ETRI Electronics and Telecommunication Research Institute SIP 중심의 Vo. IP 표준 기술 김 은숙 (eunah@etri. re. kr) ETRI / PEC 2003. 12. 10 인터넷 서비스&네트워크 보안 기술 워크샵
Contents § Introduction • Vo. IP & SIP § 관련 IETF WGs Status • SIP-WG • SIPPING-WG • XCON-WG • IMPP-WG & SIMPLE-WG § Summery 2 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
Introduction (1/2) § Vo. IP 표준기술 Application Layer w Call Intelligence w Service Creation /Execution w Mgmt of Provisioning App-Specific Application Platform Intra-App Protocols ISUP, Q. 931 H. 323, SIP+Others Signaling Layer w w Signaling Processing signaling Conversion Resource Management Bearer Control Signaling Platform Signaling Protocols TDM RTP FR ATM Media Layer w w media Processing Media Transport Qo. S Tones and Announcements Bearer Platform Media Transport 3 Application Platform Call Processing Protocols TAPI JTAPI etc Signalling Platform Media/ Bearer Control Protocols MGCP Megaco Bearer Platform 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
Introduction (2/2) § SIP (Session Initiation Protocol) • Multimedia session 설정, 유지, 종료를 위한 Signaling Protocol § 주요 Standard body에서의 SIP 채택 • 3 GPP (http: //www. 3 gpp. org) • Softswitch Consortium (http: //www. softswitch. org) • IMTC&ETSI TIPHON (http: //www. Imtc. org& http: //www. etsi. org/tiphon) - H. 323 -SIP interworking • Packet. Cable (http: //www. packetcable. com) - DCS (Distributed Call Signaling) • SIP Forum (http: //www. sipforum. org) • JAIN (http: //java. sun. com/products/jain/index. html) - JAVA API 4 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF Working Group Instant Messaging and Presence Protocol(impp) Applications Area SIP for IM and Presence Leveraging Extensions(simple) Internet Area Telephone Number Mapping (enum) Internet Emergency Preparedness (ieprep) Operations and Management Area IP Telephony (iptel) Routing Area Media Gateway Control (megaco) Middlebox Communication (midcom) Security Area Multiparty Multimedia Session Control (mmusic) Sub-IP Area PSTN and Internetworking (pint) Transport Area Signaling Transport (sigtran) Session Initiation Protocol (sip) User Services Area Session Initiation Proposal Investigation (sipping) Service in the PSTN/IN Requesting In. Ternet Service (spirits) Speech Service Control (speechsc) Centralized Conferencing (xcon) 5 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIP-WG (1/4) § WG Works • Core Protocol 수립 • SIPPING, SIMPLE 등의 작업 결과에 따른 Core Protocol 변경요구 수용 • 22 RFCs § WG Status • General - Original Milestone is already over - 58 th IETF : Milestone reset - 현재 Milestone 마무리되면 WG Closing 검토 • Technical - Method 확장 – PUBLISH, REFER, Join Header, etc. - Method 운영 변경 이슈 – – Non-INVITE Transaction Resource Priority, Congestion Safety (Connection Reuse) -> Encourage to use TCP GRUU - Service Enhancement 이슈 – RFC Update (Mobility 고려, GRUU 고려, etc. ) – Caller Preference / Callee Capability 6 – Security 강화 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIP-WG (2/4) § Non-Invite Transaction • Provisional response 전송 및 transaction timeout에 관련된 문제 • Race Condition 해결 Request E=T 1 Request Prv Response E=2*T 1 al Lost Fin 64*T 1 E=T 2 00 ok 2 nse Final Respo Non-Invite Race Condition Final Res Without Provisional Response 7 ponse With Provisional Response 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIP-WG (3/4) § Resource Priority • SIP을 통하여 IEPREP 작업 수행 관련 • Circuit-switched network, end system, proxy resource 선점해서 사용 하기 위한 요구사항 정리 • 긴급상황동안 PSTN이 Overloaded 될 때 call completion 가능성 높이는 목적 • Model - Short-term: 적정 게이트웨이로 라우팅을 강제적으로 설정하는 상황, 게이트웨 이가 일반 call과 ETS를 동시에 지원하도록 함 - Mid-term: 대부분의 Carrier들이 ETS 를 지원하는 상황, ETS는 별도로 처리 - Long-term: traveling-abroad-official model § Congestion Safety • SIP에서 UDP를 사용할 때 congestion 문제 발생 할 수 있음 - UDP 는 혼잡제어 제공 안함 - SIP 메시지가 hop 단위로 전송되는 것을 고려하여 hop 중간에 위치한 proxy가 TCP->UDP, 또는 UDP->TCP 변경하는 방법 제안 - Request 전송시 Congestion Safe Manner로 전송할 것 요청 8 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIP-WG (4/4) § Caller Preference / Callee Capability • Service 다양화 모색 • 사용자 관점의 요구사항 수용 NO ok - 사용자 별 선호도 및 수신 거부 여부 등록 - 사용자 별 수신 모드 변경 § 보안 강화 • • • NAT TLS S/MIME & AES (Advanced Encryption Standard) Authenticated Body History Info 9 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIPPING-WG (1/5) § WG Works • Application Requirements 수용 • SIP 코어 계정 요구시 SIP-WG으로 전달 • 6 RFCs § Specific Tasks of SIPPING WG • PSTN and/or 3 G telephony-equivalent applications that need a standardized approach • Messaging-like applications of SIP - support for hearing-/speech-impaired calling - usage guidelines for subscribe-notify • Multi-party applications of SIP • SIP calling to media servers § Works with • SIP, IPTEL, SIMPLE, AAA, MMUSIC, IEPREP 10 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIPPING-WG (2/5) § WG Status • General - Original Milestone is already over - 58 th IETF : Milestone reset - 현재 Milestone 마무리되어도 지속적 Charter 개정 예상됨 • Technical - Conferencing 관련 이슈 Operations관련 이슈 Management 관련 이슈 Media 관련 이슈 Emergency Call 관련 이슈 Security 관련 이슈 Service Examples/Call Control 11 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIPPING-WG (3/3) § Conference • Call Control 관련 이슈만 다룸 • Conference 제어 관련 : XCON-WG • 고려하는 Conference Model - End System Mixing Ad-hoc Centralizing Dial-In Conferencing Dial-Out Conferencing (1) INVITE/200/ACK (2)INVITE/200/ACK End System Mixing (10) 200 OK (11) ACK Conference Server (6) INVITE/200/ACK (8) (5) INVITE/200/ACK (9) INVITE (1) INVITE (2) 200 OK (3) ACK K AC 00/ /2 ITE R 200 INV REFE OK IFY/ 200 1) ) T E/ ( (3 ) 200) NO BY (4 (6 (7) (2) INVITE/200/ACK Conference Server (7 (5) (4) 20 ) NO 200 REF 0 O TI O E K FY K R (8) INVITE/200/ACK Dial-In Conferencing Ad-hoc Centralizing 12 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIPPING-WG (4/5) § Operations • Application Interaction - GRUU, KPML, Event Package, etc - DTMF를 Deliver하는 방법에 대한 논의 – HTML, WML, Voice. XML : Application Server 가 UA에 REFER 전송 – KPML : Application Server가 UA에게 SUBSCRIBE 전송 • SIP UA Configuration • Dual Stack Environments - IPv 6/IPv 4 동시 고려 : SDP관련 이슈 § Management 관련 • Torture Test • Load Management - Proxy의 과부하 방지 -> REFER 메소드 등을 사용하여 콜 분산 • Event Throttle - 클라이언트가 이벤트에 등록(SUBSCRIBE)시 이벤트 횟수 제한 가능하도록 Tag 사용 13 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIPPING-WG (5/5) § Emergency Call • Network과 Resource 사용에 대한 priority 선점 • Hearing Impaired User고려하여 일반 EMC와 구별 방법 • Location Information - SIP에 지리적 위치정보 삽입 방법 § Security Related Issues • Role-based Authorization Requirements • NAT and Policy Issues - NAT 해결위해 Interactive Connectivity Establishment (ICE) 제안 – 어느것이 persistent connection을 가져야 하는 것인가를 프락시가 판단 할 수 있는가의 문제와 연관 - Session Policy – Service Provider가 세션에 대한 관점 주장하기 원할 경우 » SDP Modification을 통해 반영 » 데이터 encryption의 경우 동작 안함 » Proxy가 세션 Description 정보를 모두 가져야 하므로 Proxy 복잡도 증가 – 3 GPP 방법 채택 제안 » 클라이언트가 SDP와 INVITE 전송시 488로 거절한 뒤 허용된 미디어와 코덱 제 공 » Offer/Answer 모델 이용 or 추가 메커니즘 설계 => 현재의 2 pass로 갈 것 예상 14 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF XCON-WG (1/4) § WG Works • Centralized Conference를 위한 Conference 제어 • SIPPING-WG의 Conference Framework에 근거함 • 58 th IETF – 1 st WG 회의 § Work Scope • membership 관리 (authorization control mechanism) • Multiple media type을 위한 media "layout" or "topology" for (audio, video, text) 기술 • Conference 관련된 이벤트의 생성/변화에 대한 notification (예: a roster) • A basic floor control protocol • Peer-to-peer cascading conferences (one conference is a participant in another and vice versa) 15 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF XCON-WG (2/4) § Conference Architecture Scope XCON CPCP Conference Server Conference Policy Server (Membership & Media policy) DB Participant Focus SIP dialog Conference Notification Service Subscribe / Notify Scope PPING SI Media Server RTP 16 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF XCON-WG (3/4) § Out-of- Scope • • • Voting Multicast media (due to security concerns) Fully distributed conferences Loosely-coupled conferences (no central point of control) Far-end device control Protocol used between the conference controller and the mixer(s) • Capabilities negotiation of the mixer(s) • Master-slave cascaded conferences 17 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF XCON-WG (4/4) § Conference Policy Control • • Conference Lifespan Who can be participants (permissions) Who can do what for each participant (roles) Notification of conference membership (roster) § Media Policy Control • • Conference에서 어떻게 media를 combine, select, modify 할지 정의 Multiple media types: audio, video, IM, etc Result of floor control is an input How a topology is created, retrieved, and manipulated § Floor Control • Floor Definition - Conference 를 위한 Temporary permission - Participant가 그룹 자원 중 특정한 공유 자원 조작을 위하여 Access • Floor Control Protocol Operations - Floor creation (related to media policy) - Floor requesting, granting, and releasing 18 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF IMPP-WG (1/3) § WG Works • Instant Messaging and Presence Protocol 정의 - internet-scale end-user presence awareness, notification 및 instant messaging system을 위한 data format 및 architecture • primary focus is immediate end-user delivery • CPIM - IM과 online Presence를 위한 Semantics 과 data format 정의 – independent of underlying transport infrastructure - IM 시스템의 Interoperation을 위하여 IM과 online Presence 를 위한 Common Agreement 정의 - Focus on Interoperation - 서비스의 Consumer와 Provider 기술 - Abstract Syntax 를 사용하는 Parameter 정의 - Security Considerations 정의 § WG Status • DONE • 3 RFCs 19 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF IMPP-WG (2/3) § Presence Model (RFC 2778) 20 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF IMPP-WG (3/3) § IM Model (RFC 2778) 21 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IETF SIMPLE-WG § WG Works • SIP for Instant Messaging and Presence Leveraging - Generate Standard SIP Extensions for IM and Presence – compliant to the RFC 2779(IMPP Requirements) and CPIM – work within the framework for IMP described in RFC 2778 – cannot modify baseline SIP behavior or define a new version of SIP for IMP § WG Status • General - 58 th IETF: Milestone reset - No RFCs • Technical - Filtering - XCAP 22 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
Summery § What’s SIP for? • No more for a Simple 1: 1 Session • Extended SIP - PSTN and 3 G Telephony equivalent Application - Messaging-like Application (Messenger and Presence) - Emergency System (including Hearing-/speech-impaired calling) - Multi-party Application (Conference, Push to Talk, etc. ) - Core Signaling for NGN • Status - Done: Core Protocol Issues - To do – Security Requirements are Strong – Various Application Issues • Expectation - A Killer Application for NGN § Does (or Will) it show us the money? ? 23 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
Q&A § Thanks for your attention! § Any Questions? 24 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
Electronics and Telecommunication Research Institute ETRI Appendix
ITU-T SG 16 § http: //www. itu. int/ITU-T/studygroups/com 16/ § VDSL, PSTN, IN등에의 멀티미디어 시스템 활용방안 § ALL-IP Network에서의 Vo. IP 서비스를 위한 Multimedia Framework 설계 26 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
ETSI-TIPHON § ETSI: the European Telecommunication Standards Initiative • TIPHON (Telecommunication and Internet Protocol Harmonization over Networks) 설립 - to work on standardization of voice over the Internet http: //www. etsi. org/tiphon Based on H. 323 v 2 Issues – The service-level interworking between SCNs served by PSTN, ISDN or GSM networks, and emerging NGN – multi-network interworking, across multiple administrative and technology domains – The challenge of providing public communications services in a heterogeneous environment independent of circuit or packet based network 27 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
IMTC § International Multimedia Telecommunications Consortium • http: //www. imtc. org § Activity goals : • Promoting standards that enable real-time, rich-media communications • Identifying obstacles to ubiquitous utilization of multimedia products and services • Developing and submitting technology interoperability recommendations to ETSI, IETF, 3 GPP, ISO, ITU-T • Initiating scheduled interoperability test sessions between suppliers of rich-media products and services • Educating and promoting the business and consumer communities on the benefits and implementation of Multimedia products § Main achievement : Interop event 28 인터넷서비스&네트워크보안기술 웍샵, Dec. , 2003
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