Introducing IMS Standardization

WANG XinLong CAICT Contents

• IMS Summary

• International IMS Standards

• IMS Standards in China

3GPP Release 99 Network architecture

Circuit Switched (CS) domain MAP MSC- A G-MSC PSTN/ISDN VLR PSTN/ISDN BTS BSC

Gb CAP MAP GSM Base Station System other SCP HLR SMS SC PLMN

CAP MAP Iu CS Gp NodeB RNC GPRS backbone Internet SGSN GGSN Iu PS IP transport Intranet UMTS Terrestrial Gi Gn Packet Switched (PS) domain Radio Access Network Interworked Core Network Network 3GPP Release 4 Network architecture

Circuit Switched (CS) domain

SCP HLR

BTS BSC CAP MAP A G-MSC MSC GSM Base Station System server server BICC other H.248 / H.248 / PLMN MEGACO MEGACO based based

NodeB RNC I IP or ATM u CS CS-MGW MGW PSTN/ISDN transport UTRAN

Access Network Interworked Core Network Network 3GPP Release 5 Network architecture

Circuit Switched (CS) domain

services & services & BTS BSC HLR HSS applications applications

GSM BSS Internet Gb/Iu PS MAP CSCF SIP

SIP MGCF

IP transport H.248

Iu PS MGW PSTN/ISDN NodeB RNC -SGSN GGSN Gi

IP access with mobility UTRAN Packet Switched (PS) domain Interworked Access Network Core Network Network 3GPP Release 5 - Packet switched domain

IN/CAMEL, OSA/Parlay, SIP applications Application Platform

Legacy PLMN IP Multimedia Subsystem Signaling CSCF Networks External IP MGCF Networks Data Packet Switched bases HSS Web server Domain 3G- GGSN IP MGW 3G- TDM SGSN POTS/ISDN

UTRAN Web / Email SIP Communication (IMS) Internet Access without IMS Multimedia phone Mobility Network Evolution

2G 2.5G 3G- R99 3G - R4 3G – R5 2.75G

MSC Server MSC Server GSM MSC MSC UMTS MSC CS CS MGW MGW + CS CS CS PS + GPRS + + EDGE PS PS PS

GGSN SGSN GGSN GGSN GGSN SGSN SGSN SGSN

IMS Voice 3G Packet IP Multimedia Subsystem （IMS）

The IP Multimedia Subsystem (IMS) • provides a standardised multimedia solution for 3G networks on top of the IP bearer provided by GPRS • includes functionality for security, charging, , and • is regarded as the generic service enabler for future IP multimedia applications in 3GPP networks - Examples: Presence and Messaging Services will be standardised via IMS • is based on IETF Protocols - SIP and SIP extensions - , COPS, … IMS

Web Portal Application Layer Application Servers IMS is: . Home control service infrastructure . A VoIP Telephony and Multimedia Services Architecture Session Session Centralized Control . Defined with Open Standard Control Databases Layer Interfaces -> 3GPP and 3GPP2 CSCF HSS . Based on IETF Protocols (SIP, Diameter, RTP…) Access Network . Applicable for Both Wireless and Media Server Wireline Networks . A Solution for Service Transparency Media Control & . Capable of Interworking with Gateways PSTN/PLMN and Legacy IN Based Services Media and End Point Other Layer Networks IMS: Key Principles

• SIP as the single , Call Control“ Protocol for IP Multimedia Services • Use IPv6 - all IMS Network Entities including the mobile terminal use IPv6 • Access Independence - the IMS is designed independent of the underlying IP connectivity network - specifications re-used by 3GPP2 for CDMA2000 systems - access via WLAN will be defined • Allow Binding between SIP Dialogue and the GPRS Media Session via Go interface - in particular for QoS and Charging IMS: NetworkIMS in 3GPP entity Release and 5 protocol– 网络实体和协议

SGW HTTP Others Applications Operator 1 Operator 2 … … Multimedia and BGCF Diameter Sh CSCF Services HSS IP Mw Mk HLR SIP SIP Networks Si SIP

ISC Mm SIP TCP UDP

BGCF Diameter

CAP IM-SSF

SIP SLF Mi

OSA-SCS Cx Dx OSA SIP Mj CS Domain

Diameter

Sc SIP -or-

SIP CSCF MGCF SGW ISUP AS PDF Mg PSTN Mr H248 -or-

SIP Mn MAP Mp MRF-C MRF-P Legacy SCP COPS MGW H248 Gr Gc Go -or- Gm CAP SIP External

GGSN TCP/IP/UDP/RTP/… UE Gn GERAN Alternative MT TE SGSN Access Networks R Uu UTRAN Iu PS Domain IMS: Network entity

• CSCF (Call Session Control Function) • HSS (Home Subscriber Server) • PDF (Policy Decision Function) Additionally: • SLF (Subscription Locator Function) - QoS Entities - Charging Entities • MRF (Multimedia Resource Function) - Security Entities • BGCF (Breakout Gateway Control Function) - Presence Service Entities • MGCF ( Control Function) - Location Service Entities • MGW (Media Gateway) - Push Service Entities • SGW (Signalling Gateway) - OAM and NM Entities • AS (Application Server) - Firewalls, NAT, IPv4/v6, … • IM-SSF (IP Multimedia Service Switching Function) - DNS, DHCP, … • OSA-SCS (Service Capability Server) P-CSCF (Proxy CSCF)

First contact point of an operator‘s network (within IMS CN subsystem)

• Forwarding of SIP messages between UE and CN

• Generation of charging records

• Translation of IDs other than SIP URIs into SIP URIs (e.g. E.164 numbers)

• Authorisation of bearer resources and QoS management I-CSCF (Interrogating CSCF)

First contact point of an operator‘s network (for other operators)

• Forwarding of SIP messages (proxy functionality)

• Assignment of a S-CSCF

• Generation of charging records

• Hiding of internal network configuration/capacity/topology S-CSCF (Serving CSCF)

Performs session control and service triggering

• Acts as a registrar

• May behave as a Proxy Server, i.e. it accepts requests and services or forwards them on.

• May behave as a User Agent, i.e. it may terminate and independently generate SIP transactions.

• Interaction with service platform(s)

• Generation of charging records

• Authentication HSS

Database for subscriber related information • User Profile • User Identification, Numbering and addressing information (SIP, Mail, E.164, Labels, IMSI, ...) • User authentication support • Call control support • Access authentication support • Service authorization support • Service provisioning support BGCF (Breakout Gateway Control Function)

• Selects the network in which PSTN breakout is to occur

- Forwards the session to a MGCF (selected by the BGCF) in the same network

- Forwards the session to an other BGCF (or MGCF) in a foreign network

• Receives request from S-CSCF to select appropriate PSTN break out point for the session

• Generation of charging records MRF

The MRF is split into Multimedia Resource Function Controller (MRFC) and Multimedia Resource Function Processor(MRFP). It is mainly for conferencing and announcements.

• MRFC-- Control the media stream resources in the MRFP

• MRFP-- Provide resources to be controlled by the MRFC and Media stream processing (e.g. audio transcoding, media analysis) IMS: Register and session setup

Home Network of UE A Home Network of UE B

HSS-A User Profile I-CSCF-B HSS-B 4 5 3 CSCF = Call Session Control Function I-CSCF-A S-CSCF-A S-CSCF-B (I = Interrogating, P= Proxy, S = Serving)

UE A UE B 6 HSS = Home Subscriber Server

UE =

REGISTER

INVITE Call Control / Dialog / Control Call 1 2 7

P-CSCF-A Media Session P-CSCF-B

Network visited by UE A Network visited by UE B Contents

• IMS Summary

• International IMS Standards

• IMS Standards in China

3GPP organization structureGPP 组织结构以及与IMS相关的工作组

Stage 3 (Protocols):

SIP IMS Stage 1

CAMEL Interworking IMS Arch.(Stage 2)

COPS, Interworking IMS Security ISIM

DIAMETER

OSA Interworking IMS Charging IMS Release 5 specification(一)

• IMS Stage 1 - 3GPP TS 22.228: IP multimedia subsystem; Stage 1 • IMS Stage-2/3 - 3GPP TS 23.228: IP Multimedia Subsystem (IMS); Stage 2

- 3GPP TS 24.229: IP Multimedia Call Control Protocol based on SIP and SDP; Stage 3

- 3GPP TS 29.228: IP Multimedia (IM) Subsystem Cx Interface; Signalling flows and message contents

- 3GPP TS 29.229: Cx Interface based on the Diameter protocol; Protocol details

- Others are TS 23.218, 29.229, 29.328, 29.329

IMS Release 5 specification(二)

• 3GPP requirements and architecture - 3GPP TS 23.002, 23.003, 23.008, 23.221, 27.060

• 3GPP QoS management and Service Based Local Policy for IMS - 3GPP TS 23.207, 29.207, 29.208

• 3GPP Charging and Billing for IMS - 3GPP TS 32.200, 32.225

• 3GPP Security for IMS - 3GPP TS 33.203, 33.210

• Signalling Flows for IMS - 3GPP TS 24.228: Signalling flows for the IP multimedia call control based on SIP and SDP; Stage 3

• CAMEL Support for IMS - 3GPP TS 23.278, 29.278 IMS Release 6 specification

• Interoperability and Commonality – support for use of the IMS core by other access technologies

• IMS Local Services – support for access to services in visited network

• IMS to PS Interworking – support for interworking with IP endpoints including IPv4/IPv6 interworking…

• IMS to CS Interworking – support for SIP/ISUP interworking and CS roaming scenarios

• IMS Conferencing – support for IMS based conference provision and control IMS Release 6 specification

• SIP Capabilities Enhancements – support for enhanced SIP capabilities such as forking

• QoS and Service Based Local Policy Enhancements – support for Gq interface and non-IMS applications

• WLAN Interworking – support for WLAN

• Presence Capability – support for presence

• Generic User Profile – support for user data management 3GPP IMS Recommendations

. 3GPP TS 23.002: Technical Specification Group Services and Systems Aspects; Network Architecture

 An overview of mobility network, including CS, PS and IMS  Brief introduction to mobility network architecture & configuration  Section 4.a.7 and 5.5 defines IMS . 3GPP TS 22.228: Service requirements for the (IP) multimedia core network subsystem (IMS); Stage 1

 Defines service requirements from users’ and operators’ perspective for the support of IP multimedia applications.  It defines the support of IP multimedia applications, not the applications themselves . 3GPP TS 23.228: IP Multimedia Subsystem (IMS); Stage 2

 Overall technical description of IMS. (more detailed than 22.228)  Divided into concept and procedure sections.  Concept section gives definition of services, UE naming, etc.  Procedure section gives an high-level procedures needed to setup a session. 3GPP IMS Recommendations (cont.)

. 3GPP TS 23.218: IP Multimedia (IM) session handling; IM call model; Stage 2

 Functional requirement of CSCF  Functional requirement of HSS  Functional requirement of MRFC  IMS Session handling for Application servers . 3GPP TS 24.228: Signaling flows for the IP multimedia call control based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 . 3GPP TS 24.229: Internet Protocol (IP) multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 Overall technical description of IMS.

27 | IMS Overview | November 2007 Major SIP related RFCs in IMS

. RFC 3261 – (base) SIP protocol . RFC 3262 – Reliability of provisional responses in SIP . RFC 3265 – SIP specific event notification . RFC 3312 – Integration of resource management and SIP

. RFC 3313 – Private SIP extensions for media authorization .RFC 3608 – SIP extension header field for service route . RFC 3323 – Privacy mechanism for SIP discovery . RFC 3325 – Private SIP extensions for network asserted identity .RFC 3680 – SIP event package for registrations . RFC 3327 – SIP extension header field for registering contacts .RFC 3311 – SIP UPDATE method . RFC 3428 – SIP extension for instant messaging .RFC 3515 – SIP REFER method . RFC 3455 – Private header extensions to SIP for 3GPP .RFC 2976 – SIP INFO method .RFC 3326 – Reason Header for SIP How IMS uses SIP

IMS defines extensions to headers and parameters to address specific needs . auth-param: Allows passing of Integrity Key and Cipher Key during the registration process . tokenized-by: Allows carrying of encrypt/decrypt strings within the SIP headers to implement the I-CSCF THIG function. . P-Asserted-Identity: Allows the network (e.g. P-CSCF) to assert a public user identity for identifying the calling user. . P-Called-Party-ID: Allows the terminating UE to learn dialed public user identity that triggered the call. . P-Access-Network-Info: Allows the UE to provide information related to the access network it is using (e.g. cell ID). . P-Visited-Network-ID: Allows the home network to discover, via registration, the identities of other networks utilized by the user. . P-Associated-URI: Allows the home network (e.g. S-CSCF) to return a set of URIs associated with the public user identity under registration. . P-Charging-Function-Addresses: Allows for distributing addresses of charging function entities. . P-Charging-Vector: Allows for sharing of charging correlation information (e.g. ICID).

Contents

• IMS Summary

• International IMS Standards

• IMS Standards in China

CCSA TC5 (China Communications Standards Association) IMS Standardization

. Technical Requirements for IMS system device

. Test Method for IMS system device

. Technical Requirements for IMS system – Cx/Dx/Sh Interface

. Test Method for IMS system – Cx/Dx/Sh Interface

. Technical Requirements for IMS system – Mg/Mi/Mj/Mk/Mw/Gm Interface

. Test Method for IMS system – Mg/Mi/Mj/Mk/Mw/Gm Interface

. Technical Requirements for IMS system – ISC/Ma Interface

. Test Method for IMS system – ISC/Ma Interface

CCSA TC5 (China Communications Standards Association) IMS Standardization (cont.)

. General Technical Requirements of Voice over LTE（VoLTE

. Technical requirements for network equipments of Voice over LTE(VoLTE)

. Test Method for network equipments of Voice over LTE (VoLTE)

. Technical Specification for User Equipment of voice over LTE（VoLTE）

. Test Method for User Equipment of voice over LTE（VoLTE）

. Part I: Function and Performance Test

. Test Method for User Equipment of voice over LTE（VoLTE）Part2:Conformance Test Trainer: Xinlong Wang E-mail: [email protected] Department: The Institute of Communication Standards Research Photo：86-10-62300184

Thank you for your attention

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