세션제어프로토콜기술 2006. 2. 23 삼성전자
목차 Overview IMS features IMS Subscription ID & Service Trigger IMS QoS IMS Charging Architecture IMS evolution SAMSUNG Electronics Co., Ltd. 1
Overview FMC Is Introduction of IMS 3GPP IMS Reference Model
FMC Is 사업자의 Resource( 통신망 / 서비스 / 장비 / 인력등 ) 를 상호보완적으로 Converge 하여 사업자및고객에게새로운가치를창출 Commercial Convergence N/W & Service Convergence Device Convergence Marketing & Channel Marketing Biz Management Management Bundle Service Bundle Service Single Bill Charging IMS Core N/W Standard Service (OMA, IETF, 3GPP) Open Interface (SIP,Parlay) Multi-Band All IP Device Multi-Mode Multi-Band Device Multi-Media Wide-Band Device (TPS+Broadcast) SAMSUNG Electronics Co., Ltd. 3
Introduction of IMS IMS introduced in UMTS Rel5, and further enhanced in Rel6: IP Multimedia domain for call control based on SIP 3GPP specifies features to fullfill operator requirements, e.g.: QoS control Charging Security Subscription profiles Interworking with other networks (CS/PSTN) IMS provides building blocks allowing faster integration and deployment of IP multimedia services SAMSUNG Electronics Co., Ltd. 4
3GPP IMS Reference Model PSTN IP Multimedia Networks AS : Application Legacy Server Signaling Networks BGCF : Breakout Gateway Control Function Mm CAP CAP : CAMEL PSTN PSTN Application Part IM OSA BGCF CSCF GGSN : Gateway SSF AS GPRS Support Node Mb Mb Mk Mi ISC HSS : Home Mj Mw OSA-API Subscriber Function ISC CSCF : Call Session Control Function IMS OSA Mn MGCF Mg CSCF ISC AS MGCF : Media MGW SCS Gateway Controller Function Mb MGW : Media Mr Mw Dx Cx Gateway MRFC : Multimedia MRFP Mp MRFC Proxy Resource Function SLF HSS CSCF Controller MRFP : Multimedia Resource Function Mb Mb Go Gm Processor OSA : Open Services Mb Architecture GGSN UE SCS : Service Capability Server SLF : Subscription SAMSUNG Electronics Co., Ltd. Locator Function 5
IMS features (3GPP release 5/6) IMS in Release-5 IMS Phase 2 Release 6
IMS in Release-5 IP Multimedia Core Network Subsystem (IM Rel-5 S) IP Multimedia Core Network Subsystem (IMS) became part of 3GPP Uses SIP (Session Initiation Protocol) as the protocol for session management SIP is standardised by IETF (RFC-3261) Main SIP functionality: Setup, Modify and Tear down of multi-media Sessions Request and deliver presence information Instant messaging Works with URI s Uniform Resource Indicators, which might be location independent User related URI, also called AOR Address of Record This you store in your address book Device URI Associated to a user for a shorter period of time SAMSUNG Electronics Co., Ltd. 7
IMS Phase 2 Release 6 Main Work Items for IMS Phase 2: IMS Conferencing IMS Messaging IMS Group Management Additional SIP capabilities (e.g. forking) Interworking with IP networks: IETF SIP and IPV4 networks Interworking between IMS and CS networks Local Services Other WIs: Interworking and migration scenario for IPv4 based IMS QoS improvements (Gq) 3GPP enablers for services like PoC IMS Commonality and Interoperability Flow-Based Charging SAMSUNG Electronics Co., Ltd. 8
IMS Subscription ID & Service Trigger IMS Subscription & ID Service Triggering Architecture for IMS Filter Criteria (TS 23.218) Service Point Triggers (TS 23.218)
IMS Subscription & ID Private User Identity Public User Identity 1 Public User Identity 2 Implicitly Registered ID Set 1 Service Profile 1 Service Profile 2 IMS Subscription Public User Identity 3 Public User Identity 4 Implicitly Registered ID Set 2 Service Profile 3 Private User Identity Public User Identity 5 Public User Identity 6 Implicitly Registered ID Set 3 Service Profile 4 SAMSUNG Electronics Co., Ltd. 10
Service Triggering Architecture for IMS Application Server Service Logic Service Platform Trigger Points HSS SIP Interface ifc sfc SIP S-CSCF SIP S P T Filter Criteria SIP SAMSUNG Electronics Co., Ltd. 11
Filter Criteria (TS 23.218) Filter Criteria (FC) Information which the S-CSCF receives from the HSS or the AS that defines the relevant SPTs for a particular application. Initial Filter Criteria (ifc) 서비스를제공받을 AS 로트리거링하기위한조건등을정의 (HSS 로부터수신 ) Subsequent Filter Criteria (sfc) AS 를통한서비스수행중, 서비스제공에필요한 dynamic 한트리거링정보를정의 (AS 로부터수신 ) 규격에서의서비스처리기본원칙 S-CSCF 는 session control 만수행 ifc 를이용하여 AS 로트리거링을수행, AS 를통하여서비스제공 SAMSUNG Electronics Co., Ltd. 12
Service Point Triggers (TS 23.218) Service Point Triggers (SPTs) Service Point Triggers (SPTs) are those points in the SIP signalling on which Filter Criteria can be set Any Initial known or unknown SIP method (e,g, REGISTER, INVITE, SUBSCRIBE, MESSAGE) Presence or absence of any header field Content of any header field or Request-URI Direction of the request is with respect to the served user MO or MT to registered user MT to unregistered user REGISTER is considered part if the MO The S-CSCF shall verify if the end user is barred before checking if any trigger applies for that end user Session description information SAMSUNG Electronics Co., Ltd. 13
IMS QoS IMS based QoS Network Elements Requirement for IMS QoS
IMS based QoS (1/3) IMS based QoS Supports a minimum bandwidth required by service based on PDF s QoS decision and IP Edge node s (e.g., GGSN, PDSN, ACR) resources PDF s QoS decision based on IMS QoS signaling and the operator s policy rules Supports maximum bandwidth if resources are available IMS based QoS Definition UE demands required QoS for service Application level E2E QoS negotiation End-to-end QoS requirements are negotiated via SIP/SDP Signaling Service Admission Control (SAC) Managing session related resources (IP Edge Node) Authorizing the bandwidth allocation request based on end-to-end negotiated QoS requirement and Operator s policy rules (PDF) SAMSUNG Electronics Co., Ltd. 15
IMS based QoS (2/3) Mechanism for E2E QoS authorization SDP Inspection SDP media parameters are examined based on local policy, configuration of operators or user subscription If there are any media parameters which are not allowed on the network, CSCF return a 4XX (Not Acceptable HERE) response. UE, P-CSCF, S-CSCF, and AS perform SDP inspection Session Based Local Policy (SBLP) based QoS authorization P-CSCF generates the service information from SDP and sends it to PDF PDF authorizes the QoS requirements from IMS-Proxy based on operator policy rules PDF creates and saves SBLP that reflects authorization results. PDF authorizes the QoS requirements from IP Edge node based on SBLP SAMSUNG Electronics Co., Ltd. 16
IMS based QoS (3/3) SDP SDP Inspection UE P-CSCF S-CSCF AS SDP SDP inspection performs based on Local Policy. QoS QoSauthorization based based on on SBLP SBLP SDP inspection performs based on Local Policy or User Subscription AS checks SDP and request confirmation for the resource reservation at the endpoint. 2. QoS negotiation 1. SDP from UE1 3-4. SDP from UE2 4.Second PDP Context Setup Req 8. Second PDP Context Setup Res 5. Bearer Authorization request 7. Bearer Authorization response Go P-CSCF Gq SBLP PDF Local Policy 3-1. Service Information 3-3 Auth token 3-2. QoS authorization, Create SBLP 6. QoS authorization based on SBLP UE1 GGSN 9. QoS Commit UE2 8. Activate Bearer Connection 9. Activate Media Port & Connection SAMSUNG Electronics Co., Ltd. 17
Network Elements Requirements for IMS QoS E2E QoS signaling (SIP/SDP) Call admission control Authorize resources Policy Decision Decision-making Policy repository & PEP Interface QoS base SDP inspection E2E QoS signaling (SIP/SDP) Application to IP QoS mapping MGW control for QoS IMS(PDF) SIP MGCF HSS QoS Profile App. QoS mapping RL QoS scheduling Multi-RLP features GAUP for QoS configuration MEGACO COPS (or Diameter) IP Multimedia Domain MGW ToS set to media packet PSTN UE Access Node Backhaul Network IP Edge Data Core Network Border Router Internet Interior QoS (PHB) FL QoS RF scheduling Admission control for RF resource Congestion & flow control QoS monitoring AAA interface for user s QoS profile Edge node DiffServ QoS link QoS PEP function for SBLP QoS Edge node DiffServ QoS [Classification, Conditioning (Re- Marking, Shaping, Dropping), PHB] PEP function for SBLP QoS SAMSUNG Electronics Co., Ltd. 18
IMS Charging Architecture Online, Offline Charging Architecture Functional Entities Offline Charging Physical Mapping Model
Online/Offline Charging Architecture CN Domain Service elements Subsystem 3GPP network C T F Offline Charging Architecture C C Rf Ga Bx Billing D G Domain F F CTF Charging Trigger Function CDF Charging Data Function CGF Charging Gateway Function BD Billing Domain OCF Online Charging Function ABMF Account Balance Management Function RF Rating Function CN Domain Service elements Subsystem 3GPP network C T F Ro CAP Online Charging Architecture O C F OCS SAMSUNG Electronics Co., Ltd. 20 Rc Re ABMF RF
Functional Entities Charging Trigger Function (CTF) This functional entity generates charging events based on the observation of network resource usage. Charging Data Function (CDF) This functional entity receives charging events from the Charging Trigger Function via the Rf It uses the information contained in the charging events to construct CDRs. Charging Gateway Function (CGF) The CGF acts as a gateway between the 3GPP network and the Billing Domain It receives CDRS from CDR, and performs CDR pre-processing (e.g. validation, consolidation and (re-) formatting of CDRS) and stores CDRs persistently. SAMSUNG Electronics Co., Ltd. 21
Offline Charging Physical Mapping Model Case 1 - CDF and CGF integrated in the NE NE CDF/CGF Bx BD Case 2 - CDF integrated in the NE CGF in a separate physical element NE CDF Ga CGF Bx BD Case 3 - CDF and CGF in two separate physical elements NE Rf CDF Ga CGF Bx BD Case 4 - CDF and CGF in same physical element CCF NE Rf Bx CDF/CGF BD SAMSUNG Electronics Co., Ltd. 22
IMS evolution (3GPP release 7) PCC (Policy Control and Charging) FBI (Fixed Broadband access to IMS) CSI (Combining CS bearers with IMS) VCC (Voice Call Continuity) Service ID
What is PCC? SBLP (Service Based Local Policy) A policy decision point authorizes the QoS for flows and a policy enforcement point enforces the QoS policy and accordingly accepts or rejects the bearer setup. FBC (Flow Based Charging) Apply charging rules on per flow basis. The TPF (Traffic Plain Function) requests the charging rules for flows from the CRF (Charging Rule Function), which gets the flows information from the AF. Merge of SBLP and FBC PCC (FBC as basis) Objective: Complete harmonization and merger of the policy control and flow based charging architecture and procedures Support for end-user subscription differentiation and general policy control aspects to the policy- and charging control Binding bearers to services. Fulfilling the policy and charging control requirements for all different IP access networks. SAMSUNG Electronics Co., Ltd. 24
PCC architecture (PCC) Subscription Profile Repository (SPR) AF Rx Online Charging System (OCS) Sp Policy and Charging Rules Function (PCRF) CAMEL SCP Service Data Flow Based Credit Control Gx Gy PCEF Gz GW Offline Charging System (OFCS) SAMSUNG Electronics Co., Ltd. 25
Reference Points (PCC) Rx reference point It enables transport of application level session information from AF to PCRF IP filter information to identify the service data flow for policy control and/or differentiated charging, Media/application bandwidth requirements for QoS control. Gx reference point It enables a PCRF to have dynamic control over the PCC behaviour at a PCEF Sp reference point It allows the PCRF to request subscription information related to the IP- CAN transport level policies from the SPR based on a subscriber ID and possible further IP-CAN session attributes Gy reference point It allows online credit control for service data flow based charging Gz reference point It enables transport of service data flow based offline charging information SAMSUNG Electronics Co., Ltd. 26
Functional Entities (PCC) Policy and Charging Rules Function (PCRF) The PCRF encompasses policy control decision and flow based charging control functionalities. The PCRF provides network control regarding the service data flow detection, gating, QoS and flow based charging (except credit management) towards the PCEF. Policy and Charging Enforcement Function (PCEF) This functional entity is located at the Gateway (e.g. GGSN in the GPRS case, and PDG in the WLAN case). It provides service data flow detection, user plane traffic handling, QoS handling, and service data flow measurement as well as online and offline charging interactions. Subscription Profile Repository (SPR) The SPR logical entity contains all subscriber/subscription related information needed for subscription-based policies and IP-CAN bearer level charging rules by the PCRF. Service Data Flow Based Credit Control Function This functional entity performs online credit control functions. SAMSUNG Electronics Co., Ltd. 27
IMS evolution (3GPP release 7) PCC (Policy Control and Charging) FBI (Fixed Broadband access to IMS) CSI (Combining CS bearers with IMS) VCC (Voice Call Continuity) Service ID
Fixed Broadband access to IMS (FBI) IMS objective Commonality: Economies of scale (in terms of hardware, software and application development) can be improved by increasing the commonality of IMS for different IP-connectivity networks (including specifically the 3GPP, 3GPP2 and W-LAN IPconnectivity networks) Interoperability: A user on one (e.g., the 3GPP) IMS system needs to be able to phone (i.e., make a multimedia call with a speech component) users on another (e.g. 3GPP2) IMS system Global roaming: A user with an IMS service subscription should be able to gain access to his IMS services from any access network that is compatible with his terminal SAMSUNG Electronics Co., Ltd. 29
IMS in the NGN architecture (FBI) TISPAN Applications Customer Premises Equipment Service Layer Network Attachment Subsystem User profiles Resource and Admission Cont rol Subsyst em Other subsyst ems Core IMS Core IMS PSTN/ISDN Em ul at i on Emulation subsyst em Other net works Transport Layer Transfer Functions The Core IMS service subsystem is a subset of the IMS functions defined by 3GPP multiple service subsystem domains may be connected to a single NGN transport domain and vice versa logically Core IMS and PSTN/ISDN Emulation are different subsystems; this does not preclude implementation in one physical system SAMSUNG Electronics Co., Ltd. 30
Core IMS (FBI) Core IMS e2 P-CSCF NASS CLF PDF RACS NGN Transport Gq Gq 3GPP IP-CAN PDF Core IMS is limited to session-, trunking media gateway- and media processing control and breakout network and gateway selection Service based QoS requests are forwarded to a policy decision in the Resource and Admission control subsystem in the transport layer SAMSUNG Electronics Co., Ltd. 31
IMS evolution (3GPP release 7) PCC (Policy Control and Charging) FBI (Fixed Broadband access to IMS) CSI (Combining CS bearers with IMS) VCC (Voice Call Continuity) Service ID
CSI: Combination of CS and IMS services Parallel operation of a CS service and an IMS session between the same two users CSI UE: IMS capable but prefer using CS domain for voice calls Phase1 and phase2 Phase1: end-to-end scenario Phase2: TBD SAMSUNG Electronics Co., Ltd. 33
CSI phase1 High level architecture CS Uu/Um Uu/Um CS Core Nc Nb CS Core Uu/Um Uu/Um CS UE xran ISC AS ISC AS xran UE IMS Client PS Core Gm IMS Core Mw Mb IMS Core Gm PS Core IMS Client Originating session side Terminating session side SAMSUNG Electronics Co., Ltd. 34
CSI phase1 IMS session set up without media requiring resource reservation UE-A CS Domain (A) IMS Core (A) IMS Core (B) CS Domain (B) UE-B 1. CS Call Setup 2. IMS Capability exchange (see Note) User A triggers an IMS service from a set of illuminated choices 3.INVITE 4. INVITE 5. INVITE 6. User B accepts the service 7. 200 OK 8. 200 OK 9. 200 OK 10.ACK 11. ACK 12. ACK 13. Media session established SAMSUNG Electronics Co., Ltd. 35
CSI phase1 User adds a CS call to an ongoing IMS session UE-A CS Domain (A) IMS Core (A) IMS Core (B) CS Domain (B) UE-B 1. INVITE (Requested Services, Current CSI Capabilities, MSISDN) 6. 200 OK (Requested Services (subset), Current CSI Capabilities (subset), MSISDN) 2. INVITE (Requested Services, Current CSI Capabilities, MSISDN) 5. 200 OK (Requested Services (subset), Current CSI Capabilities (subset), MSISDN) 3. INVITE (Requested Services, Current CSI Capabilities, MSISDN) 4. 200 OK (Requested Services (subset), Current CSI Capabilities (subset), MSISDN) 7. Call flow continues as per standard IMS flow 8. SETUP 9. IAM 10. SETUP 11. ALERTING UE recognises calling party number as negotiated in SIP session setup 12. ACM 13. ALERTING 14. ANSWER. 15. ANM 16. ANSWER SAMSUNG Electronics Co., Ltd. 36
CSI phase2 Issues To handle terminating real-time sessions and calls taking into account different domains (CS, IMS) and different UE capabilities (CSI, IMS VoIP, etc...). SAMSUNG Electronics Co., Ltd. 37
IMS evolution (3GPP release 7) PCC (Policy Control and Charging) FBI (Fixed Broadband access to IMS) CSI (Combining CS bearers with IMS) VCC (Voice Call Continuity) Service ID
VCC: Voice call continuity between CS and IMS Objective To offer the real-time voice call seamlessly between the CS Domain and the IMS Domain Ability for the UE to detect and automatically select the appropriate Access Network Mechanism for selecting how to route the terminating voice calls to the UE Voice call continuity when the user is moving between CS Domain and IMS Domain SAMSUNG Electronics Co., Ltd. 39
VCC Architecture P-CSCF Mw S-CSCF Access to IMS over IP-CAN Cx ISC VCC procedure UE/MS HSS R1 Routing Determination CCCF/ NeDS Access to CS domain over 3GPP access D Registration of call via MAP C i/f R2 E C NeDS Invoking Call continuity CS to IMS MSC GMSC SAMSUNG Electronics Co., Ltd. 40
Voice Call Continuity (VCC) Call Continuity Control Function (CCCF) function for call continuity between the GSM/UMTS Circuit Switch domain and IMS domain using an IP Connectivity Access Network Functionality Reception and processing of call continuity requests caused by radio related events, e.g. availability or loss of radio coverage Establishment, catenation and release of call legs needed to transfer a voice call from CS domain to IMS domain, or visa versa Network Domain Selection (NeDS) Function to control point for selecting which domain to use for terminating a call. Functionality The NeDS function is aware of whether the terminal is registered on IMS from a device that is Multimedia telephony (with IMS voice) capable, and on an access that is capable to support IMS voice; The NeDS function is aware of whether the terminal is attached to the CS domain. The NeDS function is aware of or can obtain the ongoing voice call in the IMS and the CS domain. SAMSUNG Electronics Co., Ltd. 41
IMS evolution (3GPP release 7) PCC (Policy Control and Charging) FBI (Fixed Broadband access to IMS) CSI (Combining CS bearers with IMS) VCC (Voice Call Continuity) Service ID
Service ID: IMS Communication Service Identifier Objective (TR23.816) : Identify the application server on the ISC interface Input into media authorisation policy Service authorisation Priority in the case of overload situations Interworking identification Routing to the correct terminating device Input into charging and accounting Identification of the application to invoke in the terminating terminal SAMSUNG Electronics Co., Ltd. 43
Service ID High Level Overview Operator A Operator B HSS AS AS HSS PDF CSCFs CSCFs PDF MRF (C/P) MGCF/ MGW MRF (C/P) MGCF/ MGW Identify the policy to apply Authorization to use the service (ability to receive the service, and also the ability to receive the requests for the service) Identify the application server to link in. Identify the need for interworking (e.g. IMS async mess MMS) Identify the correct terminating device to contact Identify the correct application within the device to link in Need of identifying IMS communication services SAMSUNG Electronics Co., Ltd. 44