IP Multimedia Subsystem(IMS) and Its Applications

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KNOM Conference April 26 ~ 27 2007 IP Multimedia

1 KNOM Conference April 26 ~ IP Multimedia Subsystem(IMS) and Its Applications Jun-Won Lee 1

2 Contents IMS Overview IMS Architecture Contents IMS Applications IMS Enablers & Clients 2

IMS Overview IP Multimedia Subsystem (IMS) An architectural framework for delivering IP multimedia services to end users, originally designed by 3GPP At the heart of Next Generation

3 IMS Overview IP Multimedia Subsystem (IMS) An architectural framework for delivering IP multimedia services to end users, originally designed by 3GPP At the heart of Next Generation Convergent Networks Pre-IMS Pre-IMS Communications Communications (Service (Service Islands) Islands) IMS IMS Communications Communications (Integrated (Integrated Services) Services) 3

4 IMS Overview Network Convergence Services Services IMS Location/Auth HSS Connectivity Core Access FIXED MOBILE xdsl WiMAX WLAN GERAN WCDMA User 4

5 IMS Overview - What IMS Provides Services and Control Adds call session control to the packet network Enables peer-to-peer real-time services - such as voice, video - over a packet-switched domain Mixed Multimedia Ability to pick and mix various multimedia flows in single or multiple sessions Can handle real-time voice, video, data Connectivity Independence Provides access to IP based services independent of the connectivity network: mobile (3GPP s UMTS, 3GPP2 s CDMA2000) and fixed networks (TISPAN s NGN) 5

IMS Overview - Standards 3GPP has developed IMS for delivering

support of CDMA2000 TISPAN is defining the NGN network based on 3GPP

services based on the 3GPP IMS service platform IETF standards such

Internet 3GPP : 3 rd Generation Partnership Project TISPAN : Telecom

6 IMS Overview - Standards 3GPP has developed IMS for delivering Internet Services over GPRS 3GPP2 is defining requirements for support of CDMA2000 TISPAN is defining the NGN network based on 3GPP IMS and adapting 3GPP IMS to fixed access networks OMA is defining services based on the 3GPP IMS service platform IETF standards such as SIP is fully utilized for IMS to ease the integration with the Internet 3GPP : 3 rd Generation Partnership Project TISPAN : Telecom & Internet converged Services & Protocols for Advanced A Network OMA : Open Mobile Alliance 6

7 IMS Overview SIP centerred 7

8 Contents IMS Overview IMS Architecture Contents IMS Applications IMS Enablers & Clients 8

9 IMS Architecture - Overall 9

10 IMS Architecture - Simplified 10

11 IMS Architecture Major Components HSS (Home Subscriber Server) UPSF (User Profile Server Function) Master user database Subscription-related information (user profiles) Performs authentication and authorization Provides information about the physical location of user SLF (Subscriber Location Function) Map user addresses when multiple HSSs are used 11

12 IMS Architecture Major Components Note Note User Identities IMSI (International Mobile Subscriber Identity) : a unique user identity that is stored in the SIM TMSI (Temporary Mobile Subscriber Identity) : To improve privacy, a TMSI is generated per geographical location. IMSI/TMSI are used for user identification. IMEI (International Mobile Equipment Identity) : a unique device identity MSISDN (Mobile Subscriber ISDN Number) : telephone number of a user Additional Identities with IMS IMPI (IP Multimedia Private Identity) : a tel-uri or sip-uri. Unique to the phone. More than one IMPU per IMPI IMPU (IP Multimedia Public Identity) : a tel-uri or sip-uri. IMPU can be shared with another phone. Both the phone can be reached with the same identity 12

13 IMS Architecture Major Components P-CSCF (Proxy Call Session Control Function) First point of contact for the IMS client Assigned to an IMS terminal during registration, and does not change for the duration of the registration Sits on the path of all signalling messages, and can inspect every message Authenticates the user and establishes an IPsec security association with the IMS terminal. This prevents spoofing attacks and replay attacks and protects the privacy of the user. Other nodes trust the P-CSCF, and do not have to authenticate the user again. Compress and decompress SIP messages using SigComp, which reduces the round-trip over slow radio links May include a PDF (Policy Decision Function), which authorizes media plane resources e.g. quality of service (QoS) over the media plane. It's used for policy control, bandwidth management, etc... The PDF can also be a separate function. Generates charging records 13

14 IMS Architecture Major Components S-CSCF (Serving CSCF) Central node of the signaling plane Uses DIAMETER to talk with HSS to download and upload user profiles. No local storage for the user Handles SIP registration thus binding the user location(ip addr) and the SIP address Decides to which application servers the SIP message will be forwarded Routing service using ENUM lookups Multiple S-CSCF for load distribution and high availability reasons 14

15 IMS Architecture Major Components I-CSCF (Interrogating CSCF) At the edge of an administrative domain A forwarding point for SIP packets to other domain THIG (topology hiding inter-network gateway) function From Rel7, this function is transferred to a new entity, IBCF(Interconnection Border Control Function) 15

16 IMS Architecture Major Components Application Servers Host and execute services Interfaces with the S-CSCF (ISC interface) Example services Caller ID, Call waiting, Call forwarding, Call transfer, Call hold, Call pickup Conference call Voice mail, Unified Messaging Text-to-speech, Speech-to-text Push-to-talk (PTT) Location based services Presence, Instant Messaging Voice Call Continuity (VCC) Etc. Types SIP AS : native IMS application server OSA-SCS(Open Service Access Service Capability Server) : interface with OSA application servers using Parlay IM-SSF(IP Multimedia Service Switching Function) : interface with CAMEL application servers using CAP 16

17 IMS Architecture Major Components MRF (Media Resource Function) Used for Playing of announcement (audio/video) Multimedia conferencing Text-to-speech and speech recognition Real-time transcoding of multimedia data MRFC (Media Resource Function Controller) Signaling plane node Controls MRFP with a H.248 interface MRFP (Media Resource Function Processor) Media plane node 17

18 IMS Architecture Major Components BGCF (Breakout Gateway Control Function) Routing functionality based on telephone numbers SGW (Signaling Gateway) Transforms lower layer protocols (SCTP into MTP) Pass ISUP from MGCF to the CS network MGCF (Media Gateway Controller Function) Protocol conversion between SIP and ISUP Interfaces with SGW over SCTP Controls resources in an MGW with a H.248 MGW (Media Gateway) Converting between RTP and PCM Transcoding 18

19 IMS Architecture REGISTER Flows 19

20 IMS Architecture Session Setup Flows (1) 20

21 IMS Architecture Session Setup Flows (2) 21

22 IMS Architecture Session Setup Flows (3) RTP 22

23 Contents IMS Overview IMS Architecture Contents IMS Applications IMS Enablers & Clients 23

communications while one person speaks, the other(s) listen Immediate and

24 IMS Applications - PoC PoC (Push-to-Talk over Cellular) a walkie-talkie type service that provided over a cellular phone network half duplex communications while one person speaks, the other(s) listen Immediate and instant communication Video and text as well as voice Open standard-based (OMA) 24

IMS Applications - Video Sharing Video Sharing Sharing one-way live video or video clips in real time during a normal voice call Enhances a voice call with the ability

25 IMS Applications - Video Sharing Video Sharing Sharing one-way live video or video clips in real time during a normal voice call Enhances a voice call with the ability to share video among users New opportunity for mobile operators to gain additional revenue from voice calls Prolonged voice call duration Open standard based (GSMA) 25

26 IMS Applications Video Sharing (From Nokia s s WP) 26

27 IMS Applications VCC (Voice Call Continuity) 1) Basic Concept of VCC Anchoring and Switching at VCC AS VCC AS IMS Core WiBro 1x OEP Wi-Fi Access IP Core Network MGCF MGW OEP (other end point) Handover Dual-Band Handset Device CDMA 1x MSC 27

IMS Applications VCC (Voice Call Continuity) 2) Signal Flow for VoIP to CDMA Hand-Over OTHER END POINT PS [3 ] [4] [7 ] Call Flows [1] Call Origination MGCF + MGW [2] [5] [3] [4

28 IMS Applications VCC (Voice Call Continuity) 2) Signal Flow for VoIP to CDMA Hand-Over OTHER END POINT PS [3 ] [4] [7 ] Call Flows [1] Call Origination MGCF + MGW [2] [5] [3] [4 ] [7] IMS Core + VCC AS [2] ISUP:IAM [3] SIP:INVITE [4] SIP:200 OK [5] ISUP:ANM [6] 1x TCH Setup [8] [9] [7] SIP:ACK CS MSC/VLR [1] [6] [8] SIP:BYE [9] SIP:200 OK {ckt} {pkt} UE 28

29 Contents IMS Overview IMS Architecture Contents IMS Applications IMS Enablers & Clients 29

30 Overall IMS Architecture IMS Clients Portable to Any Device Presence IMS Enablers (or Application Servers) IM VCC PoC Video Share HSDPA MRFC S-CSCF BGCF CDMA MRFP MRF I-CSCF P-CSCF HSS SLF MGC MGCF SGW WiBro IMS Core MGW WiFi Managed IP Network PSTN/PLMN xdsl 30

31 OMA Perspectives Trend of Mobile Phone: Convergence of Data Service Four Categories of Data Service, >> Communication, Entertainment, Information, and Finance Messaging SMS,MMS Voice IM Push2X(show/video) Communication Entertainment M-game Broadcast, Music Avatar, Ringtone PIMS Personalized Contents LBS Telematics Information Finance Payment Purchasing M-banking Trading 31

32 OMA Enabler Roadmap 32

33 OMA Reference Model DMS DM-1 DMC XDM Client XDM-3 Shared XDMS XDM-4 PRS-9 PRS-5 Aggregation Proxy PRS-7 Presence XDMS PRS-8 Presence Server PRS-12 RLS XDMS PRS-10 Resource List Server PRS-15 PRS-11 PRS-6 PRS-4 PRS-3 XDM-2 Content Server SIP / IP Core PRS-1 PRS-2 PRS-13 Presence Source PRS-14 Watcher Remote Presence Network (based on SIP/IP Core) XDM-1 IP-1 33

34 IMS Client Overview IMS Client can be layered into 3 main parts among which IMSCF(IMS Client Framework) is the most important part to be an IMS-compliant client. Active Phone book VoIP PTA (Push-to-All) Instant Messenger IMS enabled Game Video Conference Application Part GSMA Video Sharing OMA PoC SDP MSRP Media Processing SIP/SIMPLE Digest AKA RTP/RTCP XCAP SigComp IMS Client Framework SW AV Codec DSP Chip Windows Mobile 5.0 Qualcomm REX/DMSS WIPI BREW Symbian Device Specific Part 34

35 IMS Client Overview Technologies Various Protocols Support SIP/SDP/RTP/RTCP/MSRP/XML/XCAP/ Various Standard Organizations 3GPP, OMA, IETF, Various Media Support Voice, Video, Music, Images, etc. Wide range of Platform Support (Portability) Any device Key requirement for IMS client platform End-user applications Attractive and Intuitive GUI Easy to use 35

36 IMS Client Framework Nable IMS Client Architecture 3 rd Pty Appls 3 rd Pty Appls VCC Client Video Sharing Application Video Telephony Instant Messenger Instant Messenger IMS Core Adaptation for Windows Window Mgt Local Data Mgt Applications Windows OS Adaptation (Option) High Level APIs for IMS Applications 3 rd Pty Enablers 3 rd Pty Enablers VCC Video Sharing VoIP/ Conf IM/ Presence PoC Generic Session Mgt. Generic Event Mgt. IMS Framework Other APIs TAPI etc. Media API IMS Core API Other Devices & Features WiBro /Wi-Fi CDMA /GSM SPIRIT, GIPS, Etc. Media Filter RTP/ RTCP SIP/SIMPLE w/ sigcomp MSRP Platform Adaptation Layer XCAP A/V Codec, Device Memory, Network, File I/O, Event Any Device and Platform (Qualcomm REX/DMSS, Windows Mobile, Symbian, etc.) Platform & APIs 36

37 Contact : Jun-Won Lee, jlee@nablecomm.com,,

8.4 IMS Network Architecture A Closer Look

8.4 IMS Network Architecture A Closer Look 243 The anchoring of the media in TrGW also has an implicit topology-hiding effect. Without anchoring, the SDP answer provided to the other network would contain