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pdfslide.net_ims-enabling-services-wherever-the-customer-and-whatever-the-access-duncan.ppt
- 1. IMS - enablingservices, wherever the customer and whatever the access Duncan Mills - Vodafone Stuart Walker – Leapstone Sponsored by
- 2. Copyright 2005: MultiServiceForum Agenda • From NGN to Fixed Mobile Convergence • 3GPP and TISPAN overview • The IMS Architecture • Service Layer • MSF and IMS • Q&A
- 3. Copyright 2005: MultiServiceForum Where has NGN come from? • In fixed line there has been a long term move towards a VoPacket replacement for PSTN • Driver has always been to reduce Opex in fixed line networks by optimising bandwidth usage, whilst replacing outdated TDM switching fabric. – Compressed speech into less than 64kbps channels – Further optimisation using VAD, Silence Suppression, AAL2 or IP multiplexing yields significant reduction in core network bandwidth requirements. • Drivers in 3GPP are more service related – IMS is borne out of a need for ‘feature rich’ service – Bandwidth requirements and their impact on capacity on the Radio interface are actually worse than now. • Now, IMS possibly provides the final piece in the business case for NGN that makes the decision to move justifiable… FIXED MOBILE CONVERGENCE
- 4. Copyright 2005: MultiServiceForum Different drivers = same end goal? • If fixed wants OpEx saving and fabric replacement, but mobile wants new services, how come the answer is the same architecture for both? – Both sides see the advantage to common, seamless services over any access. – IMS is defined in 3GPP so it has all the requirements for mobile operators built in. – SIP controlled voice is already available in fixed networks (particularly for enterprise customers) so it extends existing technology. • However, an IMS deployment supporting only voice does not make sense – Mobile has to go from no installed base to the full suite of available service to be justifiable. – IMS delivering single services (voice, PoC etc) is too expensive and too limiting in the service set it facilitates
- 5. Copyright 2005: MultiServiceForum Who gains from Fixed and Mobile convergence? • Manufacturers – Single development stream reduces R&D costs – Next gen. networks = next gen. device = new revenue streams – to deploy it, operators have to buy it! • Has to be priced to make initial CapEx recovery for the operator a short term deliverable. • Operators – Optimised ‘all IP’ network reduces OpEx – Opens the fixed market’s customers to mobile operators and vice versa. – Next Gen Services = new revenue streams – to use it, the customers have to buy it • Has to be the right service set, priced to make the services attractive to the customer
- 6. Copyright 2005: MultiServiceForum Who gains from Fixed and Mobile convergence? • End Users – Common service set available regardless of device they use, the location they are in or the access medium they are using. – New services available – location based, blended interfaces combining multiple inputs into a single presentation. – Single sign on – one identity that goes everywhere with you. BUT The food chain runs from the End User upwards. What services do they want? When will they buy them? At what price point?
- 7. Copyright 2005: MultiServiceForum 3GPP IMS - Architecture I-CSCF AS OSA- GW IM- SSF MGCF P-CSCF GGSN PDF Gm Sh Cx Si ISC Mw Mw Mi Mb Mj Mr Mm Mb Multimedia Content Mk Legacy Bearer ISUP or BICC MRFC UE MRFP Gm HSS BGCF IM-MGW Mg SLF Dx Dh Gq Go Mp Mn 3GPP Profile SIP Other Control Plane Bearer Legacy protocol S-CSCF
- 8. Copyright 2005: MultiServiceForum TISPAN – Top Level Architecture Taken from TISPAN WI02007 (Overall Functional Architecture) Other net works Other subsystems Core IMS PSTN/ISDN Emulation subsystem Customer Premises Equipment Service Layer Transport Layer Transfer Functions Resource and Admission Control Subsystem Network Attachment Subsystem Applications User profiles
- 9. Copyright 2005: MultiServiceForum TISPAN – IMS Core Taken from TISPAN WI02029 (Functional Architecture IMS) Other IP Networks IP Transport (Access and Core) T-MGF I-BGF AS UPSF P-CSCF I/S-CSCF BGCF SLF Charging Functions IWF UE « Core IMS» Mw Mw/Mk/Mm Mr Mg Mj Mi Mp Mn Gm Gq ISC Cx Dx Dh Sh Ic Rf/Ro Rf/Ro Ib Ia Id PSTN/ISDN SGF MRFC MGCF MRFP Resource and Admission Control Subsystem Network Attachment Subsystem If Ie Mw IBCF Mk Mk
- 10. Copyright 2005: MultiServiceForum TISPAN NGN mapped on to 3GPP IMS +TISPAN add ons I-CSCF AS OSA- GW IM- SSF MGCF P-CSCF GGSN PDF Sh Cx Si ISC Mw Mw Mi Mb Mj Mr MRFC UE MRFP Gm HSS BGCF IM-MGW (T-MGF) Mg SLF Dx Dh Gq Go Mp Mn S-CSCF SGF I-BCF I-BGF IWF PSTN/ISDN Other IP Networks IMS Core Transport NASS Applications RACS CLF, UAAF, PDBF, UPSF SPDF A-RACF, SPDF L2TF, RCEF, AMF None of these functions are included in the 3GPP architecture RACS
- 11. Copyright 2005: MultiServiceForum 3GPP IMS applicability to NGN • In R6, 3GPP IMS has been made ‘Access Independent’ – the technology used to transport SIP messages to the edge of the IMS network does not affect the functionality within the IMS network itself. • This allows IMS to be applied to any form of Access technology that is capable of transporting SIP control messages to the P-CSCF – WLAN, DSL, Cable Modem, FTTx, Satellite, Broadband Wireless all become irrelevant – all that matters is SIP presentation to the P-CSCF. – Only aspect of Access that is relevant is User Equipment capability and QoS. P-CSCF I-CSCF MRF MGW MGCF IMS S-CSCF SIP Application Servers SIP Application Servers HSS
- 12. Copyright 2005: MultiServiceForum Access Independence of IMS RNC MSC(Server) SGSN GGSN CN MGW BSC UMTS/GPRS WLAN Corporate P-CSCF I-CSCF MRF MGW MGCF IMS S-CSCF SIP Application Servers SIP Application Servers HSS CDMA 2000 DSL/Cable Modem DSLAM/CMTS
- 13. Copyright 2005: MultiServiceForum IMS as a common ‘middleware’ layer MRF IMS Core RNC MSC(Server) SGSN GGSN CN MGW BSC UMTS/GPRS SIP Application Servers P-CSCF I-CSCF S-CSCF HSS SIP Application Servers SIP Application Servers IMS Applications MGCF BGCF MGW VoIP Interworking Elements IP Bearer Network
- 14. Copyright 2005: MultiServiceForum IMS Nodes (1/2) Database Elements – HSS (Home Subscriber Server) – SLF (Subscription Locator Function) IMS Control Elements – CSCF (Call Session Control Function) – S-CSCF (Serving CSCF) – P-CSCF (Proxy CSCF) – I-CSCF (Interrogating CSCF) Control Plane Interworking Elements – MGCF (Media Gateway Control Function) – BGCF (Breakout Gateway Control Function) – SGW (Signaling Gateway) IM-SSF I-CSCF MRF MGW MGCF HSS CSE(SCP) SIP Application Servers OSA-SCS sgw OSA Application Server S-CSCF P-CSCF BGFC
- 15. Copyright 2005: MultiServiceForum IMS Nodes (2/2) IM-SSF I-CSCF MRF MGW MGCF HSS CSE(SCP) SIP Application Servers OSA-SCS sgw OSA Application Server S-CSCF P-CSCF BGFC IMS Service Elements – AS (Application Server) External Service and Service Interworking Elements – OSA Elements - SCS (OSA Service Capability Server, OSA Framework, OSA Application Server – CAMEL elements - IM-SSF (IP Multimedia Switching Service Function), CSE (CAMEL Service Environment) Resource Elements – Media Resources Function (MRF) Media Interworking Elements – MGW (Media Gateway)
- 16. Copyright 2005: MultiServiceForum Benefits of a SIP control plane • SIP is an end-to-end signalling protocol used to establish, modify and tear down IP sessions • The IMS nodes can remain in this SIP signalling path throughout a session, ensuring that the network is always aware of the service: – Allowing the network to control the QoS of the bearer – Allowing the network to invoke rich services on behalf of the user – Allowing for traditional and new charging models (e.g. duration-based, A-party pays, A-party pays for the voice, B-party pays for the video etc)
- 17. Copyright 2005: MultiServiceForum “So what ?”- says the subscriber Infrastructure with no clear application….. this wouldn’t be the first time
- 18. Copyright 2005: MultiServiceForum Service Co-ordination Service Orchestration Service Brokerage Service Control IN with the benefit of hindsight
- 19. Copyright 2005: MultiServiceForum SIP based service orchestration – Service Velocity and Service Agility Penetration (number of subscribers using service) Duration (active service lifetime) Traditional Telco Services Short Lived Services Niche Market Services Service Velocity – new applications and services to market quicker to address the short lived service market Service Agility – flexibly bundle applications into customer products to address niche subscriber markets New market – economically realizable through faster and more flexible service layer
- 20. Copyright 2005: MultiServiceForum IMS Service Orchestration Model S-CSCF Parlay App gsmSCF ISC ISC ISC CAMEL OSA API OSA SCS IM-SSF SIP Application Server Mw P/I CSCF HSS Cx Sh Si MAP Session Control Service Orchestration Service Logic Service Interaction Management S-CSCF - Subscriber service profile pulled from HSS at Registration time. Multiple profiles per subscriber (profile per alias) Profile is a list of priority ordered services point triggers SPT. SPT = boolean expression using SIP Method SIP Headers and Contents Session Case SDP contents Service Interactions handled through a SCIM function, depicted as part of the SIP AS although not really defined. Service profile updates pushed to S- CSCF from HSS.
- 21. Copyright 2005: MultiServiceForum MSF R2 Service Orchestration Model Call Agent Service Broker Parlay App IF 9 IF 9 IF 9 IF 11 Parlay / Parlay X Gateway Service Logic Gateway SIP Application Server IF 7 Session Control Service Orchestration Service Logic Service Interaction Management ParlayX App IF 12 Other Application Environments Call Agent Invokes Service Broker on originating and or terminating side of call. Call Agent can apply embedded service logic before and after invocation of Service Broker. Service Broker engaged set of priority ordered applications on seven ‘trigger’ conditions (oCallAttempt, oBusy, oNoAnswer, oHangup, tCallAttempt, tBusy, tNoAnswer) Conflict resolution / Interaction handling implied but not defined. Permit multiple applications per link in SIP chain for efficiency.
- 22. Copyright 2005: MultiServiceForum Shared Service Data Diameter Sh Diameter Sh Diameter Sh HSS Shared Network Database Buddy Lists Address Books Prepaid Balance etc Application Servers HSS provides a shared network data repository allowing applications to share subscriber data. In multi-HSS deployments, Dh interface to SLF is used to locate correct HSS for subscriber. Sh interface (Diameter) - operations Sh-Pull (read data) Sh-Update (modify data) Sh-Subs-Notify (request notification of data change) Sh-Notify (notification of change) Defined Data Sets Repository Data – opaque data, network defined IMS Public Identity IMS User State S-CSCF Name Initial Filter Criteria Location Information User State Charging Information MSISDN
- 23. Copyright 2005: MultiServiceForum Parlay and ParlayX Parlay X API’s Common Third Party Call Call Notification Short Message Multimedia Messaging Payment Account Management Terminal Status Terminal Location Call Handling Audio Call Multimedia Conference Address List Management Presence Parlay API’s Framework Call Control Generic Multi-party Multi-Media Conference Content Based Charging Terminal Capabilities Presence and Availability Policy Management Data Session Control Account Management User Interaction Mobility Management Generic Messaging Multimedia Messaging Address List Management Presence Network Elements Parlay Gateway Parlay X Web Services Parlay Applications Parlay X Applications Network Protocols (e.g. SIP, INAP, etc) Parlay API’s Parlay X APIs
- 24. Copyright 2005: MultiServiceForum SIP AS Multiple mechanisms exist for creating SIP applications. SIP-CPL – Call Processing Language. An XML based scripting language for controlling call services. Designed to be implemented on either network servers or user agent servers via a lightweight CPL interpreter. Limited but safe, no variables, no loops, no ability to run external programs. SIP-CGI – Common Gateway Interface. Like HTTP CGI, the script resides in a network server and passes message parameters through environment variables and sends instructions back via the standard output. CGI scripts can be written in most programming languages. SIP Servlet – Servlets are similar to GCI but rather than a separate process messages are passed to class that runs in the JVM on the server. As they are Java based SIP servlets should be portable between server platforms. JAIN SIP – A low level API that maps directly to the SIP RFC. JAIN SIP Lite – A high level API; uses a greater degree of protocol abstraction and acts as a high level wrapper around the SIP protocol. Requires much less knowledge of the SIP protocol on the part of the developer than JAIN SIP.
- 25. Copyright 2005: MultiServiceForum Legacy Service Access via IMS-SSF SSF function SIP Proxy or B2BUA SIP INAP / TCAP SIP IM-SSF function allows access to legacy IN services from the SIP service network. Acts as a proxy in the SIP domain and as an SSP in the IN domain. Effectively peers SIP to ISUP and applies the SSP functions. Only works in one direction, i.e. IN services on a SIP network. Realistically some legacy services may require SIP-I to be delivered to the IM- SSF in order to prevent information loss. IM-SSF products are commercially available.
- 26. Copyright 2005: MultiServiceForum Other Service Models Service Delivery Platforms SDP No consensus to date on what architectural elements constitute an SDP Some vendors use the term SDP for their application servers or content delivery solutions, whereas other vendors and service providers tend to include a whole portfolio of products and components such as CRM systems or rating engines in their SDP offering. In general, an SDP should be seen as a commercial bundle of different products, possibly offered by different vendors. Some comment elements of SDPs are :- • Service Execution Platform (e.g. Application Server) - a core element of an SDP providing the deployment and execution environment for broad range of voice and data applications. • Network Abstraction Layer (e.g. Parlay GW ) - a core element of an SDP providing standardized interfaces to core network elements and services. • Service Exposure Layer (e.g. Parlay X GW) - an optional element exposing service capabilities (usually via Web Services) to 3rd party service providers and enterprises. • Content Delivery Platform - an optional element usually present in mobile SDPs for the provisioning of multimedia content to mobile devices. Network Elements Web Services Service Exposure Layer Network Abstraction Layer Service Execution Platform Content Delivery Platform
- 27. Copyright 2005: MultiServiceForum OSE (OMA Service Environment) Main components Application – either in house or third party Policy Enforcer – applies policies (authorization, authentication, ..) to the interaction between the Application and the Enabler or between Enablers. Enabler – Intrinsic functions providing access to the underlying network resources. OMA only define interfaces not individual methods for the enabler. Execution Environment – provides Life Cycle, Load Balancing and other OA&M functions.
- 28. Copyright 2005: MultiServiceForum Service Orchestration – tricky stuff
- 29. Copyright 2005: MultiServiceForum Media Specific Applications - SDP Modification Insulate Applications from the full media awareness – present to them only the media parameters appropriate to their function. Authentication App Voice App Video App Whiteboard App Service Orchestration Function INVITE m=audio m=video m=application INVITE m=audio m=video m=application INVITE m=audio m=video m=application INVITE m=audio INVITE m=audio INVITE m=video INVITE m=video INVITE m=application INVITE m=application INVITE m=audio m=video m=application Audio Video Application SDP Audio Video Application SDP Audio Video Application SDP Audio Video Application SDP Audio Video Application SDP STORE EXTRACT EXTRACT STORE STORE STORE STORE EXTRACT EXTRACT EXTRACT Treat as a single service chain, SDP ‘components’ updated as the chain progresses. Parallel invocation could reduce latency but needs potentially complex rules to re- combine multiple SIP INVITEs to the destination.
- 30. Copyright 2005: MultiServiceForum Partial Media Terminating Applications Applications may terminate the media session (directly or via a shared media server). In such cases there is no onward signalling from the application. However, the application may have only terminated a single media type; in such cases the Service Orchestration Function should ‘fork’ the INVITE and continue with session establishment and service invocation for the remaining media types. Authentication App Voice App Video App Whiteboard App Service Orchestration Function INVITE m=audio m=video m=application INVITE m=audio m=video m=application INVITE m=audio m=video m=application INVITE m=audio INVITE m=audio INVITE m=video INVITE m=video INVITE m=application INVITE m=application INVITE m=video m=application Audio Video Application SDP Video Application SDP Video Application SDP Video Application SDP Audio Video Application SDP STORE EXTRACT EXTRACT STORE REMOVE STORE STORE EXTRACT EXTRACT EXTRACT Audio MCU INVITE (conf=xxx) m=audio
- 31. Copyright 2005: MultiServiceForum MSF Release 2+ (IMSF) - Objectives Import IMS functions into the R2 architecture in order to :- • Support nomadicity (roaming) of terminals and users. • Support inter working between core IMS and MSF R2+ – Roaming of IMS subscriber to R2+ network – Roaming of R2+ subscriber to IMS network
- 32. Copyright 2005: MultiServiceForum MSF Release 2+ (IMSF) – Architectural Snapshot AG TG SG SBG-NE DCA SCA RCA SBG-NC SB BM MS HSS AS PGW SLG PA PXA AG = Access Gateway TG = Trunking Gateway SG = Signalling Gateway SCA = Static Call Agent DCA = Dynamic Call Agent RCA = Routing Call Agent MS = Media Server SBG = Session Border Gateway BM = Bandwidth Manager SB = Service Broker HSS = Home Subscriber Server AS = Application Server PGW = Parlay(x) Gateway SLG = Service Logic Gateway PA = Parlay Application PXA = Parlay X Application P-CSCF S-CSCF I-CSCF SCIM OSE IM-SSF SDP OSA SCS 1st Gen VoIP End Points IMS End Points
- 33. Copyright 2005: MultiServiceForum A typical example of a rich voice call • A has a subscription with fixed operator X • B has a subscription with mobile operator Y • B is roaming to mobile network Z • A calls B – voice call – A has originating services, B has terminating services • B adds in video – A has terminating services • A adds in white-boarding – A has originating services
- 34. Copyright 2005: MultiServiceForum A typical example of a rich voice call User B DSL/Cable Modem DSLAM/CMTS RNC GGSN Network Z UMTS/GPRS Network X MSF R2+ User A SGSN Network Y IMS GRX SBG-NE P-CSCF P-CSCF RCA I-CSCF I-CSCF S-CSCF DCA S-CSCF HSS HSS AS AS
- 35. Copyright 2005: MultiServiceForum Summary • IMS offers the ability to rapidly define and implement services that interact with each other seamlessly, regardless of the access technology and location of the end user. • Subscribers have their services available to them on multiple types of end user device and with common presentation and identification. • The access technology no longer governs the service presentation to the end user, and so a vast new range of services is conceivable.
- 36. Copyright 2005: MultiServiceForum Q & A Thanks to our sponsors