IMS: An Architecture for Convergent Next Generation

IMS: An Architecture for Convergent Next Generation Multimedia Services. Research and Standardisation Challenges Dr. Sorin Georgescu [email protected]

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 Convergence Convergence Societal Societaland andBusiness Businesstrends trends Converged Converged devices devices (Mobile, (Mobile, Internet Internetisisbecoming becomingaamajor majorenabler enabler WLAN, WLAN, Internet Internet etc.) etc.) Connectivity Connectivity of ofcommunications communications Consumers Consumersare areembracing embracing computing, mobile computing, mobileand anddigital digital technology in their everyday technology in their everydaylife life Converged Converged services services Ease Ease of of use use Converged Converged networks networks Reliability, Reliability, Security, Reduced OPEX/CAPEX Security, Reduced OPEX/CAPEX Evolution Evolutionof ofBusiness Businessmodels modelsrequire require increased levels of personal mobility increased levels of personal mobility Converged Converged business business models models Increased margins, Avoidance Increased margins, Avoidance of of twin pitfalls risk Access Technology Enhancements twin pitfalls risk Access Technology Enhancements HSPA HSPA(High (HighSpeed SpeedPacket PacketAccess) Access)––evolved evolved WCDMA WCDMA OFDMA OFDMA(Orthogonal (OrthogonalFrequency FrequencyDivision Division Multiple Access) – 3GPP LTE, WiMAX, Multiple Access) – 3GPP LTE, WiMAX,MBWA, MBWA, ADSL/VDSL, DVB-T/H etc. ADSL/VDSL, DVB-T/H etc. Spatial SpatialProcessing Processing––multi-antennas multi-antennasBase Base Stations supporting advanced spatial Stations supporting advanced spatial processing 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 3GPP, was aiming to enable real-time multimedia services over the IP bearer in GSM and W-CDMA networks. 3GPP2 defined later the MMD for CDMA2000 networks which is now aligned with IMS. TISPAN provided the specifications for DSL access. CableLabs provided the specifications for the cable access and now their work together with 3GPP to incorporate PC 2.0 specifications into IMS release 8. IfIfIMS IMSisisnot notused: used: Multimedia communication at best effort Multimedia communication at best effort Service orchestration can be complex Service orchestration can be complex Service roaming can be difficult to implement Service roaming can be difficult to implement Provisioning and charging are service specific Provisioning and charging are service specific Since release 6, interworking with WLAN is supported. Compliance with LI requirements can be an issue 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/AuC (‘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 3GPP R7 / TISPAN R1 WLAN WAG UE 3GPP R6 UE RAN BAS PDF WLAN PDG GGSN MRFC ALG MRFP TrGW BB (IPv4/ IPv6) PEF IMS GW SGW IMS-MGW IPv4 PDN (IPv4 Network) BG IPv6 PDN (IPv6 Network) SGSN 3GPP R5 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) 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) SLF (Subscriber Location Function): - Look-up function used in networks where multiples HSS’ exist IMS Convergent Multimedia Services 8 MRF (Media Resource Function) consists of 2 separate functions: MRFC, MRFP MRFC (Media Resource Function Controller): - Controls media resources in MRFP - Acts as SIP B2BUA MRFP (Media Resource Function Processor): - Media stream processing (transcoding etc.) - Multimedia announcements - Incoming streams mixing Sorin Georgescu

Functional Overview (2) SIP AS (Application Server): - Hosts IMS native applications IM SSF (IP Multimedia Switching Service Function): - Provides interworking with CAMEL, ANSI41, 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) 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 SBC (Session Border Controller): NASS (Network Attachment Subsystem): DSLAM (Digital Subscriber Line Access Multiplexer): 9 Sorin Georgescu

6 I-CSCF Visited A 4 8 9 S-CSCF 10 P-CSCF 3 P-CSCF Visited B Home A S-CSCF 2 7 5 1 IMS AS HSS IMS AS HSS 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. SIP requests in IMS architecture are 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 Home B IMS Service Routing – the IFCs 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. 3GPP 3GPPTS TS23.228 23.228R7 R7 introduced the ICSI/IARI introduced the ICSI/IARI identifiers identifiersas asaamechanism mechanismfor for UEs to provide a hint to the UEs to provide a hint to the network networkon onthe theAS’ AS’they theywish wish totobe linked-in the signalling be linked-in the signalling path. path. The Theintroduction introductionofof ICSI/IARI ICSI/IARIinin3GPP 3GPPaims aimstoto address addresstotoaacertain certainextent extent the limitations due to the the limitations due to theuse use ofofthe Service Profile routing the Service Profile routing paradigm. paradigm.The TheICSI/IARI ICSI/IARIare are used as parameters in the used as parameters in the IFC, IFC,therefore thereforethe theAS AS selection process becomes selection process becomes more moredynamic. dynamic. IMS Convergent Multimedia Services Appl 1 IARI1 Appl 2 IARI2 IARI2 CS 1 CS2 ICSI1 ICSI2 SIP Stack ICSI IMS Communication Service ID The TheICSI/IARI ICSI/IARIprovides providesaa mechanism mechanismtotocontrol controlrating rating based on selected pricing based on selected pricing model. model.For Forexample, example,ititisis possible possibletotorate ratedifferently differentlyaa Messaging MessagingCommunication Communication Service when Service wheninvoked invokedfrom from aaMultimedia application Multimedia application then thenwhen wheninvoked invokedfrom fromaa Gaming Gamingapplication. application. 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 Convergence at Service Provider level. Service continuity Common provisioning, mgmt and billing Common service and subscriber management Fixed Mobile Convergence Converged Service Architecture IMS Convergent Multimedia Services Setup of the appropriate QoS and resources 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 PoC Messaging IP Broadband Access to IMS CSI GSM/WCDMA Access to IMS WLAN Access to IMS PacketCable WiMAX Forum DSL DOCSIS Forum Residential IMS Convergent Multimedia Services Enterprise 14 VCC Mobile Sorin Georgescu

3GPP R7 Reference Model TE R MSC GERAN MT C HLR/AuC* 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 CSCF Mw CDF Intranet/ Internet WLAN UE Ww Wu Wa Wa WLAN Access Network Wf Wf Wd 3GPP AAA Proxy WAG Wn HSS* D/Gr Wg SLF Wx 3GPP AAA Server Wm Dw Wo Wy Wz CGF* ** OCS* PDG Wp Traffic and signalling Signalling IMS Convergent Multimedia Services Dx Cx HLR/ AuC* 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 15 Sorin Georgescu

TISPAN R1 Reference Model Application Servers Ut PSTN/ISDN Emulation logic Sh UPSF PES e2 e2 P1 AGCF ISC Dh Cx Dx Mw P2 IBCF Mj MRFC Mg Gq' MGCF Ie Gq' Mn Resource and Admission Control Subsystem GW MRFP S/T Z MG SGF T-MGF IP Transport (Access and Core) IMS Convergent Multimedia Services Iw Ic 16 Sorin Georgescu I-BGF Other IP Networks Mk BGCF PSTN/ISDN Z Ib P3 IWF Mk Mp S/T SLF Mr Gq' Rf/Ro Mi P-CSCF Charging Functions Mw/Mk/ Mm I/S-CSCF Mw Gm Rf/Ro Other types of service logic Ut Network Attachment Subsystem Rf/Ro

WIs in 3GPP release 7 (02/2008) Coexistence between TISPAN and 3GPP authentication schemes study Service Identification using ICSI/IARI Liberty Alliance and 3GPP 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 VoIP and CS speech Parlay X WS: Message broadcast Geocoding Application driven QoS Device Management Multimedia Streaming/Multicast Control CSiCS (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) E2E QoS AIPN (All IP Network) Feasibility Study IMS Convergent Multimedia Services 17 Sorin Georgescu

WIs in 3GPP release 8 (tentative 03/2009) Architecture impacts of Service Brokering Enhancements for support of PacketCable 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 Applications OSE Context I0 P SP Domain Policy Enforcer Execution Environment Execution Environment I0 (Software Life Cycle Mgmt, Load balancing, Caching, O&M, etc.) Service Binding Service Binding Service Binding Service Binding Service Enabler Service Enabler Service Enabler Service Enabler I1 I2 ISC Sh Ut IMS Convergent Multimedia Services Ro Rf 20 Gm Mb NonIMS Sorin Georgescu (Software Life Cycle Mgmt, Load balancing, Caching, O&M, etc.)

OMA SIMPLE IM Reference Model XDM Client XDM -5 Aggregation Proxy XDM -3 PRS-7 XDM-4 IM-12 IM XDMS PRS-6 Presence XDMS XDM-7 XDM-2 IM Client IM-1 Shared Profile XDMS Shared Group XDMS Shared XDMSs PRS-3 CH-1 IM -3 IM -2 PRS-8 Shared List XDMS PRS-2 Charging IM-6 IM-5 SIP / IP Core Pres Client: Watcher Search Proxy IM Server IM -4 IM -11 IM -10 PRS-5 Presence Server IM-8 IM -7 IP-1 IM-9 DMC DM-1 DMS IMS Convergent Multimedia Services 21 Sorin Georgescu Remote SIP/IP Core XDM -1 PRS-1 Pres Client: Source XDM-6 Remote IM Server Remote IM Client

Limitations of ISC Service Orchestration Model SIP-AS SIP-AS SIP-AS 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 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 3GPP SA2 (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 Service Broker MAP 23 Sorin Georgescu

Parlay X Web Services WS-I Basic Profile: WSDL SOAP Parlay X Web Services is an abstraction of Parlay WS WS-I Secure Profile: WSDL SOAP WS-Security AS Trusted Domain AS Parlay-X, Customized interfaces AS AS WS Security, WS-Addressing Customized Compound WS Parlay-X WS GW IMS Service Enablers Sh ISC H.248 HSS CSCF Media resources 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 Core Network 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 Whatis isSOA: SOA: AAparadigm paradigmwhich whichdefines definesconcepts concepts and andgeneral generaltechniques techniquesfor forthe the design, encapsulation and design, encapsulation and instantiation instantiationof ofreusable reusablebusiness business functions using loosely coupled functions using loosely coupled service serviceinteractions interactions Visibility Service SOA SOAReference ReferenceModel: Model: Service Service Service Servicedescription description Interaction Interaction Real world effect Service Interface Functionality Interaction Contract & Policy Contract Contract&&Policy Policy Visibility Visibility Execution ExecutionContext Context Information model Behavior model SOA Service Description Model Real Realworld worldeffect effect IMS Convergent Multimedia Services Service Description Reachability 26 Sorin Georgescu

SOA Orchestration Appl 1 Client Terminal Application 1 Enabling Service 1 Enabling Service 2 Enabling Service 3 Routing based on service identity (equivalent to PSI routing in IMS) AS1 Application 2 AS2 Service Servicebus busfunctions: functions: Supports Supportsan anasynchronous asynchronousmessage message based communication protocol based communication protocolthat that uses a common format encoding uses a common format encoding scheme scheme(SOAP/XML) (SOAP/XML) Routes, Routes,Translates Translatesand andcan canStore Store and andForward Forwardexchanged exchangedmessages messages Supports SupportsaaDiscovery Discoverymechanism mechanism IMS Convergent Multimedia Services Enabling Service 4 AS3 SOA SOACharacteristics Characteristics Services have well defined Service Contracts Services have well defined Service Contracts Services are encapsulated Services are encapsulated Services share a message bus and messages Services share a message bus and messages exchanged exchangedare arewell welldocumented documented Services can be discovered dynamically Services can be discovered dynamically Services are loosely coupled Services are loosely coupled Systems of services are assembled at runtime Systems of services are assembled at runtime 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 MM7 SB API 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, MM7, SIP etc.) GW AS IMS AS SB API Enabler CSCF Service Orchestration Orig. network The consumer AS that invokes the Service Enabler implements the SCIM function. An external Service Broker may be used as well. IMS Service Enablers are invoked from SOA domain through the GW AS. IMS Convergent Multimedia Services 28 IMS JSR 281 Heterogeneous Service Bus IMS-SOA Architecture 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 QoS awareness, access agnostic control of the QoS 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 QoS control over the Service Bus. IMS Convergent Multimedia Services 31 Sorin Georgescu

Thank you for your attention! [email protected] IMS Convergent Multimedia Services 32 Sorin Georgescu