IPTV 망구조및진화모델 2007.2.8. Sunhee Yang 한국전자통신연구원 shyang@etri.re.kr shyang@etri.re.kr
Confusion in definition & tech. & standards depending on SPs Telco 입장에서. Transmitting Digital Digital Television Interactive and and Enriched Multimedia for for any any IP IP device device New New ways ways of of packaging contents Blending Communications and and Contents HQ HQ and and Efficiency in in the the transport of of IP IP and and MPEG MPEG traffic traffic Digital Cable Satellite Broadband Carriers Digital terrestrial Broadcasts IOC FG-IPTV NGNA DVB-MHP ISMA ATIS DSL Forum IPTV 2 shyang@etri.re.kr
2007 for IPTV? 단말 (X, Y, Z) 콘텐츠 (A, B, C) Srv Platform (D, E, F) Service Platform (A) F E S L3/L2 D Edge L3/L2 Edge SO LL AT M (A) (A) IRD Single vendor 에의한 e2e solution Integrator L 2 / L 3 2007 Interoperable, Integrated solutions open standard More than 기존서비스 1) 표준 : 핵심기술 Spec. - Codec - Contents Protection (DRM/CAS) - Middleware for interactive Service - Streaming protocol - 품질기준및측정 2) Right Infrastructure - Service Architecture for differentiated service 3) 핵심기술확보 - rmt configurable/downloadable SW Platform - QoS/QoE Measurement & Monitoring - IMS enabled IPTV - Mobile IPTV 핵심기술 & 표준대비 3 shyang@etri.re.kr
Contents 0. What? How? 뭐가문제인지.? 1. Review 2006(IPTV 기술현황 ) 2. Architecture & Challenging technologies 3. 진화전망 4. Discussion shyang@etri.re.kr
Facts of 1G IPTV IPTV 서비스제공현황및 Issues Future IPTV 370 사업자서비스중 (2006.2.) Independent Operating Company 위주 Major telco 투자진행중 (SBC, BT, Verizon) 주로소규모가입자대상 ( 지역서비스 ) 별도망 ( 예 : PCCW, FastWeb) 기존 TV 대체 + VoD 위주콘텐츠 비표준플랫폼 (Middleware,CAS/DRM) MPEG2-TS Microsoft IPTV Service Platform Issues of 1G IPTV 기술이슈 - Service Quality 보장 - 기존서비스대체이외서비스능력제한 표준화관련이슈 - 비표준 CAS/DRM - 양방향서비스미들웨어 - Interoperability Issues Government regulatory issues on-scalable Architecture Major Telco, MSO 대규모가입자 ( 전화가입자의 50% 수준 ) Converged Network More than 기존 TV 표준플랫폼 (Middleware,CAS/DRM) MPEG4-AVC, SVC, WMV9 Codec? Global IPTV Exclusivity of Contents, Niche Contents Vision of Future IPTV Video on any IP device Future Telco Vedio Network Architecture - 보편적서비스 - Scalability - Global Interoperability Standard Platform Converged New Service 5 shyang@etri.re.kr
Definition of IPTV? (Telco..) ITU-T IPTV is defined as multimedia services such as television/video/audio/text/graphics/data delivered over IP based networks managed to provide the required level of QoS/QoE, security, interactivity and reliability (2006.7.) ATIS IPTV Exploratory Group(IEG) IPTV is defined as the secure and reliable delivery to subscribers of entertainment video and related services. These services may include, for example, Live TV, Video On Demand (VOD) and Interactive TV (itv). These services are delivered across an access agnostic, packet switched network that employs the IP protocol to transport the audio, video and control signals. In contrast to video over the public Internet, with IPTV deployments, network security and performance are tightly managed to ensure a superior entertainment experience, resulting in a compelling business environment for content providers, advertisers and customers alike. 6 # shyang@etri.re.kr
IPTV 응용서비스 source : IPTV Asia forum 2005, SIEMENS 7 # shyang@etri.re.kr
1G IPTV Architecture & Component IPTV Headend Contents, Codec, IP Streaming DRM/CAS, Middleware, Management Backbone Network Multicast Streaming + QoS Access Network Switched Channel + QoS per Subscriber Subscriber Premise IP-STB(Decoder, Middleware, IGMP) IRD IRD Encoder Encoder Streaming Server Billing Subscriber Management EPG Middleware Business Local Server IP Adaptor CAS/DRM Main Headend LAN xdsl FES FTTH DSLAM OLT L3/L2 Edge L3/L2 Edge L3/L2 Edge L2/L3 Multicast Routing: PIM-SM)/IGMP MM Streaming: UDP/RTP QoS: MPLS+DiffServ Residential -Access -Edge (Aggregation/ Distribution) Core (IP/MPLS) IP-STB/IPTV 8 # shyang@etri.re.kr
서비스망예 : PCCW Closed IPTV Delivery 네트워크 4.5MPEG 1.5Internet source : IPTV Asia forum 2005 source : IPTV Asia forum 9 # shyang@etri.re.kr
IPTV 서비스시스템예 10 # shyang@etri.re.kr
IPTV 서비스네트워킹기술현황 (1) 1G IPTV 기술 Future IPTV Delivery Architecture Access QoS Transport Control Protocol for Video Delivery and Serviec Service Control Home Networking Overlay 구조혹은 VPN Centralized Server xdsl, ADSL 위주 Ethernet 망분리 Over-provisioning + DiffServ MPLS + L2/L3 CoS IP/UDP/RTP/MPEG-2TS Unicast, 제한적 Multicast Contents Delivery Control for Core PIM-SSM for multicasting Multicast Group Management IGMPv3(RFC-3376) vs. IGMPv2 On-demand Service Control Real Time Streaming Protocol(RFC-2326) Client-Server Architecture 공통 Infra None IPTV Converged Network Video Switch(Router) Distributed Server(SPE, VHO, VSO) FTTH, Ethernet HFC, WiBro, WLAN MPLS + Service-driven RM + L2/L3 CoS Scalable Video Coding QoE and Performance Monitoring 효율성개선필요 IP/UDP/RTP/MPEG-2TS(DVB 방식 ) Direct IP Transport: ISMA?(MPEG-2TS 배제 ) Multicast 위주 Unified Signalling(SIP 기반?) IETF <-> SIP translation Scalable protocol 필요 (ex: RTSP) Service Control Architecture for Managed/Blended Service IMS integration? DLNA(UPnP) 11 # shyang@etri.re.kr
IPTV 서비스기술현황 (2) 1G IPTV 기술 Future IPTV 서비스 기존방송대체 서비스차별화 ( 콘텐츠, 개인화 / 양방향성등 ) 콘텐츠 기존방송콘텐츠, VoD 차별화되는채널 ( 스포츠같은 ) Niche Contents Prosumer Contents Targeted Contents 단말 Middleware Software Security Software Media Codec IP-STB+TV Hardware 기술? 비표준 ACAP, OCAP, MHP, 표준규격없음 CAS 규격위주 MPEG-2TS(SD, HD) H.264 IP-STB+TV, PC 형단말, 휴대용 Video/Audio Device, 휴대폰등 Remote Management IPTV 표준미들웨어? 다양한단말유형지원 IPTV 표준규격 OMA/ATIS/ITU-T? CAS + DRM H.264 H.264-SVC/ WMV 9.0? Channel Access Scheme Metadata (DVB: Service Discovery and Selection) 비표준 EPG (format/presentation/accessing) 표준기반 EPG/ 개인화 EPG 12 # shyang@etri.re.kr
FG-IPTV 의 Architecture 표준화현황 Globally Interoperable IPTV IPTV 관련표준연구결과들을통합 조정 추가적으로필요한규격에대한연구를촉진 IPTV Service Requirements 2007.5. Framework IPTV Architecture Service and Architecture QoS and Performance Security Network Control/Multicast End Terminal and Interoperability Middleware, Applications Reference Model High Level/Mid-Level/Use Case Global Interoperability 를위한 IF 및 FE Define 5개기술분야 G.I. SG13, NGN-GSI GSI SG9, SG15, SG16, ITU-R R WP6M, SG17 IPTV Architecture Gap Analysis & 새로운표준 FG- IPTV JCA-HN 13 shyang@etri.re.kr
ATIS 의연구현황 엔터테인먼트비디오및이와관련된서비스를안전하고신뢰성있게가입자에게전달 규격간조정, 장애이슈들의해결, 서비스및망간연동의활성화 Framework/Architecture IPTV Architecture Requirements(06.6.) 3 단계로드맵 IPTV Architecture Roadmap Phase Phase 1 Phase Phase 2 Phase Phase 3 기본서비스에대한기본 Spec. 트랜잭션기반서비스에대한규격 네트워크및서비스에대한기본접속 VoD, PPV 서비스의발견및네비게이션 양방향 TV, 멀티플레이어게임 네트워크기반의 PVR 댁내환경및 P2P 응용 1 단계 Architecture Reference Model Service/DRM/QoS(QoE)/System 규격규격연구 14 shyang@etri.re.kr
ATIS 의표준현황 (2) Framework/Architecture Service IPTV Architecture Requirements (2006.6.) IPTV Architecture Roadmap (2006.9.) Phase 1 Architecture Reference Model IPTV Multicast Network Service Specification Emergency Alert Service(EAS) Provisioning Spec. for IPTV IPTV Linear Broadcast Service DRM DRM QoS/QoE IPTV DRM Interoperability Requirements (2006.6.) IPTV DRM Interoperability Specification IPTV DRM Requirements for Distributing Content in the Subscriber s Authorized Service Domain Framework for QoS Metrics and Measurements Supporting IPTV Services(2006.12.) Packet Loss Issue Report(2007.1.) IPTV QoE-Model Requirements and Model Definition QoS Metrics for Linear Broadcast IPTV IPTV IPTV System IPTV High Level Architecture Service Provider/Network Provider Interface for IPTV Specification IPTV Terminal Function(ITF) Attachment and initialization Specificati Remote Management of Devices in the Consumer Domain 15 # shyang@etri.re.kr
Contents 1. IPTV 기술현황? 2. Architecture & Challenging technologies 3. 진화전망 4. Discussion shyang@etri.re.kr
IPTV Service Architecture? IPTV Service Architecture 단말 (X, Y, Z) 콘텐츠 (A, B, C) Srv Platform (D, E, F) Service Platform 표준관점 기술관점 Based on Role Model - 4 개주요사업자간 (CP, SP, NP, CE) - IW 을위한 Reference Model 정의 - IF, Function allocation Based on Service Architecture - Component 간의 IW 을위한 Reference 정의 - FE, IF, 시그널링 Spec 정의 Right infrastructure for differentiated IPTV? - Network based Service Control IMS 기반의공통서비스플랫폼 - Core IMS itself? Killer application of IMS? 17 shyang@etri.re.kr
Client-Server Model 상호운용성취약 비표준플랫폼 : 다양한 Client Headend 망은서비스세션인식못함 (Unmanaged Service) Customized QoS 제공제한 융합 / 부가서비스제한 망사업자수익모델취약 Service-dependent architecture CapEx/Opex 증가 Current IPTV Service Architecture Blending(users, devices, sessions) 제한 조기서비스도입에유리 Middleware+IGMP OK Decoder+B uffer IRD IRD Encoder Encoder Media Server IP Adaptor Billing Subscriber Management EPG Middleware CAS/DRM Delivery Network Main Headend 18 shyang@etri.re.kr
Right Infrastructure for IPTV? Network based Service Architecture Managed QoS and Security Infra Platform for Service Blending Advanced Service. Mobile IPTV, 개인화 TV Heterogeneous Service Environment( 단말, Access, Contents, Preference ) Efficient Delivery Control Unified Signalling CapEx/OpEx 절감 Scalability, Performance, Compatibility Middleware+IGMP OK Decoder+ Buffer Network based control Delivery Network IRD IRD Billing Subscriber Encoder Encoder Management EPG Media Server IP Adaptor Middleware CAS/DRM Main Headend 19 shyang@etri.re.kr
IMS as a common service control platform (for FMC) Src: 3GPP 20 shyang@etri.re.kr
IPTV based on IMS? Session control Common network rsc control for QoS and Access Control Authentication Subscriber database Service inter-working Location management Metering and Charging IF Contents Discovery and Selection Contents Packaging QoS Adaptability for mobile IPTV Adaptability for anywhere, any time, any IP device Src: IMS enabled IPTV, Wipro technologies 21 shyang@etri.re.kr
Integration of IPTV and IMS? Hmm. Let s talk about it. IMS 가있잖어 ~ IMS 에통합해서갑시다 ~ 가볍게갑시다!... (IBM, Nortel, Alcatel?) (SBC, Verizon?) Market (global, converging) Policy (local, silo) IMS? - Technical/Conceptual Value 확인 - Test Network 적용 Okay - Commercial Value? IPTV? Killer application of IMS? 서비스차별화 - Service blending, advanced service Heterogeneous Service Environment( 단말, Access, Contents, Preference ) Mobility Service 공통플랫폼 => CapEx/OpEx IMS 가답? Benefit? 22 shyang@etri.re.kr
Managed IPTV Service Infra Architecture Enhanced Service Feature Simple, Seamless, Secure, Personal, Auto-configurable Managed/Controlled Service Architecture 지향 Subscriber Data Signalling and Service Control Quality of Service and Resource management Accounting and Usuage Provisioning and Configuration Service-independent Architecture Session-based and Non-session-based application Blended Relationships btw Com-Objects for integrated service users, endpoint devices, and service sessions and contents Support a wide variety of UE devices Automated Contents/Service Searching and Selection Ad Insertion/Deletion Long-tail contents Optimal Contents/ 서비스 Broker 23 shyang@etri.re.kr
3 가지구조 FG-IPTV Architecture Overview NGN-based and IMS-based IMS 를도입하여 SIP 응용서비스제공중인사업자가 IPTV 서비스까지 IMS 기반으로. NGN-based and non-ims-based Managed Infra 를갖추고있으며, IMS 를도입하였거나, 혹은그렇지않은상태에서 IPTV 서비스를. IMS 이외의별도의 IPTV Control 을이용 Non-NGN-based Legacy 네트워크 (Best-effort IP Network) Service Control IMS-based Non-IMS IMS-based Transport/Network Control NGN-based (Managed QoS and Security) Non-NGN NGN-based 24 shyang@etri.re.kr
NGN-based Architecture? Y.2012 의 NGN FE 에준하여 25 shyang@etri.re.kr
Content location Content Distribution Content Delivery 구조 1: Non-NGN based 콘텐츠선택, 구매, 콘텐츠보호등 콘텐츠소스로부터다말까지의미디어전달 망 / 시스템자원의설정및유지제어 to support the delivery of the media streams - 사용자멀티미디어세션제어 - Session Level QoS Control - 서비스사용 Security 제어 - Media Delivery Control - IPTV 서비스상태정보수집및관리 ( 사용자, 단말, 콘텐츠등 ) - Service Usage 정보수집 - 콘텐츠소스로부터단말까지의미디어전달을위한 시스템 / 망자원의제어 / 관리 Media Stream e2e connectivity btw FE Session Mng & control Session Mng & control Using IMS Session Mng & control Using non-ims 26 shyang@etri.re.kr
구조 2: NGN based + non-ims/ims Session Control Non-IMS Session Control IMS Session Control 27 shyang@etri.re.kr
구조 3: NGN based + Coexistent non-ims and IMS Session Control IPTV Control GW? 28 shyang@etri.re.kr
2 서비스예 : IMS based VoD 3 8 6 1. GW, IP 할당및 Configure 2. IP단말 Configure 3. IPTV 응용 run, URL of Content 4.5.6. URL => 실제서버결정 7. Client Network 서버간연및자원할당 8. Contents to Client 5 4 7 1 29 shyang@etri.re.kr
2 3 8 서비스예 :IMS based Multicast TV 6 1. GW, IP 할당및 Configure 2. IP단말 Configure 3. IPTV 응용 run, 채널결정 4.5.6. 채널 => Multicast Addr 결정 7. Client Network 서버간연및자원할당 8. IGMP Join & Media 수신 5 4 7 1 30 shyang@etri.re.kr
Architecture Implementation Option(1) 1) Non-NGN 구조 ( 예 : AR 확장 ) IPTV Application Platform 4) IMS 세션제어 + IPTV GW Service Platform Call/Session Control HSS SIP IMS- Interworking IMS x Access IGMP/RTSP STB Status Report TV Core IPTV Control 세션기반응용 IPTV 응용. NACF X RACF X Access IGMP/RTSP STB TV Core 세션기반응용 방송형서비스. 31 shyang@etri.re.kr
Architecture Implementation Option(2) 3) IMS 통합구조 2) IMS + IPTV Control Service Platform( 기존 SIP 응용, IPTV 응용, Blended Service) 기존 SIP Applications/Contents IPTV Applications/Contents SIP/SIP x Call/Session Control HSS Call/Session Control HSS IPTV Control IPTV User Profile IMS x IMS x NACF RACF NACF X RACF X Access Core BCS Access BCS Core SIP x STB TV SIP 세션기반응용 IPTV 서비스. 세션기반응용 방송형서비스. STB 32 shyang@etri.re.kr TV
Service Architecture 비교분석 (1) 1) Non-NGN ( 예 :AR 기능확장 ) ( 주요특성 ) 2) non-ims Session Control 3) IMS Session Control 4) IMS Session + IPTV Control GW IPTV 세션제어 Authentication & Authorization QoS 자원관리 가입자관리 멀티캐스팅제어등 IPTV Control 의주요지원기능 IPTV 세션제어 Authentication & Authorization QoS 자원관리 가입자관리 멀티캐스팅제어등 IPTV 세션제어 Authentication & Authorization QoS 자원관리 가입자관리 멀티캐스팅제어등 IMS: 세션제어, 자원관리등 IPTV Control GW 기능 전달망 QoS 제어능력 Secure 서비스접속제어능력 확장성 (Scalability) 서비스계층 QoS 능력주 1) CapEx/OpEx 융합서비스제공능력 주1) 예로서33Response Time, Channel Zapping Time shyang@etri.re.kr 등
Service Architecture 비교분석 (1) 1) Non-NGN ( 예 :AR 기능확장 ) ( 주요특성 ) 2) non-ims Session Control 3) IMS Session Control 4) IMS Session + IPTV Control GW 호환성 (Compatibility) 구현복잡성 (Complexity) 다채널방송에적합 구축비용이가장큼 주요장단점 Secure & 고품질다채널방송 /VoD 구축 / 운용비용절감가능 가입자 DB 이원화 Mobile IPTV 제공한계 통합제어구조지향 구축 / 운용비용가장저렴 구격미비 IMS 진화필요 기술 Immature 통합제어구조지향 구격미비 IMS 진화필요 GW 시스템필요 액세스망 re-novation 사업자? 독립서비스사업자 사업자망적용및진화검토 TPS 지향사업자 NGN + IMS 인프라구축된 ( 중 ) 사업자 단계별로 IMS 통합구조로진화 TPS 지향사업자 IMS 도입을 3~4 년후로계획하는사업자 TPS 지향사업자 IMS 도입된 ( 중 ) 인사업자 34 shyang@etri.re.kr
Technical Issues in IPTV Service Architecture? IPTV Session e2e relationship btw a pair of FC through out its duration IPTV Session IPTV Application related: ex. IPG Delivery of the Content related 3 approaches Non-IMS(IPTV Control) IMS for Application and Content Sessions IMS for Content Sessions IMS + IPTV Integration Real benefit?... Mobile IPTV, Customized TV Service blending IMS에끼워맞추는것이아니라. Advanced IMS를 Middleware IMS interworking Signalling for Service Control Media Delivery Control SIP Unified Signalling Feasible and effective? Architecture evolution path? 35 shyang@etri.re.kr
Challenging : Mobile IPTV? Seamless and Optimized Service Delivery in Heterogeneous Service Environment IMS(Database + Control) + QoS Monitoring + SVC Media-aware IP delivering for optimization Harmonization of ( 단말능력, 소스특성, 유무선전달망의동적 QoS 특성 ) H.264-SVC Status/Capability 수집 Feedback for frame filtering control Signalling + SVC Frame filtering architecture Heterogeneous Terminal IMS NG Rich Profile & Status Heterogeneous Level Contents 1. 단말능력 3. 소스 QoS 특성 2. 망 QoS 능력 (Dynamic) SVC Control Heterogeneous FM Converged Network (Dynamic Status) 36 shyang@etri.re.kr
Contents 1. IPTV 기술현황? 2. Architecture & Challenging technologies 3. 진화전망 4. Discussion shyang@etri.re.kr
IPTV 서비스진화전망가입자수증가<1 단계 > - 기술적타당성확인 - 기본서비스의신속한제공 - 현존방송및통신기술결합 - Managed 네트워크기반의기본서비스요소에대한표준플랫폼구축 <2 단계 > - 서비스차별화, 보편적서비스 - 양방향, QoS/QoE, 홈네트워크 - 네트워크기반서비스제어인프라 - 서비스차별화 - 보편적서비스로확산 - 홈네트워크 + QoS - 네트워크기반의서비스 / 네트워크제어 - 이동성, 융합서비스 - 품질, 보안이보장되는글로벌연동 - 이동성, 융합서비스 - 품질과보안이보장되는글로벌연동 - IMS 통합 <3 단계 > 서비스 Basic Linear Broadcast MMoD Interactive and Trick mode Plentiful Contents (UCC, 3 rd Party) Mobility, Service Blending Global Interoperability 38 shyang@etri.re.kr
Evolution of IPTV Service and Network Phase 1 (1G IPTV) Phase 2 (2G IPTV) Phase 3 (3G IPTV) 목표 방송형기본서비스네트워크통합 Bundled Service Basic Service Offerings Integrated Services 개인화, Interactivity Managed/Controlled Service Architecture Quality of Experience 이동연속형서비스 Scalability Interoperability Middleware for heterogeneous service environment 서비스특성 Contents 다채널방송 ( < 수십채널 ) VoD 서비스 Service feature Time-shift TV Basic EPG PVR/NPVR Contents 다채널방송 ( < 수백채널 ) VoD Narrowcasting User Created Contents Service feature Personalized Channel/EPG 소통가능 TV(CommunityTV) 양방향성 (Contents control) Contents 다채널방송 ( < 수백채널 ) VoD More Narrowcasting More User Created Contents long tail Contents Service feature Mobile TV Blended Service Customized 콘텐츠검색및접속 Customized Ad 비즈니스모델 Bundled Service: ARPU 개선 제한된주거가입자 ( < 5%) 정액제위주 고품질, 가입자제어형서비스창출 가입자확산 ( 30%) 정액제, Pay Channel, 광고수익등수익모델다양화 서비스차별화 / 다양화 Global Interoperable Service 안정화단계 (50%) 다양한요금제 39 # shyang@etri.re.kr
Evolution of IPTV Service and Network - 계속 Phase 1 Phase 2 Phase 3 가입자환경 TV + STB 형단말 TV + STB 형단말 PC 형단말 Home Network TV + STB 형단말 PC 형단말 Home Network Mobile phone 형 Portable Video Devices Network Infra Overlay MPLS(RSVP) + DiffServ SLA 기반 Static RM 제한적 Multicast(PIM, SSM, IGMP) 광대역유선액세스 (xdsl, PON, Ethernet) Converged MPLS(RSVP) + Managed Access Service-driven RM and TM Storage networking 광대역유선액세스 (xdsl, PON, Ethernet, HFC) MPLS(RSVP) + Multicasting + Dynamic Access Wireless(WLAN, WiBro, PAN) Service Infra Server-Client 구조 Service Control Architecture for Session-based service(ex:voip) Managed IPTV Service Control Architecture Subscriber, Service Access QoS Session Network accounting and Usuage Configuration and Management Service Presence Unified MM Service Control Architecture(IMS 구조통합 ) Signalling and Service Control Customized Service/Contents Broker Blended Service Control Auto-configurable Service environment Mobility Control 40 # shyang@etri.re.kr
Evolution path for IPTV Service Architecture? IMS-app For wireless IMS-app For wireless IMS-app For BB wireline IMS-app For wireless IMS-app For BB wireline IMS-app For MSOs IMS IMS-N2 IMS-N3 IPTV app For wireline for converged terminal(ims and non-ims) for wireless/mobility for QoS control for Blended service IPTV app For wireline for wireless/mobility for converged terminal (IMS and n Client-Server for QoS control for Blended service IPTV Control Web app For wireline Client-Server? 41 shyang@etri.re.kr
Discussion: Challenges for IPTV 2G and IPTV 3G Future Video Networking Infrastructure Scalable and efficient video networking Harmonization bwt MPEG vs. IP delivery Applying Scalable Video Coding Scalable and QoS guaranteed Multicasting QoS/QoE Control and Monitoring Future Converged Service Control Infrastructure Converged Terminal and Converged Service IMS 연동 vs IMS 통합 융합서비스? 가입자프로파일공통으로? RACF/NACF Control 공통으로? 단계별 IMS 통합 가입자 / 서비스정보 NACF, RACF 호 / 세션 Control Unified Service Signalling Session level signalling protocol: SIP vs. RTSP? Harmonization of Session level control Streaming Control Human Interface Technology for Interactive IPTV. 42 shyang@etri.re.kr