18 4.4 Architectural considerations SEP access segme
11、nt22 4.4.1 Quasi-associated signalling.24 4.4.2 Associated signalling 25 4.5 Architectural considerations database segment 28 4.6 Security considerations.30 Annex A (informative): Graphical representation of interworking scenarios32 Annex B (informative): Bibliography.33 History 34 ETSI ETSI EG 202
12、360 V1.1.1 (2004-12) 4 Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314:
13、 “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no
14、 investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This ETSI Guide
15、 (EG) has been produced by ETSI Technical Committee Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN). Introduction The present document records the recommendations from ETSI Technical Committee TISPAN regarding the use of the different IETF SIGTRAN ad
16、aptation layer protocols in certain network scenarios. Especially it is intended to provide a guideline for network operators heading to introduce SS7 over IP. ETSI ETSI EG 202 360 V1.1.1 (2004-12) 5 1 Scope The present document summarizes guidelines regarding the application of adaptation layers or
17、iginally developed by IETF Work Group SIGTRAN and later on endorsed by ETSI. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or edition
18、number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Referen
19、ce. 1 ETSI TS 102 141: “Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP and SIGTRAN (Transport of SS7 over IP); Message transfer part 2 User Adaptation layer (M2UA) Endorsement of RFC 3331 (2002), modified“. 2 ETSI TS 102 142: “Services and Protocols for Advanced Networks (SPAN);
20、 MTP/SCCP/SSCOP and SIGTRAN (Message of SS7 over IP); Message transfer part 3 User Adaptation layer (M3UA) Endorsement of RFC 3332 (2002), modified“. 3 ETSI TS 102 143: “Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP and SIGTRAN (Transport of SS7 over IP); Signalling connection
21、control part User Adaptation layer (SUA) Endorsement of SIGTRAN-SUA-14 (December 2002), modified“. 4 ETSI TS 129 202: “Universal Mobile Telecommunications System (UMTS); Signalling System No. 7 (SS7) signalling transport in core network; Stage 3 (3GPP TS 29.202 version 5.2.0 Release 5)“. 5 I-D ACTIO
22、N draft-ietf-sigtran-m2pa-12.txt: “SS7 MTP2-User Peer-to-Peer Adaptation Layer“. 6 Implementors Guide (12/2000) for Recommendation Q.704 (07/96) published by ITU-T Study Group 11 COM 11-R 6-E January 2001. 7 ITU-T Recommendation Q.2210: “Message transfer part level 3 functions and messages using the
23、 services of ITU-T Recommendation Q.2140“. 8 ITU-T Recommendation Q.701: “Functional description of the message transfer part (MTP) of Signalling System No. 7“. 9 ITU-T Recommendation Q.702: “Signalling data link“. 10 ITU-T Recommendation Q.703: “Signalling link“. 11 ITU-T Recommendation Q.704: “Sig
24、nalling network functions and messages“. 12 ITU-T Recommendation Q.705: “Signalling network structure“. 13 ITU-T Recommendation Q.706: “Message transfer part signalling performance“. 14 ITU-T Recommendation Q.707: “Testing and maintenance“. 15 ITU-T Recommendation Q.708: “Assignment procedures for i
25、nternational signalling point codes“. 16 ITU-T Recommendation Q.709: “Hypothetical signalling reference connection“. ETSI ETSI EG 202 360 V1.1.1 (2004-12) 6 17 ITU-T Recommendation Q.2140: “B-ISDN ATM adaptation layer - Service specific coordination function for signalling at the network node interf
26、ace (SSCF AT NNI)“. 18 ETSI EN 300 008-1: “Integrated Services Digital Network (ISDN); Signalling System No.7; Message Transfer Part (MTP) to support international interconnection; Part 1: Protocol specification ITU-T Recommendations Q.701, Q.702, Q.703, Q.704, Q.705, Q.706, Q.707 and Q.708 modified
27、“. 19 ETSI EN 300 436-1: “Broadband Integrated Services Digital Network (B-ISDN); Signalling ATM Adaptation Layer (SAAL); Service Specific Connection Oriented Protocol (SSCOP); Part 1: Protocol specification ITU-T Recommendation Q.2110, modified“. 20 ETSI EN 301 004-1: “Broadband Integrated Services
28、 Digital Network (B-ISDN); Signalling System No.7; Message Transfer Part (MTP) level 3 functions and messages to support international interconnection; Part 1: Protocol specification ITU-T Recommendation Q.2210 (1996), modified“. 21 ETSI ETS 300 438-1: “Broadband Integrated Services Digital Network
29、(B-ISDN); Signalling ATM Adaptation Layer (SAAL); Service Specific Co-ordination Function (SSCF) for support of signalling at the Network Node Interface (NNI); Part 1: Specification of SSCF at NNI ITU-T Recommendation Q.2140 (1995), modified“. 22 ITU-T Recommendation Q.1901: “Bearer Independent Call
30、 Control protocol“. 23 ITU-T Recommendation H.248: “Gateway control protocol“. 24 IETF RFC 3436: “Transport Layer Security over Stream Control Transmission Protocol“. 25 IETF RFC 3332: “Signalling System 7 (SS7) Message Transfer Part 3 (MTP3) - User Adaptation Layer (M3UA)“. 26 ITU-T Recommendation
31、G.711: “Pulse code modulation (PCM) of voice frequencies“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: MTP-L3: general term for the functionality provided by MTP Level 3 when no details regarding special functio
32、nality to support lower layer functionality needs to distinguished MTP3: MTP-L3 functionality as defined by ITU-T Recommendation Q.704 along with support for narrowband TDM based SS7 links MTP3b: MTP-L3 functionality as defined by ITU-T Recommendation Q.2210 to support highspeed and broadband SS7 li
33、nks that require the exchange of longer sequence numbers in chase of change-over 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: AS Application Server ASP Application Server Process ATM Asynchronous Transfer Mode BLO Blocking message CCBS Call Completio
34、n to Busy Subscriber IPSEP IP based Signalling End Point IPSP IP based Signalling Point ISDN Integrated Services Digital Network ISUP ISDN User Part ETSI ETSI EG 202 360 V1.1.1 (2004-12) 7 MGC Media Gateway Controller also referred to as Softswitch MSU Message Signal Unit SAAL Signalling ATM Adaptio
35、n Layer SCCP Signalling Connection Control Part SCP Service Control Point SEP Signalling End Point SG Signalling Gateway SGP Signalling Gateway Process SS7oIP SS7 over IP STP Signalling Transfer Point STPG Signalling Transfer Point Gateway SU Signal Units TDM Time Division Multiplex TfA Transfer All
36、owed (as defined in ITU-T Recommendation Q.704) TfP Transfer Prohibited (as defined in ITU-T Recommendation Q.704) TLS Transport Layer Security UP User Part (as defined in ITU-T Recommendation Q.704) UPU User Part Unavailable XCA Acknowledgement Changeover Order XCO Extended Changeover Order 4 Netwo
37、rk architectures using SS7 over IP 4.1 General architectural considerations To allow a structured approach for architectural considerations regarding the use of SIGTRAN adaptation layers, the following example SS7 network is used. It should be noted that the SS7 network is assumed to meet todays fix
38、ed and mobile network operators needs. The usage of SS7oIP for 3GPP scenarios is covered in the appropriate 3GPP specifications, TS 129 202 4. ETSI ETSI EG 202 360 V1.1.1 (2004-12) 8 STP STPSTPSTPSEPSEP SEPSEPe.g.SCPSEP Access SegmentSTP Network SegmentSEP AccessSegmentDatabase SegmentTDM based SS7
39、link setFigure 1: General SS7 network architecture This network could be formally subdivided into different segments, namely: SEP Access Segment connection of Signalling Endpoints (SEP) with each other. - associated signalling mode - connection of Signalling Endpoints (SEP) with Signalling Transfer
40、Points (STP). - quasi-associated signalling mode - STP Network Segment connection between the Signalling Transfer Points (STP). Database Segment connection between the Signalling Transfer Points (STP) and specialized SS7 nodes providing functions for the Intelligent Network or Mobile Network. This p
41、artitioning is introduced to reflect the fact that some of the protocols out of the SIGTRAN suite have been designed to serve highly specialized scenarios. Table 1 summarizes requirements for introduction of SS7 over IP in existing SS7 networks. The requirement “stepwise introduction of SS7oIP“ is t
42、o ensure that there is no impact on the SS7 network parts that do not migrate from continued use of a circuit based network to an IP based network. Only bilateral agreements between the effected nodes are acceptable. The requirement “SI independency“ is to ensure that the introduction of SS7oIP does
43、 not introduce different signalling paths for signalling messages belonging to different MTP User Parts between any two signalling nodes. ETSI ETSI EG 202 360 V1.1.1 (2004-12) 9 The requirement “seamless interworking between SS7 link sets“ is to ensure that nodes having only conventional SS7 links c
44、an coexist with nodes using SS7oIP in the same MTP network without causing interoperability problems. An “X“ in table 1 indicates that the corresponding requirement is considered essential. An “-“ indicates that the corresponding requirement is not considered essential. Table 1: Requirements for int
45、roduction of SS7 over IP in existing SS7 networks Requirement SEP Access Segment STP network segment Database segment SEP to SEP SEP to STP stepwise introduction of SS7oIP X X X Xprovide SI independency X (see note 1)seamless interworking between SS7 link sets (see note 2) X X X NOTE 1: Only SCCP me
46、ssages are used to communicate with nodes in the database segment. NOTE 2: An SEP is not transferring incoming messages from one link/link set to another one. 4.2 General protocol aspects 4.2.1 SS7 protocol stack in TDM/ATM networks The conventional SS7 protocol stack as defined by ITU-T in Recommen
47、dations Q.701 8 up to Q.709 16, Q.2210 7, Q.2140 17 and modified by ETSI in EN 300 008-1 18, EN 300 436-1 19, EN 301 004-1 20 and ETS 300 438-1 21 is shown below. MTP3 (Q.704) or MTP3b (Q.2210)MTP- L2MTP- L1ISUP SCCPother MTP User PartsMTP- L2(Annex A)MTP- L1SSCF-NNISSCOPTCTC-user TC-userATMFigure 2
48、: SS7 Protocol stack (TDM and ATM transport protocols only) It is important to recognize that usage of the high speed option (annex A of ITU-T Recommendation Q.703 10) and the ATM based protocols using the SAAL protocol stack require the use of MTP3b according to ITU-T Recommendation Q.2210 7 (EN 30
49、1 004-1 20) to accommodate the usage of longer sequence numbers carried in XCO and XCA messages. An SEP with MTP3 according to ITU-T Recommendation Q.704 11 will not be able to handle these messages, because they are not defined in ITU-T Recommendation Q.704 11. An STP will pass these messages on if received in transit. ETSI ETSI EG 202 360 V1.1.1 (2004-12) 104.2.2 SS7 protocol stack in TDM/ATM and IP networks 4.2.2.1 MTP2-User Peer-to-Peer Adaptation Layer (M2PA) Th
