ETSI TS 123 205 V8.5.0 (2009-01) Technical Specification Universal Mobile Telecommunications System (UMTS); LTE; Bearer-independent circuit-switched core network; Stage 2 (3GPP TS 23.205 version 8.5.0 Release 8) 3GPP TS 23.205 version 8.5.0 Release 8 1 ETSI TS 123 205 V8.5.0 (2009-01) Reference RTS/TSGC-0423205v850 Keywords LTE, UMTS 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 à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). 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DECTTM, PLUGTESTSTM, UMTSTM, TIPHONTM, the TIPHON logo and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. LTE™ is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI 3GPP TS 23.205 version 8.5.0 Release 8 2 ETSI TS 123 205 V8.5.0 (2009-01) 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: "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 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 Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http://webapp.etsi.org/key/queryform.asp. ETSI 3GPP TS 23.205 version 8.5.0 Release 8 3 ETSI TS 123 205 V8.5.0 (2009-01) Contents Intellectual Property Rights................................................................................................................................2 Foreword.............................................................................................................................................................2 Foreword...........................................................................................................................................................15 1 Scope......................................................................................................................................................16 2 References..............................................................................................................................................16 3 Symbols and abbreviations.....................................................................................................................18 3.1 Symbols............................................................................................................................................................18 3.2 Abbreviations...................................................................................................................................................18 3.3 Definitions........................................................................................................................................................19 4 Main Concepts........................................................................................................................................19 4.1 General.............................................................................................................................................................19 4.2 Bearer-Independent Call Control.....................................................................................................................19 4.3 H.248/MEGACO..............................................................................................................................................20 5 General Circuit Switched Core Network Domain Architecture.............................................................20 5.1 Logical Architecture.........................................................................................................................................20 5.1.1 CS Core Network Nodes.............................................................................................................................20 5.1.1.1 MSC Server...........................................................................................................................................20 5.1.1.2 GMSC Server........................................................................................................................................20 5.1.1.3 Media Gateway.....................................................................................................................................20 5.1.2 CS Core Network Interfaces and Reference Points....................................................................................21 5.1.2.1 Mc Interface..........................................................................................................................................21 5.1.2.2 Nc Interface...........................................................................................................................................21 5.1.2.3 Nb Interface...........................................................................................................................................21 5.2 Network Interworking......................................................................................................................................21 5.2.1 Interworking on the Nc Reference Point.....................................................................................................21 5.2.2 Interworking on the Nb Reference Point....................................................................................................21 6 Call Establishment..................................................................................................................................21 6.1 Basic Mobile Originating Call..........................................................................................................................21 6.1.1 Forward bearer establishment.....................................................................................................................21 6.1.1.1 MGW selection.....................................................................................................................................21 6.1.1.2 Initial addressing...................................................................................................................................22 6.1.1.3 Network side bearer establishment.......................................................................................................22 6.1.1.4 Access bearer assignment.....................................................................................................................22 6.1.1.5 Framing protocol initialisation..............................................................................................................22 6.1.1.6 Confirmation of bearer establishment.............................................................................................22 6.1.1.7 Through-Connection.............................................................................................................................23 6.1.1.8 Interworking function............................................................................................................................23 6.1.1.9 Codec handling.....................................................................................................................................23 6.1.1.10 Voice Processing function.....................................................................................................................23 6.1.1.11 Failure handling in MSC server............................................................................................................23 6.1.1.12 Example................................................................................................................................................23 6.1.2 Backward bearer establishment..................................................................................................................26 6.1.2.1 MGW selection.....................................................................................................................................26 6.1.2.2 Network side bearer establishment.......................................................................................................26 6.1.2.3 Initial addressing...................................................................................................................................26 6.1.2.4 Access bearer assignment.....................................................................................................................27 6.1.2.5 Framing protocol initialisation..............................................................................................................27 6.1.2.6 Confirmation of bearer establishment...................................................................................................27 6.1.2.7 Through-Connection.............................................................................................................................27 6.1.2.8 Interworking function............................................................................................................................27 6.1.2.9 Codec handling.....................................................................................................................................28 6.1.2.10 Voice Processing function.....................................................................................................................28 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 4 ETSI TS 123 205 V8.5.0 (2009-01) 6.1.2.11 Failure handling in MSC server............................................................................................................28 6.1.2.12 Example................................................................................................................................................28 6.1.3 Originating Call Establishment For Iu Interface on IP...............................................................................30 6.1.4 Forward bearer establishment with Trace Session Activation....................................................................31 6.1.4.1 Trace activation.....................................................................................................................................31 6.1.4.2 Example................................................................................................................................................32 6.1.5 Originating Call Establishment for A interface over IP..............................................................................34 6.2 Basic Mobile Terminating Call........................................................................................................................35 6.2.1 Forward bearer establishment.....................................................................................................................35 6.2.1.1 GMSC server.........................................................................................................................................35 6.2.1.1.1 MGW selection................................................................................................................................35 6.2.1.1.2 Initial addressing.............................................................................................................................36 6.2.1.1.3 Outgoing side bearer establishment.................................................................................................36 6.2.1.1.4 Incoming side bearer establishment.................................................................................................36 6.2.1.1.5 Framing protocol initialisation........................................................................................................36 6.2.1.1.6 Through-Connection........................................................................................................................36 6.2.1.1.7 Confirmation of bearer establishment.............................................................................................36 6.2.1.1.8 Voice Processing function...............................................................................................................37 6.2.1.1.9 Failure handling in GMSC server....................................................................................................37 6.2.1.2 MSC server...........................................................................................................................................37 6.2.1.2.1 Paging..............................................................................................................................................37 6.2.1.2.2 Call setup.........................................................................................................................................37 6.2.1.2.3 MGW selection................................................................................................................................37 6.2.1.2.4 Network side bearer establishment..................................................................................................37 6.2.1.2.5 Access bearer assignment................................................................................................................37 6.2.1.2.6 Framing protocol initialisation........................................................................................................38 6.2.1.2.7 Called party alerting........................................................................................................................38 6.2.1.2.8 Called party answer.........................................................................................................................38 6.2.1.2.9 Through-Connection........................................................................................................................38 6.2.1.2.10 Interworking function......................................................................................................................39 6.2.1.2.11 Codec handling................................................................................................................................39 6.2.1.2.12 Voice Processing function...............................................................................................................39 6.2.1.2.13 Failure handling in MSC server.......................................................................................................39 6.2.1.2.14 Example...........................................................................................................................................39 6.2.2 Backward bearer establishment..................................................................................................................42 6.2.2.1 GMSC server.........................................................................................................................................42 6.2.2.1.1 MGW selection................................................................................................................................42 6.2.2.1.2 Outgoing side bearer establishment.................................................................................................42 6.2.2.1.3 Initial addressing.............................................................................................................................42 6.2.2.1.4 Incoming side bearer establishment.................................................................................................42 6.2.2.1.5 Framing protocol initialisation........................................................................................................42 6.2.2.1.6 Through-Connection........................................................................................................................43 6.2.2.1.7 Confirmation of bearer establishment.............................................................................................43 6.2.2.1.8 Voice Processing function...............................................................................................................43 6.2.2.1.9 Failure handling in GMSC server....................................................................................................43 6.2.2.2 MSC server...........................................................................................................................................43 6.2.2.2.1 Paging..............................................................................................................................................43 6.2.2.2.2 Call setup.........................................................................................................................................43 6.2.2.2.3 MGW selection................................................................................................................................44 6.2.2.2.3 Network side bearer establishment..................................................................................................44 6.2.2.2.4 Access bearer assignment................................................................................................................44 6.2.2.2.5 Framing protocol initialisation........................................................................................................44 6.2.2.2.6 Called party alerting........................................................................................................................45 6.2.2.2.7 Called party answer.........................................................................................................................45 6.2.2.2.8 Through-Connection........................................................................................................................45 6.2.2.2.9 Interworking function......................................................................................................................45 6.2.2.2.10 Codec handling................................................................................................................................45 6.2.2.2.11 Voice Processing function...............................................................................................................45 6.2.2.2.12 Failure handling in MSC server.......................................................................................................45 6.2.2.2.13 Example...........................................................................................................................................45 6.2.3 Terminating Call Establishment For Iu Interface on IP..............................................................................49 6.2.4 Terminating Call Establishment For A Interface over IP...........................................................................51 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 5 ETSI TS 123 205 V8.5.0 (2009-01) 7 Call Clearing..........................................................................................................................................51 7.1 Network Initiated..............................................................................................................................................52 7.1.1 GMSC server..............................................................................................................................................52 7.1.1.1 Call clearing from the incoming side....................................................................................................52 7.1.1.2 Call clearing to the outgoing side..........................................................................................................52 7.1.2 MSC server.................................................................................................................................................52 7.1.2.1 Call clearing from the network side......................................................................................................52 7.1.2.2 Call clearing to the UE..........................................................................................................................52 7.1.2.3 Example................................................................................................................................................53 7.2 User Initiated....................................................................................................................................................54 7.2.1 Void............................................................................................................................................................55 7.2.2 MSC server.................................................................................................................................................55 7.2.2.1 all clearing from the UE........................................................................................................................55 7.2.2.2 Call clearing to the network side...........................................................................................................55 7.2.2.3 Example................................................................................................................................................55 7.3 (G)MSC server Initiated...................................................................................................................................56 7.3.1 GMSC server..............................................................................................................................................56 7.3.1.1 Call clearing to the destination side......................................................................................................56 7.3.1.2 Call clearing to the originating side......................................................................................................56 7.3.2 MSC server.................................................................................................................................................57 7.3.2.1 Call clearing to the UE..........................................................................................................................57 7.3.2.2 Call clearing to the network side...........................................................................................................57 7.3.2.3 Example................................................................................................................................................57 7.4 MGW Initiated.................................................................................................................................................59 7.4.1 GMSC server..............................................................................................................................................59 7.4.1.1 Bearer released on the destination side.................................................................................................59 7.4.1.2 Bearer released on the originating side.................................................................................................59 7.4.2 MSC server.................................................................................................................................................59 7.4.2.1 Bearer released on the access side.........................................................................................................59 7.4.2.2 Bearer released on the network side......................................................................................................59 7.4.2.3 Example................................................................................................................................................59 7.5 Call Clearing for Iu Interface on IP..................................................................................................................61 8 Handover/Relocation..............................................................................................................................63 8.1 UMTS to UMTS...............................................................................................................................................63 8.1.1 Intra-MSC SRNS/SBSS Relocation...........................................................................................................63 8.1.1.1 Relocation Required..............................................................................................................................64 8.1.1.2 Relocation Command/Relocation Detect..............................................................................................64 8.1.1.3 Relocation Complete.............................................................................................................................64 8.1.1.4 Interworking function............................................................................................................................64 8.1.1.5 Codec handling.....................................................................................................................................64 8.1.1.6 Voice Processing function.....................................................................................................................64 8.1.1.7 Handling of multiple bearers (multicall)...............................................................................................64 8.1.1.8 Failure Handling in MSC server...........................................................................................................64 8.1.1.9 Example................................................................................................................................................64 8.1.2 Basic Inter-MSC SRNS/SBSS Relocation..................................................................................................67 8.1.2.1 MSC-A/MGW-A..................................................................................................................................67 8.1.2.1.1 Relocation Required........................................................................................................................67 8.1.2.1.2 Bearer establishment between MGW-A and MGW-B....................................................................67 8.1.2.1.3 Relocation Command/Relocation Detect........................................................................................67 8.1.2.1.4 Relocation Complete.......................................................................................................................67 8.1.2.1.5 Interworking function......................................................................................................................67 8.1.2.1.6 Codec handling................................................................................................................................67 8.1.2.1.7 Voice Processing function...............................................................................................................67 8.1.2.1.8 Handling of multiple bearers (multicall).........................................................................................68 8.1.2.1.9 Failure Handling in MSC server......................................................................................................68 8.1.2.2 MSC-B/MGW-B...................................................................................................................................68 8.1.2.2.1 MGW selection................................................................................................................................68 8.1.2.2.2 Bearer establishment towards RNC-B.............................................................................................68 8.1.2.2.3 Bearer establishment between MGW-A and MGW-B....................................................................68 8.1.2.2.4 Codec handling................................................................................................................................68 8.1.2.2.5 Voice Processing function...............................................................................................................68 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 6 ETSI TS 123 205 V8.5.0 (2009-01) 8.1.2.2.6 Handling of multiple bearers (multicall).........................................................................................68 8.1.2.2.7 Failure Handling in MSC server......................................................................................................68 8.1.2.2.8 Example...........................................................................................................................................69 8.1.3 Subsequent Inter-MSC SRNS/SBSS Relocation back to the Anchor MSC...............................................71 8.1.3.1 MSC-A/MGW-A..................................................................................................................................71 8.1.3.1.1 Relocation Request..........................................................................................................................71 8.1.3.1.2 Relocation Command/Relocation Detect........................................................................................71 8.1.3.1.3 Relocation Complete.......................................................................................................................72 8.1.3.1.4 Interworking function......................................................................................................................72 8.1.3.1.5 Codec handling................................................................................................................................72 8.1.3.1.6 Voice Processing function...............................................................................................................72 8.1.3.1.7 Handling of multiple bearers (multicall).........................................................................................72 8.1.3.1.8 Failure Handling in MSC server......................................................................................................72 8.1.3.2 MSC-B/MGW-B...................................................................................................................................72 8.1.3.2.1 Relocation Required........................................................................................................................72 8.1.3.2.2 Relocation Complete.......................................................................................................................72 8.1.3.2.3 Release of bearer towards MGW-A................................................................................................72 8.1.3.2.4 Handling of multiple bearers (multicall).........................................................................................73 8.1.3.2.5 Example...........................................................................................................................................73 8.1.4 Subsequent Inter-MSC SRNS/SBSS Relocation to a third MSC...............................................................75 8.1.5 SRNS/SBSS Relocation with Iu on IP........................................................................................................75 8.1.6 Intra-MSC enhanced SRNS Relocation......................................................................................................76 8.1.6.1 Introduction...........................................................................................................................................76 8.1.6.2 Enhanced Relocation Complete Request..............................................................................................76 8.1.6.3 Enhanced Relocation Complete Confirm..............................................................................................77 8.1.6.4 Interworking function............................................................................................................................77 8.1.6.5 Codec handling.....................................................................................................................................77 8.1.6.6 Voice Processing function.....................................................................................................................77 8.1.6.7 Handling of multiple bearers (multicall)...............................................................................................77 8.1.6.8 Failure Handling in MSC server...........................................................................................................77 8.1.6.9 Example................................................................................................................................................77 8.1.7 Intra-MSC enhanced SRNS Relocation with Iu on IP................................................................................79 8.2 UMTS to GSM.................................................................................................................................................80 8.2.1 Intra-MSC UMTS to GSM Handover.........................................................................................................80 8.2.1.1 Relocation Required..............................................................................................................................80 8.2.1.2 Handover Request Acknowledge..........................................................................................................81 8.2.1.3 Relocation Command/Handover Detect................................................................................................81 8.2.1.4 Handover Complete..............................................................................................................................81 8.2.1.5 Interworking function............................................................................................................................81 8.2.1.6 Voice Processing function.....................................................................................................................81 8.2.1.7 Handling of multiple bearers (multicall)...............................................................................................81 8.2.1.8 Failure Handling in MSC server...........................................................................................................81 8.2.1.9 Example................................................................................................................................................81 8.2.1.10 Intra-MSC UMTS to GSM Handover for A interface over IP..............................................................84 8.2.2 Basic Inter-MSC UMTS to GSM Handover...............................................................................................85 8.2.2.1 MSC-A/ MGW-A.................................................................................................................................85 8.2.2.1.1 Bearer establishment between MGW-A and MGW-B....................................................................85 8.2.2.1.2 Relocation Command/Handover Detect..........................................................................................85 8.2.2.1.3 Handover Complete.........................................................................................................................86 8.2.2.1.4 Interworking function......................................................................................................................86 8.2.2.1.5 Voice Processing function...............................................................................................................86 8.2.2.1.6 Handling of multiple bearers (multicall).........................................................................................86 8.2.2.1.7 Failure Handling in MSC server......................................................................................................86 8.2.2.2 MSC-B/MGW-B...................................................................................................................................86 8.2.2.2.1 MGW selection................................................................................................................................86 8.2.2.2.2 Bearer establishment towards BSC-B.............................................................................................86 8.2.2.2.3 Bearer establishment between MGW-A and MGW-B....................................................................86 8.2.2.2.4 Voice Processing function...............................................................................................................86 8.2.2.2.5 Failure Handling in MSC server......................................................................................................86 8.2.2.2.6 Example...........................................................................................................................................87 8.2.2.3 Basic Inter-MSC UMTS to GSM Handover for A Interface over IP....................................................89 8.2.3 Subsequent Inter-MSC UMTS to GSM Handover back to the Anchor MSC.............................................90 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 7 ETSI TS 123 205 V8.5.0 (2009-01) 8.2.3.1 MSC-A..................................................................................................................................................90 8.2.3.1.1 Handover Request...........................................................................................................................90 8.2.3.1.2 Handover Request Acknowledge....................................................................................................91 8.2.3.1.3 Relocation Command/Handover Detect..........................................................................................91 8.2.3.1.4 Handover Complete.........................................................................................................................91 8.2.3.1.5 Interworking function......................................................................................................................91 8.2.3.1.6 Voice Processing function...............................................................................................................91 8.2.3.1.7 Handling of multiple bearers (multicall).........................................................................................91 8.2.3.1.8 Failure Handling in MSC server......................................................................................................91 8.2.3.2 MSC-B..................................................................................................................................................91 8.2.3.2.1 Handover Complete.........................................................................................................................91 8.2.3.2.2 Release of bearer towards MGW-A................................................................................................91 8.2.3.2.3 Handling of multiple bearers (multicall).........................................................................................92 8.2.3.2.4 Example...........................................................................................................................................92 8.2.3.3 Subsequent Inter-MSC UMTS to GSM Handover back to the anchor MSC for A Interface over IP...........................................................................................................................................................94 8.2.4 Subsequent Inter-MSC UMTS to GSM Handover to a third MSC.............................................................95 8.3 GSM to UMTS.................................................................................................................................................95 8.3.1 Intra-MSC GSM to UMTS Handover.........................................................................................................96 8.3.1.1 Handover Required...............................................................................................................................96 8.3.1.2 Handover Command/Relocation Detect................................................................................................96 8.3.1.3 Relocation Complete.............................................................................................................................96 8.3.1.4 Interworking function............................................................................................................................96 8.3.1.5 Codec handling.....................................................................................................................................96 8.3.1.6 Voice Processing function.....................................................................................................................96 8.3.1.7 Failure Handling in MSC server...........................................................................................................96 8.3.1.8 Example................................................................................................................................................96 8.3.2 Basic Inter-MSC GSM to UMTS Handover...............................................................................................98 8.3.2.1 MSC-A..................................................................................................................................................99 8.3.2.1.1 Handover Required..........................................................................................................................99 8.3.2.1.2 Bearer establishment between MGW-A and MGW-B....................................................................99 8.3.2.1.3 Handover Command/Handover Detect............................................................................................99 8.3.2.1.4 Handover Complete.........................................................................................................................99 8.3.2.1.5 Interworking function......................................................................................................................99 8.3.2.1.6 Codec handling................................................................................................................................99 8.3.2.1.7 Voice Processing function...............................................................................................................99 8.3.2.1.8 Failure Handling in MSC server....................................................................................................100 8.3.2.2 MSC-B................................................................................................................................................100 8.3.2.2.1 MGW selection..............................................................................................................................100 8.3.2.2.2 Bearer establishment towards RNC-B...........................................................................................100 8.3.2.2.3 Bearer establishment between MGW-A and MGW-B..................................................................100 8.3.2.2.4 Codec handling..............................................................................................................................100 8.3.2.2.5 Voice Processing function.............................................................................................................100 8.3.2.2.6 Failure Handling in MSC server....................................................................................................100 8.3.2.2.7 Example.........................................................................................................................................101 8.3.3 Subsequent Inter-MSC GSM to UMTS Handover back to the Anchor MSC...........................................103 8.3.3.1 MSC-A................................................................................................................................................103 8.3.3.1.1 Handover Request.........................................................................................................................103 8.3.3.1.2 Handover Command/Relocation Detect........................................................................................104 8.3.3.1.3 Relocation Complete.....................................................................................................................104 8.3.3.1.4 Interworking function....................................................................................................................104 8.3.3.1.5 Codec handling..............................................................................................................................104 8.3.3.1.6 Voice Processing function.............................................................................................................104 8.3.3.1.7 Failure Handling in MSC server....................................................................................................104 8.3.3.2 MSC-B / MGW-B...............................................................................................................................104 8.3.3.2.1 Handover Required........................................................................................................................104 8.3.3.2.2 Handover Complete.......................................................................................................................105 8.3.3.2.3 Release of bearer towards MGW-A..............................................................................................105 8.3.3.2.4 Example.........................................................................................................................................105 8.3.4 Subsequent Inter-MSC GSM to UMTS Handover to a third MSC...........................................................107 8.3.5 GSM to UMTS Handover with Iu on IP...................................................................................................108 8.4 GSM to GSM.................................................................................................................................................109 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 8 ETSI TS 123 205 V8.5.0 (2009-01) 8.4.1 Intra-MSC Inter-BSS GSM to GSM Handover........................................................................................109 8.4.1.1 Handover Required.............................................................................................................................109 8.4.1.2 Handover Request Acknowledge........................................................................................................110 8.4.1.3 Handover Command/Handover Detect...............................................................................................110 8.4.1.4 Handover Complete............................................................................................................................110 8.4.1.5 Interworking function..........................................................................................................................110 8.4.1.6 Voice Processing function...................................................................................................................110 8.4.1.7 Failure Handling in MSC server.........................................................................................................110 8.4.1.8 Example..............................................................................................................................................111 8.4.1.9 Intra-MSC GSM to GSM Handover for A interface over IP..............................................................113 8.4.2 Basic Inter-MSC GSM to GSM Handover...............................................................................................114 8.4.2.1 MSC-A / MGW-A..............................................................................................................................114 8.4.2.1.1 Bearer establishment between MGW-A and MGW-B..................................................................114 8.4.2.1.2 Handover Command/Handover Detect..........................................................................................114 8.4.2.1.3 Handover Complete.......................................................................................................................115 8.4.2.1.4 Interworking function....................................................................................................................115 8.4.2.1.5 Voice Processing function.............................................................................................................115 8.4.2.1.6 Failure Handling in MSC server....................................................................................................115 8.4.2.2 MSC-B / MGW-B...............................................................................................................................115 8.4.2.2.1 MGW selection..............................................................................................................................115 8.4.2.2.2 Bearer establishment towards BSC-B...........................................................................................115 8.4.2.2.3 Bearer establishment between MGW-A and MGW-B..................................................................115 8.4.2.2.4 Voice Processing function.............................................................................................................115 8.4.2.2.5 Failure Handling in MSC server....................................................................................................115 8.4.2.2.6 Example.........................................................................................................................................115 8.4.2.3 Basic Inter-MSC GSM to GSM Handover for A Interface over IP....................................................118 8.4.3 Subsequent Inter-MSC GSM to GSM Handover back to the Anchor MSC.............................................119 8.4.3.1 MSC-A / MGW-A..............................................................................................................................119 8.4.3.1.1 Handover Request Acknowledge..................................................................................................119 8.4.3.1.2 Handover Command/Handover Detect..........................................................................................120 8.4.3.1.3 Handover Complete.......................................................................................................................120 8.4.3.1.4 Interworking function....................................................................................................................120 8.4.3.1.5 Voice Processing function.............................................................................................................120 8.4.3.1.6 Failure Handling in MSC server....................................................................................................120 8.4.3.2 MSC-B/MGW-B.................................................................................................................................120 8.4.3.2.1 Handover Complete.......................................................................................................................120 8.4.3.2.2 Release of bearer towards MGW-A..............................................................................................120 8.4.3.2.3 Example.........................................................................................................................................120 8.4.3.3 Subsequent Inter-MSC GSM to GSM Handover back to the anchor MSC for A Interface over IP...124 8.4.4 Subsequent GSM to GSM Handover to a third MSC...............................................................................124 8.5 Handling of GSM Services after UMTS to GSM Handover..........................................................................125 8.4.6 BSS Internal Handover.............................................................................................................................125 8.4.6.1 Introduction.........................................................................................................................................125 8.4.6.2 Internal Handover Required................................................................................................................125 8.4.6.3 Internal Handover Command/Handover Detect..................................................................................125 8.4.6.4 Handover Complete............................................................................................................................125 8.4.6.5 Interworking function..........................................................................................................................125 8.4.6.6 Voice Processing function...................................................................................................................125 8.4.6.7 Failure Handling in MSC server.........................................................................................................126 8.4.6.8 Example for a successful BSS Internal Handover...............................................................................126 9 Compatibility Issues.............................................................................................................................128 9.1 Interworking with GERAN (A i/f).................................................................................................................128 9.1.1 Introduction...............................................................................................................................................128 9.1.2 A interface over TDM...............................................................................................................................129 10 General (G)MSC server-MGW Procedures.........................................................................................129 10.1 MGW Unavailable.........................................................................................................................................129 10.2 MGW Available.............................................................................................................................................130 10.3 MGW Recovery.............................................................................................................................................131 10.4 (G)MSC server Recovery...............................................................................................................................132 10.4.1 General......................................................................................................................................................132 ETSI 3GPP TS 23.205 version 8.5.0 Release 8 9 ETSI TS 123 205 V8.5.0 (2009-01) 10.4.2 (G)MSC Server Restoration......................................................................................................................133 10.5 MGW Re-register...........................................................................................................................................133 10.6 MGW Re-registration Ordered by (G)MSC server........................................................................................134 10.7 Removal from Service of a Physical Termination..........................................................................................134 10.8 Restoration to Service of a Physical Termination..........................................................................................135 10.9 Audit of MGW...............................................................................................................................................135 10.9.1 Audit of Value..........................................................................................................................................135 10.9.2 Audit of Capability...................................................................................................................................136 10.10 MGW Capability Change...............................................................................................................................136 10.11 Void................................................................................................................................................................137 10.12 (G)MSC Server Out of service.......................................................................................................................137 10.13 MGW Resource Congestion Handling - Activate..........................................................................................137 10.14 MGW Resource Congestion Handling -Indication.........................................................................................137 10.15 Control association monitoring......................................................................................................................138 10.16 Hanging termination detection.......................................................................................................................138 11 Identities...............................................................................................................................................139 11.1 Bearer Address and Binding Reference..........................................................................................................139 11.2 MGW-Id.........................................................................................................................................................139 11.3 (G)MSC server Address.................................................................................................................................139 12 Operational Aspects.............................................................................................................................139 12.1 Charging.........................................................................................................................................................139 13 Interactions with Other Services..........................................................................................................139 13.1 Enhanced Multi-Level Precedence and Pre-emption service (eMLPP)..........................................................140 13.2 Call Deflection Service..................................................................................................................................140 13.2.1 MGW selection and incoming side bearer establishment.........................................................................140 13.2.2 IU/A-interface release...............................................................................................................................140 13.2.3 Notification to the Calling Subscriber......................................................................................................140 13.2.4 Initial addressing.......................................................................................................................................140 13.2.5 Establishment of bearer towards the forwarded-to subscriber..................................................................140 13.2.6 Failure handling in MSC server................................................................................................................140 13.2.7 Example....................................................................................................................................................140 13.3 Line identification Services............................................................................................................................142 13.3.1 Calling Line Identification Presentation (CLIP).......................................................................................142 13.3.2 Calling Line Identification Restriction (CLIR).........................................................................................142 13.3.3 Connected Line Identification Presentation (COLP)................................................................................142 13.3.4 Connected Line Identification Restriction (COLR)..................................................................................142 13.4 Call Forwarding Services...............................................................................................................................142 13.4.1 Call Forwarding Unconditional (CFU).....................................................................................................142 13.4.1.1 MGW selection...................................................................................................................................142 13.4.1.2 Incoming side bearer establishment....................................................................................................142 13.4.1.3 Notification to the Calling Subscriber.................................................................................................142 13.4.1.4 Initial addressing.................................................................................................................................142 13.4.1.5 Establishment of bearer towards the forwarded-to subscriber............................................................143 13.4.1.6 Confirmation of bearer establishment.................................................................................................143 13.4.1.7 Failure handling in GMSC server.......................................................................................................143 13.4.1.8 Example..............................................................................................................................................143 13.4.2 Call Forwarding on mobile subscriber Busy (CFB).................................................................................144 13.4.2.1 Network Determined User Busy (NDUB)..........................................................................................144 13.4.2.1.1 MGW selection..............................................................................................................................144 13.4.2.1.2 Incoming side bearer establishment...............................................................................................144 13.4.2.1.3 Notification to the calling subscriber.............................................................................................144 13.4.2.1.4 Initial addressing...........................................................................................................................145 13.4.2.1.5 Establishment of bearer towards the forwarded-to subscriber.......................................................145 13.4.2.1.5 Confirmation of bearer establishment...........................................................................................145 13.4.2.1.6 Failure handling in MSC server.....................................................................................................145 13.4.2.1.7 Example.........................................................................................................................................145 13.4.2.2 User Determined User Busy (UDUB).................................................................................................146 13.4.2.2.1 MGW selection..............................................................................................................................146 13.4.2.2.2 Incoming side bearer establishment...............................................................................................147 13.4.2.2.3 IU/A-interface release...................................................................................................................147 ETSI