ITU-R WP8F activitiesold.hsn.or.kr/workshop/hsn2006/document/2.23.Thu/4-2.pdfPDF’s QoS decision and IP Edge node’s (e.g., GGSN, PDSN, ACR) resources PDF’s QoS decision based

세션 제어 프로토콜 기술

2006. 2. 23

삼성전자

© SAMSUNG Electronics Co., Ltd. 1

목차

Overview

IMS features

IMS Subscription ID & Service Trigger

IMS QoS

IMS Charging Architecture

IMS evolution

Overview

FMC IsIntroduction of IMS3GPP IMS Reference Model


FMC Is

사업자의 Resource(통신망/서비스/장비/인력 등)를

상호 보완적으로 Converge하여

사업자 및 고객에게 새로운 가치를 창출

Device

Convergence

All IP

Multi-Band

Wide-Band

N/W & Service

Convergence

IMS Core N/W

Standard Service

(OMA, IETF, 3GPP)

Open Interface

(SIP,Parlay)

Commercial

Convergence

Marketing

Management

Bundle Service

Charging

Device

Convergence

Multi-Band Device

Multi-Mode Device

Multi-Media Device

(TPS+Broadcast)

Commercial

Convergence

Marketing & Channel

Biz Management

Bundle Service

Single Bill


Introduction of IMS

IMS introduced in UMTS Rel5, and further enhanced in Rel6:

IP Multimedia domain for call control based on SIP3GPP specifies features to fullfill operator requirements, e.g.:

QoS controlChargingSecuritySubscription profilesInterworking with other networks (CS/PSTN)

IMS provides building blocks allowing faster integration and deployment of IP multimedia services


Mw

Mw

Go Gm

Dx Cx

ISC

ISCOSA-API

ISC

Mr

MgMn

Mp

MjMk Mi

Mb

Mb

PSTN

Mb

MbMb

Mm CAP

IMSMGW

MRFP

MGCF OSASCS

OSAASBGCF CSCF IM

SSF

MRFC ProxyCSCF SLF HSS

UEGGSN

Mb

AS

IP Multimedia Networks Legacy Signaling NetworksPSTN

PSTN

CSCF

• AS : Application Server

• BGCF : Breakout Gateway Control Function

• CAP : CAMEL Application Part

• GGSN : Gateway GPRS Support Node

• HSS : Home Subscriber Function

• CSCF : Call Session Control Function

• MGCF : Media Gateway Controller Function

• MGW : Media Gateway

• MRFC : Multimedia Resource Function Controller

• MRFP : Multimedia Resource Function Processor

• OSA : Open Services Architecture

• SCS : Service Capability Server

• SLF : Subscription Locator Function

3GPP IMS Reference Model

IMS features(3GPP release 5/6)

IMS in Release-5IMS Phase 2 – Release 6


IP Multimedia Core Network Subsystem (IMS)

IP Multimedia Core Network Subsystem (IMS) became part of 3GPP Rel-5Uses SIP (Session Initiation Protocol) as the protocol for sessionmanagementSIP is standardised by IETF (RFC-3261)Main SIP functionality:

Setup, Modify and Tear down of multi-media SessionsRequest and deliver presence informationInstant messagingWorks 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 URIAssociated to a user for a shorter period of time

IMS in Release-5


IMS Phase 2 – Release 6

Main Work Items for IMS Phase 2:IMS ConferencingIMS MessagingIMS Group ManagementAdditional SIP capabilities (e.g. forking)Interworking with IP networks: IETF SIP and IPV4 networksInterworking between IMS and CS networksLocal Services

Other WIs:Interworking and migration scenario for IPv4 based IMSQoS improvements (Gq)3GPP enablers for services like PoCIMS Commonality and InteroperabilityFlow-Based Charging

IMS Subscription ID & Service Trigger

IMS Subscription & ID Service Triggering Architecture for IMSFilter Criteria (TS 23.218)Service Point Triggers (TS 23.218)


IMS Subscription & ID

IMSSubscription

PublicUser Identity 1



PrivateUser Identity

PrivateUser Identity




ServiceProfile 1

ServiceProfile 2

ServiceProfile 3

ServiceProfile 4

Implicitly

Registered ID Set 1

Implicitly

Registered ID Set 2

Implicitly

Registered ID Set 3


Service Triggering Architecture for IMS

SS--CSCFCSCF

SSPPTT

Application ServerApplication Server

Service LogicService Logic

Service Platform Trigger PointsService Platform Trigger Points

SIP InterfaceSIP Interface

Filter CriteriaFilter CriteriaSIPSIP

iFCiFC sFCsFC SIPSIP

SIPSIP

HSSHSS


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)서비스를 제공 받을 AS로 트리거링 하기위한 조건 등을 정의(HSS로부터 수신)

Subsequent Filter Criteria (sFC)AS를 통한 서비스 수행 중, 서비스 제공에 필요한 dynamic한트리거링 정보를 정의 (AS로부터 수신)

규격에서의 서비스 처리 기본 원칙

S-CSCF는 session control만 수행

iFC를 이용하여 AS로 트리거링을 수행, AS를 통하여 서비스 제공


Service Point Triggers (TS 23.218)Service Point Triggers (SPTs)

Service Point Triggers (SPTs) are those points in the SIP signallingon 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 fieldContent of any header field or Request-URIDirection of the request is with respect to the served user

MO or MT to registered userMT to unregistered user

REGISTER is considered part if the MOThe S-CSCF shall verify if the end user is barred before checking if any trigger applies for that end user

Session description information

IMS QoS

IMS based QoSNetwork 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) resourcesPDF’s QoS decision based on IMS QoS signaling and the operator’s policy rulesSupports maximum bandwidth if resources are available

IMS based QoS DefinitionUE demands required QoS for service

Application level E2E QoS negotiationEnd-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)


IMS based QoS (2/3)Mechanism for E2E QoS authorization

SDP InspectionSDP 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 authorizationP-CSCF generates the service information from SDP and sends it to PDFPDF authorizes the QoS requirements from IMS-Proxy based on operator policy rulesPDF creates and saves SBLP that reflects authorization results.PDF authorizes the QoS requirements from IP Edge nodebased on SBLP


IMS based QoS (3/3)IMS based QoS (3/3)

P-CSCF S-CSCFUE AS

SDP InspectionSDP Inspection

SDPSDP inspection performs based on Local Policy.

SDP inspection performs based on Local Policy or User Subscription

AS checks SDP and request confirmation for the resource reservation at the endpoint.

GGSN

3-1. ServiceInformation

Gq

Go

5. Bearer Authorization request

PDF

UE1

Local Policy

P-CSCF

QoS authorization based on SBLPQoS authorization based on SBLP

4.Second PDP Context Setup Req

6. QoS authorization based on SBLP

7. Bearer Authorization

response8. Second PDP Context Setup Res

9. QoS Commit

SBLP

3-2. QoS authorization,Create SBLP

UE2

1. SDP from UE1

3-4. SDP from UE2

2. QoS negotiation

8. Activate Bearer Connection 9. Activate Media Port & Connection

3-3 Authtoken


Network Elements Requirements for IMS QoS

AccessNodeUE

Backhaul Network

• FL QoS RF scheduling• Admission control for RF resource• Congestion & flow control• QoS monitoring

• App. QoS mapping• RL QoS scheduling • Multi-RLP features• GAUP for QoS configuration

Data Core Network Internet

IP Multimedia Domain

SIP

MEGACO

MGCF

MGW

COPS (or Diameter)

BorderRouter

IMS(PDF)

• 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

IP Edge

• 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

PSTN

• ToS set to media packet

• Interior QoS (PHB)

HSS

• QoS Profile

IMS Charging Architecture

Online, Offline Charging ArchitectureFunctional EntitiesOffline Charging Physical Mapping Model


Online/Offline Charging Architecture

3GPP network

Offline Charging Architecture

CNDomain

Serviceelements

Subsystem

CTF

CDF

CGF

GaRf Bx BillingDomain

3GPP network

Online Charging Architecture

CNDomain

Serviceelements

Subsystem

CTF

RoCAP

OCS

OCF

CTF Charging Trigger FunctionCDF Charging Data FunctionCGF Charging Gateway FunctionBD Billing DomainOCF Online Charging FunctionABMF Account Balance Management FunctionRF Rating Function

RF

ABMFRc

Re


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 RfIt 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 DomainIt receives CDRS from CDR, and performs CDR pre-processing (e.g. validation, consolidation and (re-) formatting of CDRS) and stores CDRs persistently.


Offline Charging Physical Mapping Model

NECDF/CGF

BxBD

NECDF

GaCGF

Bx BD

NE Rf Bx BD

NECDF

Rf CGF Bx BDGa

Case 1 - CDF and CGF integrated in the NE

Case 2 - CDF integrated in the NE CGF in a separate physical element

Case 3 - CDF and CGF in two separate physical elements

Case 4 - CDF and CGF in same physical element

CDF/CGF

CCF

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 proceduresSupport for end-user subscription differentiation and general policy control aspects to the policy- and charging controlBinding bearers to services.Fulfilling the policy and charging control requirements for all different IP access networks.


PCC architecture (PCC)

GW

Online Charging System (OCS)

Service Data Flow Based

Credit Control

Policy and Charging

Rules Function (PCRF)

CAMEL SCP

Gy

Rx

AF

Gz

Gx

Subscription Profile Repository

(SPR)

Sp

Offline Charging System (OFCS)

PCEF


Reference Points (PCC)

Rx reference pointIt 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 pointIt enables a PCRF to have dynamic control over the PCC behaviour at a PCEF

Sp reference pointIt 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 pointIt allows online credit control for service data flow based charging

Gz reference pointIt enables transport of service data flow based offline charginginformation


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 FunctionThis functional entity performs online credit control functions.




Fixed Broadband access to IMS (FBI)

IMS objectiveCommonality:

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 IP-connectivity 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


IMS in the NGN architecture (FBI) – TISPAN

The Core IMS service subsystem is a subset of the IMS functions defined by 3GPPmultiple service subsystem domains may be connected to a single NGN

transport domain and vice versalogically Core IMS and PSTN/ISDN Emulation are different subsystems;

this does not preclude implementation in one physical system

Other netw

orks

Other subsystems

Core IMS

PSTN/ISDN Emulat ionsubsystem

Customer Prem

ises Equipment

Service Layer

Transport Layer

Transfer Funct ions

Resource and Admission Control

Subsystem

Network Attachment Subsystem

Applicat ions

Userprofiles

Core IMSPSTN/ISDNEmulation


Core IMS (FBI)

Core IMS is limited to session-, trunking media gateway- and media processing control and breakout network and gateway selectionService based QoS requests are forwarded to a policy decision in

the Resource and Admission control subsystem in the transport layer

P-CSCF

Core IMS

PDF

3GPP IP-CAN

NGN Transport

PDFRACS

CLFNASS

Gq

Gq’

e2




CSI: Combination of CS and IMS services

Parallel operation of a CS service and an IMS session between the same two usersCSI UE: IMS capable but prefer using CS domain for voice callsPhase1 and phase2

Phase1: end-to-end scenarioPhase2: TBD


CSI phase1

High level architecture

xRAN UE UE

Uu/UmUu/Um

NcNb

Gm

Mb

Mw

Originating session side

Uu/UmUu/Um

Gm

Terminating session side

xRAN

IMSClient

CS

ISC

CS Core CS

IMS Client

ASAS

CS Core

IMS Core

PS Core

ISC ASAS

IMS Core

PS Core


CSI phase1IMS session set up without media requiring resource reservation

CS Domain (A) CS Domain (B) UE-BIMS Core (A)UE-A IMS Core (B)

3.INVITE

5. INVITE

7. 200 OK

8. 200 OK

9. 200 OK

1. CS Call Setup

2. IMS Capability exchange (see Note)

4. INVITE

10.ACK

12. ACK

11. ACK

User A triggers anIMS service from a setof illuminated choices

6. User B acceptsthe service

13. Media session established


CSI phase1User adds a CS call to an ongoing IMS session

CS Domain (A) CS Domain (B) UE-BIMS Core (A)UE-A IMS Core (B)

1. INVITE(Requested Services, Current CSI

Capabilities, MSISDN) 3. INVITE(Requested Services, Current CSI Capabilities, MSISDN)

4. 200 OK(Requested Services (subset),

Current CSI Capabilities (subset),MSISDN)


Current CSI Capabilities (subset),MSISDN)


Current CSI Capabilities (subset), MSISDN)

7. Call flow continues as per standard IMS flow

2. INVITE(Requested Services,

Current CSI Capabilities,MSISDN)

8. SETUP

10. SETUP

9. IAM

11. ALERTING

12. ACM

13. ALERTING 14. ANSWER.15. ANM

16. ANSWER

UE recognises calling party number as negotiated in SIP session setup


CSI phase2

IssuesTo handle terminating real-time sessions and calls taking into account different domains (CS, IMS) and different UE capabilities (CSI, IMS VoIP, etc...).




VCC: Voice call continuity between CS and IMS

ObjectiveTo 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


VCC Architecture

S-CSCF

CCCF/NeDS

GMSC

HSS

P-CSCF

MSC

UE/MS

Mw

CxISC

D

E C

Access to CS domain over 3GPP access

Access to IMS over IP-CAN

NeDS Invoking

Routing Determination

of call via MAP C i/f

VCC procedure

Call continuity CS to IMS

Registration R2

R1


Voice Call Continuity (VCC)

Call Continuity Control Function (CCCF)function for call continuity between the GSM/UMTS Circuit Switchdomain and IMS domain using an IP Connectivity Access NetworkFunctionality

Reception and processing of call continuity requests caused by radio related events, e.g. availability or loss of radio coverageEstablishment, 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.




Service ID: IMS Communication Service Identifier

Objective (TR23.816) : Identify the application server on the ISC interfaceInput into media authorisation policyService authorisationPriority in the case of overload situationsInterworking identificationRouting to the correct terminating deviceInput into charging and accountingIdentification of the application to invoke in the terminating terminal


Service ID High Level OverviewOperator A Operator B

HSS

CSCFs

AS

PDFMRF (C/P)

MGCF/MGW

HSSAS

CSCFs

MRF (C/P)

MGCF/MGW

PDF

• 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

Documents

ITU-R WP8F activitiesold.hsn.or.kr/workshop/hsn2006/document/2.23.Thu/4-2.pdfPDF’s QoS decision and IP Edge node’s (e.g., GGSN, PDSN, ACR) resources PDF’s QoS decision based