T T A S t a n d a r d 정보통신단체표준 ( 국문표준 ) TTAK.KO /R1 개정일 : 2014 년 xx 월 xx 일 이동통신사업자간 VoLTE 서비스연동규격 VoLTE Interworking Specification among Korean

T T A S t a n d a r d TTAK.KO-06.0338/R1 개정일 : 2014 년 xx 월 xx 일 이동통신사업자간 VoLTE 서비스연동규격 VoLTE Interworking Specification among Korean MNOs

TTAK.KO-06.0338/R1 개정일 : 2014 년 xx 월 xx 일 이동통신사업자간 VoLTE 서비스연동규격 VoLTE Interworking Specification among Korean MNOs 본문서에대한저작권은 TTA 에있으며, TTA 와사전협의없이이문서의전체또는일부를상업적목적으로복제또는배포해서는안됩니다. Copyrightc Telecommunications Technology Association 20xx. All Rights Reserved.

서문 1. 표준의목적 본표준은한국이동통신사업자 3 개사 KT, LGU+, SK 텔레콤간의 VoLTE(Voice Over LTE, 이하 VoLTE ) 서비스연동을위한기술을핵심적인프로토콜및전송규격을 정의한다. 2. 주요내용요약 본표준은한국이동통신사업자들의 VoLTE 서비스연동구간에정의되는규격으로서버기능, 정보의흐름을규정한다. VoLTE 서비스연동을제공하기위한핵심적인프로토콜및전송프로토콜을정의하고사업자연동기능을정의한다. 또한국제표준및단체표준등과호환가능하도록정의하여상호연동성을보장한다. 3. 표준적용산업분야및산업에미치는영향 본표준은이동통신사업자간 VoLTE 서비스연동에있어사업자간규격의상이함으로인하여발생할수있는혼란을최소화하고 VoLTE 서비스기술의발전과관련응용서비스활성화에기여할것이다. 또한 VoLTE 서비스활성화에따른다른다양한부가서비스를제공할수있다. 사용자측면 : 고품질의음성 / 영상통화를할수있고다양한부가서비스를소비할수있다. 서비스사업자측면 : 고품질음성 / 영상통화서비스환경하에다양한부가서비스제공환경이조성됨으로써, 기존음성 / 영상통화와의차별화된서비스로가입자증가에따른수익증가와신뢰성있는서비스제공을통한효율적인네트워크자원을활용할수있다. 4. 참조표준 ( 권고 ) 4.1. 국외표준 ( 권고 ) - 해당사항없음. i TTAK.KO-06.0338/R1

4.2. 국내표준 - 해당사항없음. 5. 참조표준 ( 권고 ) 과의비교 5.1. 참조표준 ( 권고 ) 과의관련성 - 해당사항없음. 5.2. 참조한표준 ( 권고 ) 과본표준의비교표 - 해당사항없음. 6. 지식재산권관련사항 본표준의 지식재산권확약서 제출현황은 TTA 웹사이트에서확인할수있다. 본표준을이용하는자는이용함에있어지식재산권이포함되어있을수있으므로, 확인후이용한다. 본표준과관련하여접수된확약서이외에도지식재산권이존재할수있다. 7. 시험인증관련사항 7.1. 시험인증대상여부 - 해당사항없음. 7.2. 시험표준제정현황 - 해당사항없음. ii TTAK.KO-06.0338/R1

8. 표준의이력정보 8.1. 표준의이력 판수제정 개정일제정 개정내역 제 1 판 2013. 10. 10 제정 TTAK.KO-06.0338 제 2 판 20xx. xx. xx 개정 TTAK.KO-06.0338/R1 8.2. 주요개정사항 TTAK.KO-06.0338/R1 TTAK.KO-06.0338 비고 6.2 IBCF 필수요구사항 6.2 IBCF 필수요구사항 변경 7.1.2.2 re-invite Method - 추가 8.2.2 시나리오 2 : Forking model 8.2.2 시나리오 2 : Forking model 변경 8.16.2. 영상착신호에대한음성수락 - 추가 8.17. 영상 / 음성전환 8.17. 영상 / 음성전환변경 iii TTAK.KO-06.0338/R1

Preface 1. Purpose of Standard The purpose of this standard is to describe techniques for Voice Over LTE(hereinafter referred to as VoLTE ) service interworking between Korean mobile network operators(skt, KT, LGU+). The core protocols and the transmission specifications to provide VoLTE service interworking amongoperators are defined in this standard. 2. Summary of Contents This standard defines the server functions and the flow of information related to VoLTE service interworking section. Also, the core protocols and the transmission specifications to provide VoLTE service interworking and operator interworking functionalities are defined in this standard. Furthermore, this standard ensures the interoperability with international standards and specifications. 3. Applicable Fields of Industry and its Effect This standard will contribute to minimize confusion caused by the difference of VoLTE service specifications among operators, and to improve the VoLTE service technology and activate related application services. With the vitalization of VoLTE services, other various supplementary services are expected to be provided creating benefits for both users and operators as listed below; User side: high-quality voice/video call, etc. Operator side: increase in subscribers, revenue, and efficiency of network resource usage. iv TTAK.KO-06.0338/R1

4. Reference Standards (Recommendations) 4.1. International Standards (Recommendations) - None 4.2. Domestic Standards - None 5. Relationship to Reference Standards(Recommendations) 5.1. Relationship of Reference Standards - None 5.2. Differences between Reference Standard(Recommendation) and this Standard - None 6. Statement of Intellectual Property Rights IPRs related to the present document may have been declared to TTA. The information pertaining to these IPRs, if any, is available on the TTA Website. No guarantee can be given as to the existence of other IPRs not referenced on the TTA website. And, please make sure to check before applying the standard. v TTAK.KO-06.0338/R1

7. Statement of Testing and Certification 7.1. Object of Testing and Certification - None 7.2. Standards of Testing and Certification - None 8. History of Standard 8.1. Change History Edition Issued date Outline The 1st edition 2013. 10. 10 Established TTAK.KO-06.0338 The 2nd edition 20xx. xx. xx Revised TTAK.KO-06.0338/R1 8.2. Revisions TTAK.KO-06.0338/R1 TTAK.KO-06.0338 Remarks 6.2 IBCF Requirement 6.2 IBCF Requirement Modified 7.1.2.2 re-invite Method - Added 8.2.2 scenario 2 : Forking model 8.2.2 scenario 2 : Forking model Modified 8.16.2. Audio acceptance of the incoming video call - Added 8.17. Voice-Video Change 8.17. Voice-Video Change Modified vi TTAK.KO-06.0338/R1

목차 1. 개요... 1 2. 표준의구성및범위... 1 3. 참조표준 ( 권고 )... 1 4. 용어정의및약어... 1 5. VoLTE 서비스연동요구사항... 2 5.1. 부가서비스... 2 5.2. 미디어코덱... 4 5.3. 번호체계 (numbering plan)... 4 5.4. DTMF 전송... 4 5.5. SIP 필수헤더정의... 4 5.6. 세션프로토콜 SDP... 5 5.7. 발신망판단기준... 7 6. VoLTE 연동네트워크구성... 7 6.1. 이동통신사업자 VoLTE 네트워크구성도... 7 6.2. IBCF 필수요구사항... 7 7. VoLTE 기본호처리... 9 7.1. VoLTE 망간호처리 (VoLTE-to-VoLTE)... 9 7.2. 안내방송... 13 8. 부가서비스호처리... 17 8.1. 번호변경안내... 17 8.2. 조건부착신전환안내방송... 23 8.3. 개별통화수신거부... 31 8.4. 음성사서함... 33 8.5. 착신금지... 43 vii TTAK.KO-06.0338/R1

8.6. 통화연결음... 45 8.7. 비즈링... 52 8.8. 익명호수신거부... 52 8.9. T-ring 서비스... 55 8.10. 발신번호표시... 58 8.11. 발신번호확인... 62 8.12. 발신번호표시제한... 65 8.13. 착신전환... 67 8.14. 가상번호... 82 8.15. 통화중대기... 83 8.16. 영상통화... 88 8.17. 영상 / 음성전환... 91 부록 Ⅰ. 관련문헌... 94 viii TTAK.KO-06.0338/R1

Contents 1. Introduction... 1 2. Constitution and Scope... 1 3. Reference Standards(Recommendations)... 1 4. Terms, Definitions and Abbreviations... 1 5. VoLTE Service Interworking Requirement... 2 5.1. Supplementary Service... 2 5.2. Media Codec... 4 5.3. Numbering Plan... 4 5.4. DTMF Transmission... 4 5.5. SIP Mandatory Header Definition... 4 5.6. SDP Session Protocol... 5 5.7. Determining the Origination Network... 7 6. VoLTE Network Architecture for Interworking... 7 6.1. VoLTE Network Architecture... 7 6.2. IBCF Requirement... 7 7. VoLTE Call Flows... 9 7.1. VoLTE-to-VoLTE... 9 7.2. Announcement... 13 8. Supplementary Service Call Flows... 17 8.1. Announcement for Number Change... 17 8.2. Announcement for Communication Forwarding... 23 8.3. Barring of Individual Call... 31 8.4. Voice Mail... 33 8.5. Barring of All Incoming Call... 43 ix TTAK.KO-06.0338/R1

8.6. Customized Alerting Tone... 45 8.7. Biz Ring... 52 8.8. Barring of Anonymous Call... 52 8.9. T-ring Service... 55 8.10. Originating Identification Presentation... 58 8.11. Originating Identification Presentation (Always)... 62 8.12. Originating Identification Restriction... 65 8.13. Communication Forwarding... 67 8.14. Two Number Service... 82 8.15. Communication Waiting... 83 8.16. Video Call... 88 8.17. Voice-Video Change... 91 AppendixⅠ. Related Documents... 94 x TTAK.KO-06.0338/R1

이동통신사업자간 VoLTE 서비스연동규격 (VoLTE Interworking Specification among Korean MNOs) 1. 개요 VoLTE 서비스의장점인고품질음성통화는사업자에관계없이국내모든가입자들에게사업자간직접연동을통해보편적혜택을제공될필요가있다. 본표준은이동통신사업자간 IP/IMS(IP Multimedia Subsystem) 기술기반의 VoLTE 서비스직접연동을위한국내표준제정을목적으로한다. 본표준은이동통신사업자, 부가통신사업자, 이동단말제조사, 이동통신시스템제조사를대상으로하며, VoLTE 서비스를제공하기위한핵심적인요구사항, 서버및단말기의관련기능, 정보의흐름, 즉, 제어프로토콜및전송프로토콜을정의한다. 2. 표준의구성및범위 본표준은음성통화의기본호와부가서비스의사업자간연동규격으로구성되어 있다. 부가서비스에는영상통화및영상 / 음성전환등의영상관련부가서비스도포 함된다. 본표준은개별사업자에특화된기능및서비스에대해서는다루지않는다. 3. 참조표준 ( 권고 ) - 해당사항없음. 4. 용어정의및약어 4.1. 용어정의 4.1.1. IBCF(Interconnection Border Control Function) IMS 서비스사업자간망연동및전반적제어기능을제공하는시스템이다. 4.1.2. TAS(Telephony Application Server) IMS 에서사용자들사이의멀티미디어부가서비스를제공하는시스템이다. 1 TTAK.KO-06.0338/R1

4.2. 약어 3GPP 3rd Generation Partnership Project 3GPP2 3rd Generation Partnership Project 2 AMR-NB AMR-WB CSCF DTMF IBCF ICID IMS RCS SDP SIP TAS UE Adative Multi-Rage-Narrow Band Adative Multi-Rage-Wide Band Call Session Control Function Dual Tone Multi Frequency Interconnection Border Control Function IM CN(IP Multimedia Core Network) subsystem Charging Identifier IP Multimedia Subsystem Rich Communication Suite Session Description Protocol Session Initiation Protocol Telephony Application Server User Equipment 5. VoLTE 서비스연동요구사항 IMS 표준기술기반으로 VoLTE 서비스를제공하기위한일반적인지침문서가존재하고, 사업자의 IMS 망 / 서비스간로밍및연동을위한일반적인지침문서가있다. 그러나 VoLTE 기본호처리정도만정의되어있을뿐국내사업자들의주요부가서비스에대한규격은부재인상황이며, 망간연동구조도국내환경에맞게추가정의가필요하다. 5.1. 부가서비스 본표준에서정의하는 VoLTE 부가서비스는다음과같다. 2 TTAK.KO-06.0338/R1

< 표 5-1> VoLTE 부가서비스 대분류서비스명서비스설명 Early media 류 CID 류 기타 번호변경안내 조건부착신전환안내방송 개별통화수신거부 음성사서함 착신금지 통화연결음 비즈링 익명호수신거부 T-ring 발신번호표시 발신번호확인 발신번호표시제한 착신전환 가상번호 통화중대기 영상통화 변경된번호를알려주고변경된번호로통화를연결해주는착신가입형서비스 걸려오는전화를조건부 ( 통화중, 전원꺼짐, 무응답, 음영지역 ) 로원하는전화로자동연결하는서비스 수신자가등록한특정발신번호에서들어오는음성, 영상, 문자메시지 (SMS/MMS) 를차단할수있는착신가입형서비스 전원이꺼졌거나배터리가떨어졌을때또는통화가되지않는지역에있어전화를받을수없을때전화를건상대방의메시지를놓치지않고음성으로받을수있는서비스 걸려오는모든전화에대해수신을차단하는착신가입형서비스 착신자가등록한음원을발신자에게들려주는서비스 기업홍보및광고를위해사업주 ( 광고주 ) 가요청한음원을기업에소속된종사자들의통화연결음에설정하여발신자에게들려주는서비스 번호를숨기고걸려오는전화에대해전화연결을차단하는착신가입형서비스 통화연결음이나오기전에발신자에게징글사운드를들려주는서비스 발신가입자의번호를착신가입자의단말에표시해주는착신가입형서비스 발신번호가제한된호의발신번호를착신가입자의단말에표시해주는착신가입형서비스 발신가입자의발신번호를착신가입자의단말에표시하지않게해주는발신가입형서비스 무조건착신전환은착신가입자에게수신되는모든전화를지정된번호로착신전환시키는서비스이고, 조건부착신전환서비스는착신가입자의상태가통화중 / 전원 OFF/ 무응답 / 음영지역등과같은사유로호가실패되는경우미리지정한전환번호로새로운호가전환될수있도록하는서비스 가입자에게원래전화번호외에전화및문자서비스를수신할수있는또하나의가상번호를부여하는서비스 통화중에새로운전화가걸려오면전화가왔음을알려주어고객이통화중에도걸려오는모든전화를받을수있게하기위한서비스 영상통화서비스 영상 / 음성전환음성통화와영상통화를실시간으로전환할수있는서비스 3 TTAK.KO-06.0338/R1

5.2. 미디어코덱 아래미디어코덱을지원해야한다. < 표 5-2> 미디어코덱 분류 음성코덱 영상코덱 코덱정보 AMR-WB AMR-NB H.264 H.263 5.3. 번호체계 (numbering plan) IBCF 간에는 tel URI 를사용한다. 5.4. DTMF 전송 다. RFC2833 표준의 wideband 또는 narrowband telephone-event 방식을지원해야한 5.5. SIP 필수헤더정의 < 표 5-3> SIP 필수헤더정의 항목 INV INV_180 INV_200 ACK UPD UPD_200 BYE BYE_200 Call-ID Via From To CSeq Max-Forward Contact Accept-Contact Session-Expires Supported Require User-Agent P-Asserted-Identity P-Asserted-Service 4 TTAK.KO-06.0338/R1

5.6. 세션프로토콜 SDP 5.6.1. 음성호 (voice call) 5.6.1.1. 필수파라미터 (mandatory parameter) < 표 5-4> 음성호 SDP 필수파라미터 parameter value description m audio <port> RTP/AVP <fmt list> Dynamic payload type 사용 AS:41 b RS:0 RR:0 rtpmap:<payload type> AMR-WB/16000/1 AMR-WB Bandwidth efficient fmtp:<payload type> mode rtpmap:<payload type> AMR/8000/1 AMR-NB Bandwidth efficient fmtp:<payload type> mode a rtpmap:<payload type> AMR-WB/16000/1 fmtp:<payload type> octet-align=1 rtpmap:<payload type> telephone-event/16000 fmtp:<payload type> 0-15 rtpmap:<payload type> AMR/8000/1 fmtp:<payload type> octet-align=1 rtpmap:<payload type> telephone-event/8000 fmtp:<payload type> 0-15 sendrecv ptime:20 maxptime:<max packet time> AMR-WB octet-align mode Wideband DTMF AMR-NB octet-align mode Narrowband DTMF Packet time Maximum packet time 5.6.1.2. 선택파라미터 (optional parameter) < 표 5-5> 음성호 SDP 선택파라미터 parameter value description a fmtp:<payload type> mode-set=8; modechange-capability=2; max-red=220; fmtp:<payload type> mode-set=7; modechange-capability=2; max-red=220; AMR-WB optional parameters AMR-NB optional parameters 5 TTAK.KO-06.0338/R1

5.6.2. 영상호 (video call) 5.6.2.1. 필수파라미터 (mandatory parameter) < 표 5-6> 영상호 SDP 필수파라미터 parameter value description m video <port> RTP/AVP <fmt list> Dynamic payload type 사용 AS:768 b RS:0 RR:19200 rtpmap:<payload type> H264/90000 fmtp:<payload type> profile-level-id=42c016; packetization-mode=1; sprop-parameter-sets=z0lafukdwkmg,am4g4g== H.264 VGA Portrait a framesize:<payload type> 480-640 rtpmap:<payload type> H263/90000 fmtp:<payload type> profile=0; level=10; QCIF=2 H.263 QCIF Landscape framesize:<payload type> 176-144 sendrecv framerate:<frame rate> 5.6.2.2. 선택파라미터 (optional parameter) < 표 5-7> 영상호 SDP 선택파라미터 parameter value description a fmtp:<payload type> profile-level-id=42c016; packetization-mode=1; sprop-parametersets=z0lafukbqhsg,am4g4g== framesize:<payload type> 640-480 fmtp:<payload type> profile-level-id=42c00c; packetization-mode=1; sprop-parametersets=z0ladokhhti=,am4g4g== framesize:<payload type> 240-320 fmtp:<payload type> profile-level-id=42c00d; packetization-mode=1; sprop-parameter-sets=z0ladekcg/i=,am4g4g== framesize:<payload type> 320-240 H.264 VGA Landscape H.264 QVGA Portrait H.264 QVGA Landscape fmtp:<payload type> profile-level-id=42c00a; packetization-mode=1; H.264 QCIF Landscape 6 TTAK.KO-06.0338/R1

parameter value description sprop-parameter-sets=z0lacukficg=,am4g4g== framesize:<payload type> 176-144 5.7. 발신망판단기준 연동구간에서는과금정보를위한 P-Charging-Vector 헤더정보를이용하여발신망을판단한다. 도메인 ICID 길이 ( 최대치 ) SKT sktims.net 256 bytes KT ims.kt.com 256 bytes LG U+ lte-lguplus.co.kr 256 bytes 6. VoLTE 연동네트워크구성 6.1. 이동통신사업자 VoLTE 네트워크구성도 ( 그림 6-1) VoLTE 네트워크구성도 6.2. IBCF 필수요구사항 1. 사업자간 IBCF 상태체크는 Options Method 로한다. 2. 대국이 OPTIONS 를보내더라도대국으로부터 OPTIONS 송신에대한 200 OK 를수 신하지못하면대국이 down 된것으로판단한다. 7 TTAK.KO-06.0338/R1

3. IBCF는 Options 메시지수신시 Request URI에포함된 SIP URI를참조하여상태체크 Options 메시지여부를확인하고응답한다. ( 예 : OPTIONS sip:ibcf01.sktims.net;lr SIP/2.0) 4. IBCF 상태체크를위한 Options 메시지내 Max-Forward 값은 0 으로한다. 5. IBCF 상태체크를위한 Options 전송기능은 On/Off할수있도록한다 ( 선택사항이며, Off 상태에서는 Active 상태로관리 ). 6. IBCF는멀티피어 (multi-peer) 연동기능을지원해야한다 ( 피어 (peer) 10 개이상 ). 7. IBCF는멀티피어 (multi-peer) 연동시서비스별라우팅기능을지원해야한다. 8. IBCF는멀티피어 (multi-peer) 연동시 Weighted Load Balance 기능을지원해야한다. 9. 상기 Weighted Load Balance 기능에 Weight 설정시 0 도설정가능해야하며, 0 으로설정된피어 (peer) 로부터메시지수신시정상처리해야한다. 10. 상기 Weighted Load Balance 기능에서 Weight 설정이 1 로설정된피어 (peer) 로 Request를전송하여세션이연결된후, Weight 설정이 0 으로설정된피어 (Peer) 로부터 Subsequent Request 또는 Response 수신시정상처리해야한다. ( 상기동작시 Request 및응답메시지의 R/R 헤더및 Via 헤더는 Weight 설정이 0 인피어 (peer) 의주소가포함됨, 하기호처리 (Call Flow) 참조 ) 11. IBCF 간 SIP 호처리 (Call Flow) 에대해 TCP/IP로연동하는경우메시지를수신하는쪽에모든사이즈에대해처리가능해야한다. 12. VoLTE 서비스에대한모든미디어패킷은 TrGW를통하도록한다. 13. IBC 연동실패시기존 3G 연동구간을통해우회소통되어야한다. 14. 연동구간에는 SDP candidate attribute를전달하지않아야한다. 15. 연동구간에서 UICC 표준에따른 SDP imageattr attribute 수신시처리할수있어야한다. 8 TTAK.KO-06.0338/R1

VoLTE/RCS 출중계 VoLTE/RCS 입중계 IBCF#1 IBCF#2 Ex-IBCF Weight : 1 Weight : 0 IBCF#1 IBCF#2 Ex-IBCF Weight : 1 Weight : 0 Invite R/R : IBCF#2 Via : IBCF#2 180/200 Ack 180/200 R/R : IBCF#2 R/R : Ex-IBCF Via : Ex-IBCF Invite R/R : Ex-IBCF Via : Ex-IBCF Ack Update 200 200 Update Bye 200 200 Bye 200 Bye Bye 200 ( 그림 6-2) VoLTE/RCS 네트워크구성도 9 TTAK.KO-06.0338/R1

7. VoLTE 기본호처리 7.1. VoLTE 망간호처리 (VoLTE-to-VoLTE) 7.1.1. 호생성 Operator A Network Operator B Network user1@opera tora.net CSCF IBCF IBCF CSCF user2@opera torb.net 1. INVITE 2. INVITE 3. 100 Trying 5. 100 Trying 4. INVITE 7. 100 Trying 6. INVITE 8. INVITE 9. 100 Trying 10. 180 Ringing 12. 180 Ringing 11. 180 Ringing 13. 180 Ringing 14. 180 Ringing 15. 200 OK 17. 200 OK 16. 200 OK 18. 200 OK 19. 200 OK 20. ACK 21. ACK 22. ACK 23. ACK 24. ACK RTP ( 그림 7-1) VoLTE-to-VoLTE 호생성절차 ( 그림 7-1) VoLTE 호생성메시지절차에대한설명은아래와같다. 4. INVITE 메시지 (IBCF_A IBCF_B) INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac Supported: 100rel,timer Supported: early-session To: <tel:+82-1010002001> 10 TTAK.KO-06.0338/R1

User-Agent: operatora_volte Via: SIP/2.0/UDP 211.188.227.35:5072;branch=z9hG4bK%0%fd6fe502919622f_546f6 7. INVITE 100 Trying 메시지 (IBCF_A IBCF_B) SIP/2.0 100 TRYING To: <sip:01010002001@operatorb.net> CSeq: 1 INVITE Via: SIP/2.0/UDP 211.115.15.147:30000;branch=z9hG4bK%0%747053CD3E1813AFFFeA905FFB7F39A9.d41D8C D98F00b204E9800998eCf8427E Content-Length: 0 12. INVITE 180 Ringing 메시지 (IBCF_A IBCF_B) SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel To: <sip:01010002001@operatorb.net>;tag=33333444444 Via: SIP/2.0/UDP 211.115.15.147:30000;branch=z9hG4bK%0%747053CD3E1813AFFFeA905FFB7F39A9.d41D8C D98F00b204E9800998eCf8427E 17. INVITE 200 OK 메시지 (IBCF_A IBCF_B) SIP/2.0 200 OK Via: SIP/2.0/UDP 211.115.15.147:30000;branch=z9hG4bK%0%747053CD3E1813AFFFeA905FFB7F39A9.d41D8C D98F00b204E9800998eCf8427E To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 INVITE^M Content-Type: application/sdp Content-Length: 196 Session-Expires: 90;refresher=uac P-Asserted-Identity: sip:01022337000@lgt.co.kr Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> 22. INVITE ACK 메시지 (IBCF_A IBCF_B) ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 ACK Max-Forwards: 70 Content-Length: 0 11 TTAK.KO-06.0338/R1

7.1.2. 호갱신 Session update 는 UPDATE 메소드를사용하거나 re-invite 를사용할수있다. 두방법모두 Session-Expires 헤더를포함해야하며, refresher 파라미터는 offer 또는 answer 메시지에명시하여야한다 (5.5. 참조 ) 7.1.2.1. UPDATE Method Operator A Network Operator B Network user1@opera tora.net CSCF IBCF IBCF CSCF user2@opera torb.net RTP 25. UPDATE 26. UPDATE 27. UPDATE 28. UPDATE 29. UPDATE 30. 200 OK 32. 200 OK 31. 200 OK 33. 200 OK 34. 200 OK ( 그림 7-2) VoLTE-to-VoLTE 호갱신절차 (UPDATE) ( 그림 7-2) VoLTE 호갱신메시지절차에대한설명은아래와같다. 27. UPDATE 메시지 (IBCF_A IBCF_B) UPDATE sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 UPDATE Supported: timer Max-Forwards: 70 Content-Length: 0 Session-Expires: 90;refresher=uac Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> 32. UPDATE 200 OK 메시지 (IBCF_A IBCF_B) SIP/2.0 200 OK To: <sip:01010002001@operatorb.net>;tag=33333444444 12 TTAK.KO-06.0338/R1

CSeq: 1 UPDATE Session-Expires: 90;refresher=uac 13 TTAK.KO-06.0338/R1

7.1.2.2. re-invite Method Operator A Network Operator B Network user1@opera tora.net CSCF IBCF IBCF CSCF user2@opera torb.net 25. re-invite 26. re-invite 27. re-invite 28. re-invite 29. re-invite 30. 200 OK 32. 200 OK 31. 200 OK 33. 200 OK 34. 200 OK 35. ACK 36. ACK 37. ACK 38. ACK 39. ACK RTP ( 그림 7-3) VoLTE-to-VoLTE 호갱신절차 (re-invite) ( 그림 7-3) VoLTE 호갱신메시지절차에대한설명은아래와같다. 27. re-invite 메시지 (IBCF_A IBCF_B) INVITE sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac Supported: 100rel,timer 14 TTAK.KO-06.0338/R1

Supported: early-session To: <sip:01010002001@operatorb.net>;tag=33333444444 User-Agent: operatora_volte Via: SIP/2.0/UDP 211.188.227.35:5072;branch=z9hG4bK%0%fd6fe502919622f_546f6 37. INVITE 200 OK 메시지 (IBCF_A IBCF_B) SIP/2.0 200 OK Via: SIP/2.0/UDP 211.115.15.147:30000;branch=z9hG4bK%0%747053CD3E1813AFFFeA905FFB7F39A9.d41D8C D98F00b204E9800998eCf8427E To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 INVITE^M Content-Type: application/sdp Content-Length: 196 Session-Expires: 90;refresher=uac P-Asserted-Identity: sip:01022337000@lgt.co.kr Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> 7.1.3. 호종료 Operator A Network Operator B Network user1@opera tora.net CSCF IBCF IBCF CSCF user2@opera torb.net RTP 35. BYE 36. BYE 37. BYE 38. BYE 39. BYE 40. 200 OK 42. 200 OK 41. 200 OK 43. 200 OK 44. 200 OK ( 그림 7-4) VoLTE-to-VoLTE 호종료절차 15 TTAK.KO-06.0338/R1

( 그림 7-3) VoLTE 호종료 BYE 메시지에대한설명은아래와같다. 37. BYE 메시지 (IBCF_A IBCF_B) BYE sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 BYE Max-Forwards: 70 Content-Length: 0 42. BYE 200 OK 메시지 (IBCF_A IBCF_B) SIP/2.0 200 OK To: <sip:01010002001@operatorb.net>;tag=33333444444 CSeq: 1 BYE ㅇ호종료 Reason 헤더 BYE request 메시지를전송하는발신망은호실패에대한원인을타이동통신사의착 신망에제공하기위해아래와같은 Reason 헤더를추가하여전달한다. 아래정의된 Reason 헤더는이동통신사업자 3 개사가공통적으로사용하는 cause 값 이며정의되지않은원인으로호를종료할경우에는 unspecified 값을사용하도록한다. 구분 Reason 헤더 관련서비스 normal Reason: Q.850;cause=16;text= normal 정상종료 no_rtp Reason: Q.850;cause=34;text= no_rtp 단말 RTP 미수신 no_upd Reason: Q.850;cause=102;text= no_upd Session time out 발생 no_upd_fail abort_session unspecified Reason: Q.850;cause=98;text= no_upd_fail Reason: Q.850;cause=58;text= abort_session Reason: Q.850;cause=31;text= unspecified UPDATE request에대한 fail response 수신시호를즉시종료할경우단말의액세스망단절이확인된경우 3개사연동규격으로정해지지않은원인일경우 7.2. 안내방송 7.2.1. 음성호안내방송 16 TTAK.KO-06.0338/R1

음성호에대한안내방송은 early-media 처리를위해 Forking Model 또는 Earlysession Model 을사용하며, 발신단말이 100rel을지원하는경우안내방송송출주체는발신단말로전송할 183 메시지에 Require:100rel 을포함해야한다. 각이동통신사별안내방송송출주체의차이로인해동일안내방송이 2 회송출되거나미송출될경우, 각각다음과같이처리하여안내방송문제를해결한다. 7.2.1.1. 안내방송 2 회송출문제해결 발신망 / 착신망모두송출하는경우는착신망송출및 487 Request Terminated 메시 지로응답하도록하며, 그절차는다음과같다. Operator A Network Operator B Network user1@oper atora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@oper atorb.net 1. INVITE 2. INVITE 3. INVITE 4. INVITE 8. 183 Session Progress 7. 183 Session Progress 6. 183 Session Progress 5. 183 Session Progress (Require: 100rel) 9. PRACK 10. PRACK 11. PRACK Supported: 100rel 여부에따라포함여부결정 12.PRACK 14. 200 OK 13. 200 OK 16. 200 OK 15. 200 OK RTP 20. 487 Request Terminated 19. 487 Request Terminated 18. 487 Request Terminated 17. 487 Request Terminated ( 그림 7-5) 안내방송 2 회송출문제해결절차 7.2.1.2. 안내방송미송출문제해결 안내방송미송출의경우에는착신망에서는호실패원인을 ITU-T Q.850 cause 값 을 Reason 헤더의 cause 파라미터에설정하여발신망으로전송하고, 발신망에서는 cause 값을참조하여해당안내방송을송출하도록한다. SIP Reason 헤더구성은다음표와같다. ( 아래에러코드값은권고사항으로서반드시 17 TTAK.KO-06.0338/R1

맞출필요는없다.) < 표 7-1> SIP Reason 헤더구성 구분 에러코드 Reason 헤더 Unalloc Number(U) 404 Reason: Q.850;cause=1;text= Unallocated Number Busy(B) 486 Reason: Q.850;cause=17;text= User Busy Paging Timeout(T) 408 Reason: Q.850;cause=18;text= Paging Timeout No Answer(N) 480 Reason: Q.850;cause=19;text= No Answer Power Off(P) 480 Reason: Q.850;cause=20;text= Power Off 18 TTAK.KO-06.0338/R1

안내방송미송출문제해결을위한절차는다음과같다. Operator A Network Operator B Network user1@oper atora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@oper atorb.net 1. INVITE 2. INVITE 3. INVITE 4. INVITE 5. Error Response(4xx ~ 6xx) 6. Error Response(4xx~6xx) Reason: SIP;cause=xx,text= 7. Error Response(4xx~6xx) Reason: SIP;cause=xx,text= 8. 183 Session Progress 9. PRACK 10. 200 OK Supported: 100rel 여부에따라포함여부결정 RTP 11. Error Response(4xx~6xx) ( 그림 7-6) 안내방송미송출문제해결절차 7.2.1.3. 호거절안내방송 음성호에대한호거절안내방송은착신에서송출하며, 응답메시지는 487 메시지를 전송하도록한다. 호거절범주는다음과같다. 착신가입자에의한거절 지정번호필터링 착신금지 익명호수신거부 7.2.2. 영상호안내방송 VoLTE 영상호에대해서는연동구간내에서는안내방송을송출하지않고, 자사망에서오류응답메시지에포함된 Reason 헤더를참조하여해당안내방송을송출한다. 착신망에서는호실패원인에대한안내방송제공을위해아래와같은 Reason 헤더를발신망으로전달한다. 19 TTAK.KO-06.0338/R1

개별통화수신거부, 착신금지, 익명호수신거부에대해 Reason 헤더에 cause=21 을포함한다. SIP Reason 헤더구성은다음표와같다. ( 아래에러코드값은권고사항으로서반드시맞출필요는없다.) 참고 ) 영상호에대한안내방송을음성호에대한안내방송처럼착신망에서 early media 형태로제공하는것에대해서는추후필요시추가표준화할수있다. < 표 7-2> 영상호안내방송 Reason 헤더 구분 에러코드 Reason 헤더 Unalloc Number(U) 404 Reason: Q.850;cause=1;text= Unallocated Number Busy(B) 486 Reason: Q.850;cause=17;text= User Busy Paging Timeout(T) 408 Reason: Q.850;cause=18;text= Paging Timeout No Answer(N) 480 Reason: Q.850;cause=19;text= No Answer Power Off(P) 480 Reason: Q.850;cause=20;text= Power Off Call Reject 603 Reason: Q.850;cause=21;text= Call Reject 영상호안내방송송출절차는다음그림과같다. Operator A Network Operator B Network user1@oper atora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@oper atorb.net 1. INVITE 2. INVITE 3. INVITE 4. INVITE 5. Error Response(4xx ~ 6xx) 6. Error Response(4xx~6xx) Reason: SIP;cause=xx,text= 7. Error Response(4xx~6xx) Reason: SIP;cause=xx,text= 8. 183 Session Progress 9. PRACK 10. 200 OK Supported: 100rel 여부에따라포함여부결정 RTP 11. Error Response(4xx~6xx) ( 그림 7-7) 영상호안내방송절차 20 TTAK.KO-06.0338/R1

8. 부가서비스호처리 8.1. 번호변경안내 번호변경안내는변경된번호를알려주고변경된번호로통화를연결해주는착신가입형서비스이다. 가입옵션에따라 ARS, SMS 등으로변경된번호에대한안내를제공한다. 부가서비스호처리의경우안내방송후착신전환을하는것과동일하다. 안내방송을해야하는경우발신단말의 early-session 지원여부에따라다르게동작해야한다. 안내방송없는경우는기본호와동일하게동작한다. 표준에는안내방송이있는경우에대해서만기술한다. 21 TTAK.KO-06.0338/R1

8.1.1. 시나리오 1 : Early-session model Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@opera torb.net 1. INVITE Supported: 100rel Supported: early-session 2. INVITE 3. INVITE 8. 183 Session Progress 7. 183 Session Progress 6. 183 Session Progress 4. INVITE 5. 183 Session Progress Require: 100rel Require: early-session Content-Disposition: early-session 9. PRACK 10. PRACK 15. 200 OK 16. 200 OK 11. PRACK 14. 200 OK 12. PRACK 13. 200 OK RTP 22. 180 Ringing 21. 180 Ringing 20. 180 Ringing 19. 180 Ringing 17. INVITE 18. 180 Ringing 23. 200 OK 24. 200 OK 25. 200 OK 26. 200 OK 27. 200 OK 28. ACK 29. ACK 30. ACK 31. ACK 32. ACK RTP ( 그림 8-1) 번호변경안내서비스 (Early-session model) 호처리 22 TTAK.KO-06.0338/R1

( 그림 8-1) 호처리의각메시지에대한설명은아래와같다. 3. INVITE 메시지 A Network 에서 B Network 으로전송되는 INVITE 에 Supported: 100rel 과 Supported: early-session 헤더가포함된다. INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Session-Expires: 90;refresher=uac Supported: 100rel Supported: early-session Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 6. 183 Session Progress 메시지 Require: 100rel 과 Content-Disposition: early-session 헤더가포함되며, SDP 에는 early session 을위한 offer 가포함된다. SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Require: 100rel CSeq: 1 INVITE Session-Expires: 90;refresher=uac Content-Disposition: early-session Rseq: 1 P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 23 TTAK.KO-06.0338/R1

11. PRACK 메시지 SDP 에는 early session 을위한 answer 가포함된다. PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 274 14. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 20. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 0 25. 200 OK 메시지 SDP 에는 (regular) session 을위한 answer 가포함된다. SIP/2.0 200 OK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 24 TTAK.KO-06.0338/R1

30. ACK 메시지 ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=a CSeq: 1 ACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 8.1.2. 시나리오 2 : Forking-model Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@opera torb.net 1. INVITE (Supported: 100rel) 2. INVITE 3. INVITE 4. INVITE 6. 183 Session Progress 5. 183 Session Progress (Require: 100rel) 8. 183 Session Progress 7. 183 Session Progress 9. PRACK Supported: 100rel 여부에따라포함여부결정 10. PRACK 11. PRACK 12. PRACK 13. 200 OK 14. 200 OK 15. 200 OK 16. 200 OK RTP 17. INVITE 18. 180 Ringing 19. 180 Ringing 20. 180 Ringing 21. 180 Ringing 22. 180 Ringing 23. 200 OK 24. 200 OK 25. 200 OK 26. 200 OK 27. 200 OK 28. ACK 29. ACK 30. ACK 31. ACK 32. ACK RTP ( 그림 8-2) 번호변경안내서비스 (Forking-model) 호처리 25 TTAK.KO-06.0338/R1

3. INVITE 메시지 Network A 에서 Network B 로전송되는 INVITE 에 100rel 지원여부에따라 Supported: 100rel 헤더가포함될수있다. INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac (Supported: 100rel) Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 6. 183 Session Progress 메시지 발신단말의 100rel 지원여부와착신서버의 100rel 지원여부에따라 Require: 100rel 과 RSeq 헤더가포함될수있다. SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> (Require: 100rel) CSeq: 1 INVITE Session-Expires: 90;refresher=uac (Rseq: 1) P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 11. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 26 TTAK.KO-06.0338/R1

14. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 20. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=b Content-Type: application/sdp Content-Length: 0 25. 200 OK 메시지 SIP/2.0 200 OK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=b Content-Type: application/sdp Content-Length: 274 30. ACK 메시지 ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=b CSeq: 1 ACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 8.2. 조건부착신전환안내방송 조건부착신전환안내방송은걸려오는전화를조건부 ( 통화중, 전원꺼짐, 무응답, 음영지역 ) 상태로자동연결하는서비스이다. 27 TTAK.KO-06.0338/R1

음성안내방송후에다른전화로연결할경우 early-media 처리와 History-info 헤 더처리방식, cause 값 /reason text 에대한표준화가요구된다. 8.2.1. 시나리오 1 : Early-session model Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B User2/User3 @operatorb. net 1. INVITE Supported: 100rel Supported: early-session 2. INVITE 3. INVITE 4. INVITE 5. INVITE(To: User 2) 6. 180 Ringing 7. 180 Ringing 8. 180 Ringing 9. 180 Ringing 자동연결판단 10. 180 Ringing 11. 183 Session Progress 12. 183 Session Progress Require: 100rel Content-Disposition: early-session 13. 183 Session Progress 14. 183 Session Progress 15. PRACK 16. PRACK 17. PRACK 18. PRACK 19. 200 OK 20. 200 OK 21. 200 OK 22. 200 OK RTP 23. INVITE(To: User 3) 24. 181 Call Is Being Forwarded 25. 181 Call Is Being Forwarded 28. 180 Ringing 26. 181 Call Is Being Forwarded 29. 180 Ringing 27. 181 Call Is Being Forwarded 31. 180 Ringing 32. 180 Ringing 30. 180 Ringing 35. 200 OK 34. 200 OK 33. 200 OK 36. 200 OK 37. 200 OK 38. ACK 39. ACK 40. ACK 41. ACK 42. ACK RTP ( 그림 8-3) 조건부착신전환안내방송 (Early-session model) 호처리 28 TTAK.KO-06.0338/R1

3. INVITE 메시지 INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac Supported: 100rel Supported: early-session Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 7. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=33333444444 Via: SIP/2.0/UDP 211.115.15.147:30000;branch=z9hG4bK%0%747053CD3E1813AFFFeA905FFB7F39A9.d41D8C D98F00b204E9800998eCf8427E Content-Length: 0 12. 183 Session Progress 메시지 SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Require: 100rel Require: early-session CSeq: 1 INVITE Session-Expires: 90;refresher=uac Content-Disposition: early-session Rseq: 1 P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 29 TTAK.KO-06.0338/R1

17. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 431 Content-Type: application/sdp 20. 200 OK 메시지 SIP/2.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 25. 181 Call Is Being Forwarded 메시지 SIP/2.0 181 Call Is Being Forwarded Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Length: 0 30. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Length: 0 35. 200 OK 메시지 SIP/2.0 200 OK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 30 TTAK.KO-06.0338/R1

40. ACK 메시지 ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=a CSeq: 1 ACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 8.2.2. 시나리오 2 : Forking model Forking model로동작할때단말에서미디어업데이트가필요한경우에는바로이전 early media의 To-tag와다르게설정되어야한다. 그러나 181 Call Is Being Forwarded 메시지를받을때는단말에서미디어업데이트가필요하지않으므로, 181의 To-tag는이전또는이후 early media의 To-tag와같아도된다. 31 TTAK.KO-06.0338/R1

Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B User2/User3 @operatorb. net 1. INVITE (Supported: 100rel) 2. INVITE 3. INVITE 4. INVITE 5. INVITE(To: User 2) 6. 180 Ringing 7. 180 Ringing 8. 180 Ringing To: tel:+821012342222; tag=a 9. 180 Ringing 자동연결판단 10. 180 Ringing 11. 183 Session Progress 12. 183 Session Progress To: tel:+821012342222; tag=b (Require: 100rel) 13. 183 Session Progress 14. 183 Session Progress 15. PRACK Supported: 100rel 여부에따라포함여부결정 16. PRACK 17. PRACK 18. PRACK 19. 200 OK 20. 200 OK 21. 200 OK 22. 200 OK RTP 25. 181 Call Is Being Forwarded 26. 181 Call Is Being Forwarded 27. 181 Call Is Being Forwarded 30. 180 Ringing 31. 180 Ringing 32. 180 Ringing 35. 200 OK 36. 200 OK 37. 200 OK 34. 200 OK 23. INVITE(To: User 3) 24. 181 Call Is Being Forwarded To: tel:+821012342222; tag=b or B` (Require: 100rel) 29. 180 Ringing 28. 180 Ringing To: tel:+821012342222; tag=c 33. 200 OK To: tel:+821012342222; tag=d 38. ACK 39. ACK 40. ACK 41. ACK 42. ACK RTP ( 그림 8-4) 자동연결 (Forking model) 호처리 32 TTAK.KO-06.0338/R1

3. INVITE 메시지 INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac (Supported: 100rel) Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 8. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Length: 0 12. 183 Session Progress 메시지 SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> (Require: 100rel) CSeq: 1 INVITE Session-Expires: 90;refresher=uac (Rseq: 1) P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=b Content-Type: application/sdp Content-Length: 274 33 TTAK.KO-06.0338/R1

17. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=b CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 20. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=b CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 25. 181 Call Is Being Forwarded 메시지 SIP/2.0 181 Call Is Being Forwarded Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=b or B Content-Length: 0 30. 180 Ringing 메시지 SIP/2.0 180 Ringing Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=c Content-Length: 0 35. 200 OK 메시지 SIP/2.0 200 OK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=d Content-Type: application/sdp Content-Length: 274 34 TTAK.KO-06.0338/R1

40. ACK 메시지 ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=d CSeq: 1 ACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 8.3. 개별통화수신거부 개별통화수신거부는수신자가등록한특정발신번호에서들어오는음성, 영상, 문 자메시지 (SMS/MMS) 를차단할수있는착신가입형서비스이다. 음성통화차단후안 내방송을들려주므로안내방송기능외에특별한기능은필요하지않다. Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B User2/User3 @operatorb. net 1. INVITE (Supported: 100rel) 2. INVITE 3. INVITE 4. INVITE 5. 183 Session Progress 6. 183 Session Progress (Require: 100rel) 8. 183 Session Progress 7. 183 Session Progress 9. PRACK Supported: 100rel 여부에따라포함여부결정 10. PRACK 11. PRACK 12. PRACK 13. 200 OK 14. 200 OK 15. 200 OK 16. 200 OK RTP 18. 487 Request Terminated 17. 487 Request Terminated 20. 487 Request Terminated 19. 487 Request Terminated ( 그림 8-5) 개별통화수신거부호처리 35 TTAK.KO-06.0338/R1

3. INVITE 메시지 A Network 에서 B Network 으로전송되는 INVITE 메시지에 100rel 지원여부에따라 Supported: 100rel 헤더가포함될수있다. INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac (Supported: 100rel) Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte v= 6. 183 Session Progress 메시지 발신단말의 100rel 지원여부와착신서버의 100rel 지원여부에따라 Require: 100rel 과 RSeq 헤더가포함될수있다. SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> (Require: 100rel) CSeq: 1 INVITE Session-Expires: 90;refresher=uac (Rseq: 1) P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 v= 36 TTAK.KO-06.0338/R1

11. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 14. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 18. 487 Request Terminated 메시지 SIP/2.0 487 Request Terminated CSeq: 1 INVITE P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a 8.4. 음성사서함 음성사서함서비스는전원이꺼졌거나배터리가방전되었을때또는통화가되지않는지역에있어전화를받을수없을경우, 전화를건상대방의메시지를놓치지않고음성으로받을수있는서비스이다. SKT/KT/LGU+ 의서비스명칭은각각소리샘 / 음성사서함 / 음성사서함이다. 3사의음성사서함접속처리에따라상이한절차를가질수있다. SKT/KT는음성사서함접속시 Legacy(CS) 망을이용하여연동을하고 LGU+ 는 IMS 망을통해직접연동한다. 이를바탕으로아래와같은시나리오를생각할수있다. < 표 8-1> 음성사서함시나리오 시나리오 발신단말지원모델 착신사업자 시나리오 1 Early-session model KT/LGU+ 시나리오 2 Forking model SKT/KT/LGU+ 37 TTAK.KO-06.0338/R1

< 표 8-2> 이동통신사업자별 Early Media 처리모델 사업자 Early Media 처리모델특징 SKT KT LG U+ Early-session model Forking model Forking model Forking model - Forking model 미지원 - 183(early session) 이후 183(early session) - 183(early session) 이후 183(regular session) - 183(early session) 이후 200 OK - 183 내려올때항상 update - 200 OK에대해서는 To-tag가다를때만 update - 183의 To-tag가다르면항상 update - To-tag가동일하면 update 하지않음 - 183 이후 180이내려올때 To-tag가다르면 RBT 재생함 - 183의 To-tag가다르면항상 update - To-tag가동일하면 update 하지않음 38 TTAK.KO-06.0338/R1

8.4.1. 시나리오 1 : Early-session model 지원단말의음성사서함접속 Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@opera torb.net 1. INVITE Supported: 100rel Supported: early-session 2. INVITE 3. INVITE 4. INVITE 5. INVITE 판단 8. 183 Session Progress 9. 183 Session Progress 10. PRACK 11. PRACK 7. 183 Session Progress 6. 183 Session Progress Require: 100rel Content-Disposition: early-session 17. 200 OK 16. 200 OK 12. PRACK 15. 200 OK 13. PRACK 14. 200 OK RTP 21. 183 Session Progress 20. 183 Session Progress 19. 183 Session Progress 18. 183 Session Progress To: +821012342222; To-tag=C (Require: 100rel) 22. PRACK 23. PRACK 24. PRACK 28. 200 OK 29. 200 OK 27. 200 OK 25. PRACK 26. 200 OK 33. 200 OK 32. 200 OK 31. 200 OK 30. 200 OK 34. ACK 35. ACK 36. ACK 37. ACK RTP ( 그림 8-6) 음성사서함 (Early-session model) 호처리 39 TTAK.KO-06.0338/R1

3. INVITE 메시지 INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac Supported: 100rel Supported: early-session Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 7. 183 Session Progress 메시지 SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Require: 100rel Require: early-session CSeq: 1 INVITE Session-Expires: 90;refresher=uac Content-Disposition: early-session Rseq: 1 P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 12. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 431 Content-Type: application/sdp 40 TTAK.KO-06.0338/R1

15. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 19. 183 Session Progress 메시지 SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Require: 100rel CSeq: 1 INVITE Session-Expires: 90;refresher=uac Rseq: 1 P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 24. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 431 Content-Type: application/sdp 27. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 41 TTAK.KO-06.0338/R1

31. 200 OK 메시지 SIP/2.0 200 OK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY CSeq: 1 INVITE Session-Expires: 90;refresher=uac P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 36. ACK 메시지 ACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 To: <sip:01010002001@operatorb.net>;tag=a CSeq: 1 ACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 8.4.2. 시나리오 2 : Forking model 지원단말의음성사서함접속 음성사서함서버접속시 183 Session Progress 메시지를통해최종응답이전달될경우이후 200 OK 메시지는동일 dialog 내에존재해야한다. 즉, 단말에서미디어업데이트가필요없기때문에 183 Session Progress 와 200 OK 메시지의 To-tag는동일해야한다. 42 TTAK.KO-06.0338/R1

Operator A Network Operator B Network user1@opera tora.net IMS Core_A IBCF_A IBCF_B IMS Core_B user2@opera torb.net 1. INVITE (Supported: 100rel) 2. INVITE 3. INVITE 4. INVITE 9. 183 Session Progress 8. 183 Session Progress 7. 183 Session Progress 판단 6. 183 Session Progress 5. INVITE To: +821012342222; To-tag=A (Require: 100rel) 10. PRACK 11. PRACK 발신단말의 100rel 지원여부에따라포함여부결정 12. PRACK 13. PRACK 14. 200 OK 15. 200 OK 16. 200 OK 17. 200 OK RTP 21. 183 Session Progress 20. 183 Session Progress 19. 183 Session Progress 18. 183 Session Progress To: +821012342222; To-tag=B (Require: 100rel) 22. PRACK 발신단말의 100rel 지원여부에따라포함여부결정 23. PRACK 24. PRACK 25. PRACK 26. 200 OK 27. 200 OK 28. 200 OK 29. 200 OK 32. 200 OK 31. 200 OK 30. 200 OK To: +821012342222; To-tag=C 33. 200 OK 34. ACK 35. ACK 36. ACK 37. ACK RTP ( 그림 8-7) 음성사서함 (Forking model) 호처리 43 TTAK.KO-06.0338/R1

3. INVITE 메시지 A Network 에서 B Network 으로전송되는 INVITE 에 100rel 지원여부에따라 Supported: 100rel 헤더가포함될수있다. INVITE sip:01010002001@operatorb.net SIP/2.0 Accept-Contact: *;+g.3gpp.icsi-ref="urn%3aurn-7%3a3gppservice.ims.icsi.mmtel";require;explicit Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Content-Length: 431 Content-Type: application/sdp CSeq: 1 INVITE Max-Forwards: 66 Min-SE: 90 P-Asserted-Identity: <sip:01010001001@operatora.net> P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel P-Early-Media: supported Privacy: none Record-Route: <sip:th00so-tu03@220.103.220.244:5067;lr> Session-Expires: 90;refresher=uac (Supported: 100rel) Supported: timer To: <tel:+82-1010002001> User-Agent: operatora_volte 7. 183 Session Progress 메시지 발신단말의 100rel 지원여부와착신서버의 100rel 지원여부에따라 Require: 100rel 과 RSeq 헤더가포함될수있다. SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> (Require: 100rel) CSeq: 1 INVITE Session-Expires: 90;refresher=uac (Rseq: 1) P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=a Content-Type: application/sdp Content-Length: 274 12. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 44 TTAK.KO-06.0338/R1

15. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=a CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 19. 183 Session Progress 메시지 SIP/2.0 183 Session Progress Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> (Require: 100rel) CSeq: 1 INVITE Session-Expires: 90;refresher=uac (Rseq: 1) P-Asserted-Identity: <sip:01010002001@operatorb.net> To: <sip:01010002001@operatorb.net>;tag=b Content-Type: application/sdp Content-Length: 274 24. PRACK 메시지 PRACK sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net SIP/2.0 RAck: 1 1 INVITE To: <sip:01010002001@operatorb.net>;tag=b CSeq: 2 PRACK Contact: <sip:ibcf_a%1fuser1%1foperatora_net%1f@ibcf.operatora.net> Max-Forwards: 66 Content-Length: 0 27. 200 OK 메시지 SIP/20.0 200 OK To: <sip:01010002001@operatorb.net>;tag=b CSeq: 2 PRACK Contact: <sip:ibcf_b%1fuser2%1foperatorb_net%1f@ibcf.operatorb.net> Content-Length: 0 45 TTAK.KO-06.0338/R1