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Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2006 Telcordia Technologies.

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Presentation on theme: "Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2006 Telcordia Technologies."— Presentation transcript:

1 Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2005 Telcordia Technologies All Rights Reserved Copyright © 2006 Telcordia Technologies All Rights Reserved IP Multimedia Subsystem (IMS): Concepts and Architecture Contact: Zehan Zeb (732) Contribution to: NANC FoN October 4, 2006

2 2 IMS Concepts and Architecture Outline IMS Concepts – Introductory concepts and IMS general terminology Functional Entities and their Roles – Major nodes/entities – Roles and functions provided – Architecture associated with major functional entities Overall Architecture Summary

3 3 IMS Concepts How Did We Arrive At IMS? Definition of IMS UE User Identities IP Connectivity Access Network (IP-CAN) IP Multimedia Sessions Transition to IMS Architecture

4 4 How did we arrive at IMS? Technology Evolution PSTN Circuit switched Analog Digital SS7 ISDN Circuit switched Analog Digital 2G (GSM & CDMA ANSI-41) 3G Wireless Wireless 3G wireless + IP ++ – Standard Services Platform – Converged Applications & Content – Access Independence IP IMS Internet – VoIP – Instant Messaging – Web Applications W-CDMA GPRS/UMTS

5 5 IMS Concepts What is IMS? IP Multimedia Subsystem (IMS) is a Service Delivery Architecture Standardized architecture to provide Internet Protocol (IP)-based mobile and fixed multimedia services IMS architecture has evolved over the past few years Today, IMS could allow operators who own different types of networks with varying architectures to offer the same services to all of their customers

6 6 IMS Concepts User Equipment (UE) UE: A device that has IP connectivity and is able to request an IP address from the network – Examples: SIP phone, PC, PDA UE negotiates its QoS requirements and other capabilities during a session setup UE negotiates items, such as: – Media Type – Direction of traffic – Bit rate, packet size, bandwidth adaptation

7 7 IMS Concepts IMS User Identification An IMS user is allocated one or more Public User Identities by the home operator A Public User Identity is either a SIP URI or a TEL URL – When the Public User Identity contains a SIP URI, it typically takes the form of – When the Public User Identity contains a TEL URL representing a phone number in international format it typically takes the form of tel: – It is possible to include a telephone number in a SIP URI using the following format: – TEL URLs are needed for inter-working with PSTN phones In IMS, Public User Identities are used to route SIP signaling

8 8 IMS Concepts IMS User Identification (contd.) Each IMS subscriber is assigned a Private User Identity by the home operator Unlike Public User Identities, Private User Identities are not SIP URIs or TEL URLs – They take the format of a NAI (Network Access Identifier) – The format of a NAI is Private User Identities are exclusively used for subscription identification and authentication purposes Private User Identities are not used for routing SIP requests

9 9 Relationship Between User Identities tel: Public User Identities Private User Identity IMS Subscriber

10 10 IMS Concepts 3GPP IP-CAN UE IP-CAN (GPRS -based) IMS Nodes SGSN GGSN RAN IMS network utilizes IP-CAN to transport multimedia signaling and bearer traffic It is the network that connects the UE to the IMS network

11 11 IMS Concepts IP Multimedia Session (contd.) UE1 IP-CAN IMS Media (data) Flow Session control signaling UE2 IP-CAN An IP Multimedia Session is comprised of session management control connections and media flow connections between two or more users IMS users are able to mix and match a variety of IP-based services in a way they choose during a single communication session

12 12 IMS Concepts- Transition Public Land Mobile Network (PLMN) SS7/ ISUP MSC SCP HLR Carrier A GSM / ANSI Network MSC HLR Carrier B GSM / ANSI Network SCP

13 13 IMS Concepts-Transition IMS Architecture: High Level View UE1 SIP IMS Network Carrier A IMS Network Carrier B ASs HSS ASs CSCFs UE2

14 14 IMS Concepts-Transition Interoperability: High Level View UE SIP IMS Network Carrier A IMS Network Carrier B ASs HSS Interworking Functions SSPSCP PSTN ISUP HSS ASs CSCFs ISPs UE

15 15 Functional Entities IMS Architecture Planes or Layers Various Functional Entities and their Roles

16 16 Functional Entities IMS Architecture Planes Application Server Session Control DB Centralized Databases Media Control & Gateways PSTN 2G/3G Mobile Wireless Broadband Wireline Broadband Res./ Enterprize Services plane (Application Layer) Session Control Plane (Session and DB Layer) Media Control Plane (Media Control & Gateway Layer) Network Plane (Access and Transport)

17 17 Functional Entities Network Plane: Access and Transport PSTN 2G Mobile/ PLMN Wireless Broadband/ 3G Wireline Broadband Res./ Enterprize Network Plane (Access and Transport) IP MSC EO/ SSP Circuit Switched Gateways Session Controllers SS7

18 18 Functional Entities Session Control Plane

19 19 Functional Entities Session Control Plane CSCF DB HSS CXCX

20 20 Functional Entities Session Control Plane: CSCF Call Session Control Function DB HSS P-CSCF I-CSCF S-CSCF UEs first point of contact Interrogating to load balance UE session management ISC Cx

21 21 Functional Entities Session Control Plane: P-CSCF Roles Proxy- CSCF UEs first point of contact Authenticates and asserts an identity to the UE Manages QoS, resource allocation, and controls charging function May contain a PDF which Manages resource allocation and QoS May reside in the visited or home network PDF

22 22 Functional Entities Session Control Plane: I-CSCF Roles Interrogating- CSCF Determines UE location by communicating with the HSS Finds the appropriate S-CSCF Performs load balancing Typically resides in the home network DB HSS

23 23 Functional Entities Session Control Plane: S-CSCF Roles Serving- CSCF Responsible for all session management activities Retrieves user profile and authentication information from the HSS Enforces the policy of the network operator Finds the appropriate AS Provides SIP routing Always resides in the home network DB HSS

24 24 Functional Entities Session Control Plane: HSS Home Subscriber Server (HSS) is the main data storage for all subscriber and service-related data of the IMS subscriber The HSS contains all the user-related subscription data required to handle multimedia sessions o All the data related to a particular user are stored in a single HSS The HSS is always located in the home network Although the functionalities are the same, 3GPP and 3GPP2 HSSs are described differently

25 25 Functional Entities Session Control Plane: HSS (3GPP) CSCF PDF Home Subscriber Server IMS Functionality HLR/AUC Function for PS HLR/AUC Function for CS Contains a user profile - bound to a Private User Identity and to the collection of Public User Identities The user profile contains a number of service profiles The service profile is divided into three parts: a collection of one or more public identifications an optional service authorization zero or more filter criteria

26 26 Relationship Between User Identities and Service Profiles tel: Service Profile1 Service Profile2 Public User Identities Private User Identity IMS Subscriber a user profile is bound to a Private User Identity and to the collection of Public User Identities user profile

27 27 Functional Entities Media Control Plane

28 28 Functional Entities Media Control Plane: MRF MRFC The MRF (Media Resource Function) deals with the media in the IMS network MRFC: The MRFC handles communication with the S-CSCF and controls the resources in the MRFP MRFP: The MRFP in the media plane implements all the media-related functions, such as playing media, providing announcements and mix media MRF resides in the home network. MRF MRFP Media Plane Signaling Plane

29 29 Inter-working Functions BGCF, SGW, MGCF, & MGW BGCF The MGCF receives SIP call control signal from the IMS network and performs conversion to ISUP/IP and sends to SGW. MGCF also controls MGW. The SGW performs signaling conversion in the transport layer and interfaces with PSTN in the control plane The MGW performs media conversion and interfaces with PSTN. The BGCF selects another BGCF OR an appropriate PSTN/CS gateway MGWMGCFSGW

30 30 Inter-working Functions BGCF, SGW, MGCF, & MGW (ctd.) BGCFMGCF SGW MGW Signaling (e.g., ISUP/MTP) Media (e.g., Voice bit stream) Switch SIP IMS Network PSTN Network

31 31 Functional Entities Services Plane: Applications Servers

32 32 Functional Entities Services Plane: Applications Servers SIP ASOSA-SCS IM-SSF S-CSCFHSS ISCSh Cx MRFC Mr

33 33 Overall IMS Architecture

34 34 IMS Architecture (3GPP View) UE IP-CAN (GPRS -based) SGSN GGSN RAN IM- MGW AS Ut P-CSCF Gm I-CSCF Mw Sh, Si HSSSLF Dh S-CSCF MRFC MRFP MGCF Mg Mn Mb CxDx Other IP/IMS Mw BGCF Mj Mk Mp Mb Mi SGWCS PDF Gq Go Mr ISC

35 35 Example: CNAM Call Flow Control Bearer Called Party Visited Network Calling Party Home Network Calling Party Visited Network UE1 P-CSCF HSS S-CSCF SIP Diameter UE2 P-CSCF AS HSS S-CSCF SIP IM-SSF SIP I-CSCF Diameter ENUM Backbone Packet Network RAN Backbone Packet Network RAN Initiate SIP Invite 1 1 Retrieve Subscriber Profile (if needed) Apply Service Logic Retrieve Address of CLD Party Home Network 4 4 Identify Registrar of CLD Party and Forward INVITE 5 6 Retrieve Subscriber Profile 6 7 Apply Service Logic to access IM-SSF AS Forward INVITE to CLD Party 9 9 SDP Negotiation / Resource Reservation Control RTP Stream Ringing / Alerting Answer / Connect RTP Stream 13 Session Active 7 8 IM-SSF queries a GSM-SCF if inter-working with PLMN needed Called Party Home Network 8 SCF 5 LIDB/ CNAM

36 36 Summary IMS Architecture: High Level View UE SIP IMS Network Carrier A IMS Network Carrier B ASs HSS Interworking Functions SSPSCP PSTN ISUP HSS ASs CSCFs

37 37 IMS Architecture Comments/Questions? Thank You!!

38 38 IMS White Paper Acronyms 3GThird Generation 3GPP3rd Generation Partnership Project 3GPP23rd Generation Partnership Project 2 AAAAuthentication, Authorization and Accounting AMFAccount Management Function ANIApplication-to-Network Interface ANSIAmerican National Standards Institute APIApplication Programming Interface ASApplication Server ASNAbstract Syntax Notation ATISAlliance for Telecommunications Industry Solutions ATMAsynchronous Transfer Mode ATPAcceptance Test Plan AUCAuthentication Center BGCFBreakout Gateway Control Function BTBritish Telecom CAMELCustomized Applications for Mobile Network Enhanced Logic CAPCAMEL Application Part CBFCharging and Billing Function CCFCharging Collection Function CDFCharging Data Function CDMACode Division Multiple Access

39 39 IMS White Paper Acronyms CDRCharging Data Records CGFCharging Gateway Function CLECCompetitive LEC CNCore Network COPS Common Open Policy Service CPECustomer Premises Equipment CSCircuit-switched CSCFCall Session Control Function CTIACellular Telecommunications and Internet Association DBDatabase DHLRDistributed Home Location Register DIAMETERAAA or HSS protocol; successor/upgrade of RADIUS DMSDual Mode Services DNSDomain Name System DSLDigital Subscriber Line E9-1-1Emergency Services ECFEvent Charging Function EDGEEnhanced Data Rates for GSM Evolution EIAElectronics Industry Association ENUMTelephone Number Mapping GGSNGateway GPRS Support Node GPRSGeneral Packet Radio Service GSAGlobal Mobile Suppliers Association GSMGlobal System for Mobile Communication HLRHome Location Register HSSHome Subscriber Server

40 40 IMS White Paper Acronyms HTTPHyperText Transfer Protocol I-CSCFInterrogating Call Session Control Function IETFInternet Engineering Task Force IMInstant Messaging IM-SSFIP Multimedia Services Switching Function IMSIP Multimedia Subsystem IMS-MGWIMS Media Gateway Function IMT-2000International Mobile Telecommunications 2000 INIntelligent Networks IPInternet Protocol IP-CANIP Connectivity Access Network IPDRInternet Protocol Detail Record IPsecIP Security IPv4IP Version 4 IPv6IP Version 6 ISCIMS Service Control ISDNIntegrated Services Digital Network ISGIntelligent Services Gateway ISOInternational Organization for Standards ISUPISDN User Part ITInformation Technology LANLocal Area Network LECLocal Exchange Carrier LNPLocal Number Portability MAPMobile Application Part MCSMultimedia Communications Server

41 41 IMS White Paper Acronyms MEGACOMedia Gateway Control (protocol) MGCFMedia Gateway Control Function MGFMedia Gateway Function MGIFMobile Gaming Interoperability Forum MGWMedia gateway MPLSMulti-Protocol Label Switching MRFMedia Resource Function MRFCMedia Resource Function Controller MRFPMedia Resource Function Processor MSFMultiservice Switching Forum MSO Multi-Service Operator MTPMessage Transfer Part NAINetwork Access Identifier NANPNorth American Numbering Plan NENetwork Element NGNNext Generation Network NNINetwork Node Interface OAM&POperations, Administration, Maintenance and Provisioning OCFOnline Charging Function OCSOnline Charging System OMAOpen Mobile Alliance OSAOpen Service Access OSIOpen Systems Interconnection OSSOperations Support System PCPolicy Controller P-CSCFProxy Call Session Control Function

42 42 IMS White Paper Acronyms PDAPersonal Digital Assistant PDFPolicy Decision Function PDSPacket Data Subsystem PDSNPacket Data Service Node POTSPlain Old Telephone Service PSTNPublic Switched Telephone Network PLMNPublic land Mobile Network QoSQuality of Service RANRadio Access Network RADIUSRemote Authentication Dial In User Service RFRating Function RTPReal-Time Transport Protocol RTCPRTP Control Protocol SBCSession Border Controller SCCPSignaling Connection Control Part SCFSession Charging Function SCIMService Capability Interaction Manager SCPService Control Point S-CSCFServing Call Session Control Function S-CSCFServing CSCF SCTPStream Control Transmission Protocol SCFService Control Function SCPService Control Point SCSService Capability Server SDOStandards Development Organization SDPSession Description Protocol

43 43 IMS White Paper Acronyms SGFSignaling Gateway Function SGSNServing GPRS Support Node SGWSignaling Gateway SIGTRANSignaling Transport SIPSession Initiation Protocol SLAService Level Agreement SLFSubscriber Locator Function SMSShort Message Service SNMPSimple Network Management Protocol SOAService Oriented Architecture SS7Signaling System 7 SSLSecure Sockets Layer SSFService Switching Function SSPService Switching Point TASTelephony Application Serer TBCP Talk Burst Control Protocol TCAPTransaction Capabilities Application Part TCPTransmission Control Protocol TDMTime Division Multiplexing TIATelecommunications Industry Association TSG-CTTSG Core Network and Terminals (3GPP) TSG-GERANTSG GSM EDGE Radio Access Network (3GPP) TSG-RANTSG Radio Access Network (3GPP) TSG-SATSG Service and System Aspects (3GPP) UDPUser Datagram Protocol

44 44 IMS White Paper Acronyms UEUser Equipment UMTSUniversal Mobile Telecommunications System UNIUser-to-Network Interface URIUniversal Resource Identifier URLUniform Resource Locator UTRAUniversal Terrestrial Radio Access UWBUltra-Wideband VCCVoice Call Continuity VoIPVoice over IP VPNVirtual Private Network VSPVirtual Service Provider WCITWorld Conference on International Telecommunications WINWireless Intelligent Network WGWorking Group WiFi802.11x wireless technology WiMAX802.16x wireless technology WINWireless Intelligent Network WLANWireless LAN WTSCWireless Technologies and Systems Committee (ATIS) xDSLVariations of DSL

45 45 IMS Architecture References 1. The 3G IP Multimedia Subsystem (IMS), Merging the Internet and the Cellular Worlds, by Gonzalo Camarillo and Miguel A. Garc´ıa-Mart´ın, IP Multimedia Concepts and Services by Mikka Poikselka, Georg Mayer, Hisham Khartabill, Aki Niemi, GPP TS : Technical Specifications Group Services and System Aspects; IP Multimedia Subsystems (IMS), Stage 2, 12/ GPP2 X.S A: All-IP Core Network Multimedia Domain, Overview, 11/ GPP2 X.S A: All-IP Core Network Multimedia Domain, IMS, Stage 2, 11/2005


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