IMS An Architecture for Convergent Next Generation Multimedia

IMS: An Architecture for Convergent Next Generation Multimedia Services. Research and Standardisation Challenges Dr. Sorin Georgescu sorin. georgescu@ericsson. com

Agenda § § § IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and Standardisation Challenges IMS Convergent Multimedia Services 2 Sorin Georgescu

Next Generation Networks Evolution Drivers Societal and Business trends Convergence • Internet is becoming a major enabler • Converged devices (Mobile, WLAN, of communications Internet etc. ) Connectivity • Consumers are embracing computing, mobile and digital technology in their everyday life • Converged services Ease of use • Converged networks Reliability, Security, Reduced OPEX/CAPEX • Evolution of Business models require increased levels of personal mobility • Converged business models Increased margins, Avoidance of twin pitfalls risk Access Technology Enhancements • HSPA (High Speed Packet Access) – evolved WCDMA • OFDMA (Orthogonal Frequency Division Multiple Access) – 3 GPP LTE, Wi. MAX, MBWA, ADSL/VDSL, DVB-T/H etc. • Spatial Processing – multi-antennas Base Stations supporting advanced spatial processing IMS Convergent Multimedia Services 3 Sorin Georgescu

The Evolution to IMS Multimedia Applications Non-Interactive Multimedia Person-to-Content known usability patterns Photos Video Movies Music Ring tone Internet Streaming Text/Pictures Download Interactive Multimedia HTTP SMS/MMS Person-to-Person dominates traffic growth Active phonebook Video Image Sharing Text Presence Push-To-Talk Voice MMS SMS Voice IMS Convergent Multimedia Services 4 Sorin Georgescu

Watch and Communicate service • While out in town, Bob stopped by at the Jazz festival. He made a short clip and would like to ask his friends if they are interested to go to the evening performance. • He checks the presence information of Alice and Dave. • Bob opens a Chat session and sends the clip to his friends. He asks if they are interested to go to the evening performance. • Dave is watching TV, therefore the chat session is diverted to his IMS enabled STB. Communication services Personalised content services Group and context support IMS Convergent Multimedia Services 5 Sorin Georgescu

IMS – a Standard-based Architecture for NG Services • IMS defines an open IP-based service infrastructure where service intelligence is located in the servers and mobile devices. • IMS as originally specified by 3 GPP, was aiming to enable real-time multimedia services over the IP bearer in GSM and W-CDMA networks. • 3 GPP 2 defined later the MMD for CDMA 2000 networks which is now aligned with IMS. • TISPAN provided the specifications for DSL access. • Cable. Labs provided the specifications for the cable access and now their work together with 3 GPP to incorporate PC 2. 0 specifications into IMS release 8. • Since release 6, interworking with WLAN is supported. If IMS is not used: ü Multimedia communication at best effort ü Service orchestration can be complex ü Service roaming can be difficult to implement ü Provisioning and charging are service specific ü Compliance with LI requirements can be an issue IMS Convergent Multimedia Services 6 Sorin Georgescu

IMS/TISPAN Architecture AS HSS ‘IMS Data’ IM SSF SIP AS SLF Application OSA SCS (SIP AS, OSA AS, CAMEL SE) HLR/Au. C (‘CS/PS’) CSCF BGCF S-CSCF IMS Session Signalling IMS User Plane Data I-CSCF MGCF P-CSCF NASS SPDF/ A-RACF MRF DSLAM UE BAS PDF 3 GPP R 7 / TISPAN R 1 WLAN WAG UE 3 GPP R 6 UE RAN MRFC ALG MRFP Tr. GW WLAN PDG GGSN BB (IPv 4/ IPv 6) PEF IMS GW SGW IMS-MGW IPv 4 PDN (IPv 4 Network) BG IPv 6 PDN (IPv 6 Network) SGSN 3 GPP R 5 IMS Convergent Multimedia Services 7 CS Networks (PSTN, CS PLMN) Sorin Georgescu

Functional Overview (1) • CSCF (Call Session Control Function) consists of 3 separate functions: P-CSCF, I-CSCF, S-CSCF • P-CSCF (Proxy-CSCF): - Entry point to IMS from any access network - Performs integrity protection - Local outbound stateful proxy for all SIP requests/responses, ensuring all signalling is sent via the home network - Includes a Policy Decision Function (PDF) that authorizes bearer resources • HSS (Home Subscriber Server): - IMS subscriber records and service profile - IMS authentication data • I-CSCF (Interrogating-CSCF): - First contact point in home network - Selects assigned S-CSCF - Performs network hiding (THIG) • MRF (Media Resource Function) consists of 2 separate functions: MRFC, MRFP • S-CSCF (Serving-CSCF): - Stateful proxy that provides session control - Performs subscriber authentication - Acts as SIP registrar - Invokes the AS’ (Application Servers) based on IFC (Initial Filter Criteria) • MRFC (Media Resource Function Controller): - Controls media resources in MRFP - Acts as SIP B 2 BUA • MRFP (Media Resource Function Processor): - Media stream processing (transcoding etc. ) - Multimedia announcements - Incoming streams mixing • SLF (Subscriber Location Function): - Look-up function used in networks where multiples HSS’ exist IMS Convergent Multimedia Services 8 Sorin Georgescu

Functional Overview (2) • SIP AS (Application Server): - Hosts IMS native applications • IM SSF (IP Multimedia Switching Service Function): - Provides interworking with CAMEL, ANSI-41, INAP or TCAP services • OSA SCS (Open Service Architecture Service Capability Server): - Provides interworking with OSA services • BGCF (Breakout Gateway Control Function): - Selects the network in which PSTN breakout is to occur and within that network selects the MGCF • SGW (Signaling Gateway): - Performs conversion at transport level (SCCP, SCTP) • SBC (Session Border Controller): • MGCF (Media Gateway Control Function): - Controls media channels in IMS MGW - Performs conversion between ISUP/TCAP and IMS call control protocols • PDF/SPDF (Policy Decision Function / Serving Policy Decision Function): • A-RACF (Access - Resource and Admission Control Function): • IMS MGW (IMS Media Gateway): - Terminates bearer channels from CS networks and PS media streams - Owns/handles resources (echo cancellers, codes, etc. ) IMS Convergent Multimedia Services • NASS (Network Attachment Subsystem): • DSLAM (Digital Subscriber Line Access Multiplexer): 9 Sorin Georgescu

IMS Service Routing – the IFCs I-CSCF Visited A 4 8 Home B 6 9 S-CSCF 10 P-CSCF 3 P-CSCF Visited B Home A S-CSCF 2 7 5 1 IMS AS HSS • SIP requests in IMS architecture always routed to the Home S-CSCF, in both the originating and terminating network. • The S-CSCF uses subscriber’s Service Profile (downloaded during registration), to link-in the SIP AS’ which will process the SIP request. 11 IMS Service Routing = Service Profile based Routing IMS Convergent Multimedia Services • In comparison to IETF SIP Routing where the originator of SIP request may specify a preferred path in the Route header, in IMS the P-CSCF removes this path and ensures that IMS SIP Routing is followed. 10 • The Initial Filter Criteria (IFC) within the Subscriber Profile provide a simple service logic to decide which AS shall be linked-in. These rules are of static nature i. e. they do not change on a frequent basis. Sorin Georgescu

Service/application identification – ICSI/IARI A Communication Service is an aggregation of one or several media components and the service logic managing the aggregation, represented in the protocols used. An IMS application is an application that uses an IMS Communication Service(s) in order to provide a specific service to the end-user. Only IMS applications other than the default application associated to the Communication Service are identified through IARIs. • 3 GPP TS 23. 228 R 7 introduced the ICSI/IARI identifiers as a mechanism for UEs to provide a hint to the network on the AS’ they wish to be linked-in the signalling path. • The introduction of ICSI/IARI in 3 GPP aims to address to a certain extent the limitations due to the use of the Service Profile routing paradigm. The ICSI/IARI are used as parameters in the IFC, therefore the AS selection process becomes more dynamic. IMS Convergent Multimedia Services Appl 1 IARI 1 Appl 2 IARI 2 CS 1 CS 2 ICSI 1 ICSI 2 SIP Stack • The ICSI/IARI provides a mechanism to control rating based on selected pricing model. For example, it is possible to rate differently a Messaging Communication Service when invoked from a Multimedia application then when invoked from a Gaming application. ICSI = IMS Communication Service ID IARI = IMS Application Reference ID CS = Communication Service 11 Sorin Georgescu

Service Convergence in Quadruple Play End User experience = Access to subscribed services from any device in the bundle Industry consolidation and alliances Service continuity = Convergence at Service Provider level. Common provisioning, mgmt and billing Common service and subscriber management Fixed Mobile Convergence = Converged Service Architecture Setup of the appropriate Qo. S and resources IMS Convergent Multimedia Services 12 Sorin Georgescu

Agenda § § § IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and Standardisation Challenges IMS Convergent Multimedia Services 13 Sorin Georgescu

Standardisation fora Multimedia Telephony Presence GLMS Po. C Messaging IP Broadband Access to IMS CSI GSM/WCDMA Access to IMS WLAN Access to IMS Packet. Cable™ Wi. MAX DSL DOCSIS Forum Residential IMS Convergent Multimedia Services Forum Enterprise 14 VCC Mobile Sorin Georgescu

3 GPP R 7 Reference Model TE R MSC GERAN MT C HLR/Au. C* HSS* EIR SMS-GMSC SMS-IWMSC SMS-SC Um Gb, Iu Gr Gf Gs PCRF Gd Iu TE MT R Uu Gn SGSN UE Ga Billing System* Gx+ (Go/Gx) Gmb Gc BM-SC Gi Gn/Gp SGSN UTRAN Rx+ (Rx/Gq) AF GGSN Ga Gi PDN Mb Gy Mb OCS* IMSMGW MRFP Wi CGF* Gm IMS P-CSCF Mw CDF Intranet/ Internet WLAN UE Ww Wu Wa Wa WLAN Access Network Wf Wf Wd 3 GPP AAA Proxy WAG D/Gr Wg Wn HSS* SLF Wx 3 GPP AAA Server Wm Dw Wo Wy Wz CGF* 15 ** OCS* PDG Wp Traffic and signalling Signalling IMS Convergent Multimedia Services Dx Cx HLR/A u. C* Billing System* Note: * Elements duplicated for picture layout purposes only, they belong to the same logical entity in the architecture baseline. ** is a reference point currently missing Sorin Georgescu

TISPAN R 1 Reference Model Application Servers Ut P 1 PSTN/ISDN Emulation logic Sh UPSF PES e 2 Cx Dh P 2 MRFC Gq ' MGCF SGF Ie Gq ' Mn Resource and Admission Control Subsystem GW MRFP S/T Z MG T-MGF IP Transport (Access and Core) IMS Convergent Multimedia Services 16 Ic Mk Mj Mg Iw Sorin Georgescu I-BGF Other IP Networks Mr IBCF Mk BGCF IWF PSTN/ISDN Z Ib Mw/Mk/Mm Mp S/T Charging Functions P 3 Mi P-CSCF Rf /Ro SLF Dx I/S-CSCF Mw Gq ' ISC Mw AGCF Gm Rf /Ro Other types of service logic Ut Network Attachment Subsystem Rf/Ro

WIs in 3 GPP release 7 (02/2008) • Coexistence between TISPAN and 3 GPP authentication schemes study • Service Identification using ICSI/IARI • Liberty Alliance and 3 GPP security interworking • SAE (System Architecture Evolution) • RAN LTE (Long Term Evolution) • Location Services for WLAN interworking • MMTel (Multimedia Telephony) • MRFP-MRFC (Mp) Interface • VCC (Voice Call Continuity) between IMS Vo. IP and CS speech • Parlay X WS: • Message broadcast • Geocoding • Application driven Qo. S • Device Management • Multimedia Streaming/Multicast Control • CSi. CS (Circuit Switched IMS Combinational Service) • SMS/MMS over IP • FBI (Fixed Broadband access to IMS) • IMS Emergency Calls • ISIM API for Java Card • PCC (Policy Control and Charging Evolution) • E 2 E Qo. S • AIPN (All IP Network) Feasibility Study IMS Convergent Multimedia Services 17 Sorin Georgescu

WIs in 3 GPP release 8 (tentative 03/2009) • Architecture impacts of Service Brokering • Enhancements for support of Packet. Cable 2. 0 requirements • Multimedia Priority Service • Personal Network Management • Enhancements for support of machine to machine communication • Enhanced Generic Access Networks • HSPA FDD (Frequency Division Duplex) • Enhancements to SAE/LTE Architecture • OAM&P Studies IMS Convergent Multimedia Services 18 Sorin Georgescu

Agenda § § § IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and Standardisation Challenges IMS Convergent Multimedia Services 19 Sorin Georgescu

IMS in OMA Service Environment context IMS Convergent Multimedia Services 20 Sorin Georgescu

OMA SIMPLE IM Reference Model IMS Convergent Multimedia Services 21 Sorin Georgescu

Limitations of ISC Service Orchestration Model SIP-AS Req URI = A S-CSCF HSS SIP-AS Req URI = B S-CSCF HSS I-CSCF SIP-AS I-CSCF • The application server decides whether to remain linked-in for the whole session by adding its address to the Record-Route SIP header. • If during call handling procedure an AS retargets the SIP request by changing the Request URI, subsequent filter analysis in the S-CSCF is stopped and the S-CSCF forwards the request towards the new target without linking-in the other AS’ specified by IFC. • Application Servers are unaware of the existence of other AS', and whether these will be linked-in. • No service or session state will be passed between application servers unless they use proprietary extensions i. e. are co-designed. • Response messages are routed to the AS’s in the reverse order 1 IMS Convergent Multimedia Services 2 22 Sorin Georgescu

SCIM vs. Service Broker AS AS Camel Services OSA AS OSA API SCIM OSA SCS ISC Sh ISC S-CSCF AS CAP AS IM SSF Sh Cx AS AS Si HSS S-CSCF • The Service Broker architecture has been introduced as WI in IMS Release 8. • The Service Capability Interaction Manager (SCIM) orchestrates service delivery among application servers. • The objective is to provide a coherent and consistent IP multimedia service experience when multiple applications are invoked. • Underspecified in TS 23. 002, the SCIM has become a sort of “magic box” that would solve all issues related to service orchestration. • The work is handled by 3 GPP SA 2 (Architecture) group in TR 23. 810. So far, just the some high level deployment scenarios and some uses cases have been defined. • Possible types of SCIM: • AS Internal SCIM (figure above) • SIP Broker SCIM / Service Broker SCIM • Can be centralised, distributed or hybrid (as in the figure above). • Legacy SCIM IMS Convergent Multimedia Services Service Broker MAP 23 Sorin Georgescu

Parlay X Web Services WS-I Basic Profile: WSDL + SOAP WS-I Secure Profile: WSDL + SOAP + WS-Security • Parlay X Web Services is an abstraction of Parlay WS • Parlay X WS GW acts as a Service Broker SCIM • Enablers which only support WS-I Basic Profile are enhanced with additional WS functionality such as WSSecurity, WS-Policy, WSAddressing • Services defined so far (17) cover: call control, messaging (SMS, MMS), payment, location, geocoding and mapping, presence etc. • Described in WSDL. Service discovery is based on UDDI. IMS Convergent Multimedia Services 24 Sorin Georgescu

Agenda § § § IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and Standardisation Challenges IMS Convergent Multimedia Services 25 Sorin Georgescu

SOA Reference Model What is SOA: A paradigm which defines concepts and general techniques for the design, encapsulation and instantiation of reusable business functions using loosely coupled service interactions SOA Reference Model: ü Service description ü Interaction ü Contract & Policy ü Visibility ü Execution Context SOA Service Description Model ü Real world effect IMS Convergent Multimedia Services 26 Sorin Georgescu

SOA Orchestration Routing based on service identity (equivalent to PSI routing in IMS) Client Service bus functions: SOA Characteristics • Supports an asynchronous message based communication protocol that uses a common format encoding scheme (SOAP/XML) § Services have well defined Service Contracts • Routes, Translates and can Store and Forward exchanged messages • Supports a Discovery mechanism § Services are encapsulated § Services share a message bus and messages exchanged are well documented § Services can be discovered dynamically § Services are loosely coupled § Systems of services are assembled at runtime IMS Convergent Multimedia Services 27 Sorin Georgescu

IMS-SOA Architecture Service Enablers: Service Contract SOA • Provide functionality which can be used by other end-user applications (ex. Location Service) UDDI SOA AS • Unaware of the context in which they are used. Only the consumer service is aware. Service Bus Schema SOAP/XML • Handles the communication between IMS Application Servers and the Service Enablers and the communication with SOA Application Servers. MLP SIP Service Bus MM 7 SB API • Optimized for Server-to-Server communication • Besides providing support for standard open protocols (ex. SOAP), may provide support for Native Interface protocols (ex. MLP, MM 7, SIP etc. ) GW AS IMS AS SB API Enabler CSCF Service Orchestration Orig. network JSR 281 • The consumer AS that invokes the Service Enabler implements the SCIM function. An external Service Broker may be used as well. Heterogeneous Service Bus IMS-SOA Architecture • IMS Service Enablers are invoked from SOA domain through the GW AS. IMS Convergent Multimedia Services IMS 28 Sorin Georgescu

Agenda § § § IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and Standardisation Challenges IMS Convergent Multimedia Services 29 Sorin Georgescu

IMS Core Network § Coexistence of access specific authentication methods § Media Adaptation using UE capabilities discovery § Design of efficient algorithms for real-time adaptation of MBMS content § Access agnostic vs. access aware P-CSCF § Qo. S awareness, access agnostic control of the Qo. S § Media security IMS Convergent Multimedia Services 30 Sorin Georgescu

IMS Service Layer § Service Orchestration paradigms. The integration with SOA architecture § Enhancements to presence service to support device capabilities, subscription state, user preferences, context awareness, bearer state § Multimodal interaction § Payment brokerage § Personalised/interactive advertisement § Qo. S control over the Service Bus. IMS Convergent Multimedia Services 31 Sorin Georgescu

Thank you for your attention! sorin. georgescu@ericsson. com IMS Convergent Multimedia Services 32 Sorin Georgescu