slide title in capitals 50 pt slide subtitle 32 pt ims: an architecture for convergent next...

Slide titleIn CAPITALS

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IMS: An Architecture for Convergent Next Generation Multimedia Services. Research and

Standardisation Challenges

Dr. Sorin [email protected]

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Bullets level 2-520 pt

IMS Convergent Multimedia Services Sorin Georgescu2

Agenda

IMS Architecture Overview Standardisation Status The Service Layer View IMS and SOA Research and



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Next Generation Networks Evolution Drivers

Societal and Business trends

• Internet is becoming a major enabler of communications

• Consumers are embracing computing, mobile and digital technology in their everyday life

• Evolution of Business models require increased levels of personal mobility

Societal and Business trends

• Internet is becoming a major enabler of communications

• Consumers are embracing computing, mobile and digital technology in their everyday life

• Evolution of Business models require increased levels of personal mobility

Access Technology Enhancements

• HSPA (High Speed Packet Access) – evolved WCDMA

• OFDMA (Orthogonal Frequency Division Multiple Access) – 3GPP LTE, WiMAX, MBWA, ADSL/VDSL, DVB-T/H etc.

• Spatial Processing – multi-antennas Base Stations supporting advanced spatial processing

Access Technology Enhancements

• HSPA (High Speed Packet Access) – evolved WCDMA

• OFDMA (Orthogonal Frequency Division Multiple Access) – 3GPP LTE, WiMAX, MBWA, ADSL/VDSL, DVB-T/H etc.

• Spatial Processing – multi-antennas Base Stations supporting advanced spatial processing

Convergence

• Converged devices (Mobile, WLAN, Internet etc.) Connectivity

• Converged services Ease of use

• Converged networks Reliability, Security, Reduced OPEX/CAPEX

• Converged business models Increased margins, Avoidance of twin pitfalls risk

Convergence

• Converged devices (Mobile, WLAN, Internet etc.) Connectivity

• Converged services Ease of use

• Converged networks Reliability, Security, Reduced OPEX/CAPEX

• Converged business models Increased margins, Avoidance of twin pitfalls risk


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The Evolution to IMS Multimedia Applications

Non-Interactive Multimedia

Image

SMSMMS

Presence

Activephonebook

Push-To-Talk

Text

Voice

Voice

Sharing

Video

Person-to-Person dominates traffic growth

Movies

Photos

Internet

Text/Pictures

SMS/MMS

HTTP

Streaming

Download

VideoMusic

Ring tonePerson-to-Content known usability patterns

Interactive Multimedia


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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


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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.

• Since release 6, interworking with WLAN is supported.

If IMS is not used:

Multimedia communication at best effort

Service orchestration can be complex

Service roaming can be difficult to implement

Provisioning and charging are service specific

Compliance with LI requirements can be an issue

If IMS is not used:

Multimedia communication at best effort

Service orchestration can be complex

Service roaming can be difficult to implement

Provisioning and charging are service specific

Compliance with LI requirements can be an issue


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IMS/TISPAN Architecture

IMS-MGW

UEIPv6 PDN

(IPv6 Network)

MGCF

PDF

I-CSCFS-CSCF

BGCF

MRFC

MRFP

MRF

BB(IPv4/IPv6)

P-CSCF

SGW

OSA SCSIM SSF

SIP AS

AS

RAN

BG

IMS Session SignallingIMS User Plane Data

HSS

‘IMS Data’ SLF

ALG

TrGW

IMS GW

IPv4 PDN(IPv4 Network)

PEF

CSCF

HLR/AuC (‘CS/PS’)

3GPP R5

WLANPDGUE WLAN

WAG

3GPP R6GGSN

SGSN

CS Networks(PSTN, CS PLMN)BASUE DSLAM

3GPP R7 / TISPAN R1

SPDF/ A-RACFNASS

Application(SIP AS,OSA AS,

CAMEL SE)


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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

• 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

• HSS (Home Subscriber Server):- IMS subscriber records and service profile- IMS authentication data

• 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


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Functional Overview (2)• SIP AS (Application Server):

- Hosts IMS native applications

• IM SSF (IP Multimedia Switching Service Function):

- Provides interworking with CAMEL, ANSI-41, 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

• MGCF (Media Gateway Control Function):- Controls media channels in IMS MGW- Performs conversion between ISUP/TCAP and IMS call control protocols

• IMS MGW (IMS Media Gateway):- Terminates bearer channels from CS networks and PS media streams- Owns/handles resources (echo cancellers, codes, etc.)

• SGW (Signaling Gateway):- Performs conversion at transport level (SCCP, SCTP)

• SBC (Session Border Controller):

• PDF/SPDF (Policy Decision Function / Serving Policy Decision Function):

• A-RACF (Access - Resource and Admission Control Function):

• NASS (Network Attachment Subsystem):

• DSLAM (Digital Subscriber Line Access Multiplexer):


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IMS Service Routing – the IFCs

P-CSCF

Vis

ited

A

P-CSCF Vis

ited

B

S-CSCF

IMS ASHSS

S-CSCF

IMS ASHSS

I-CSCF

12

3

4

Hom

e A

Hom

e B

5

6

7

8

9

10

11

• 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.

• 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.

IMS Service Routing = Service Profile based Routing


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Service/application identification – ICSI/IARI

ICSI1 ICSI2

IARI1 IARI2IARI2

Appl 1 Appl 2

CS 1 CS2

SIP Stack

ICSI = IMS Communication Service ID

IARI = IMS Application Reference ID

CS = Communication Service

• 3GPP TS 23.228 R7 introduced the ICSI/IARI identifiers as a mechanism for UEs to provide a hint to the network on the AS’ they wish to be linked-in the signalling path.

• The introduction of ICSI/IARI in 3GPP aims to address to a certain extent the limitations due to the use of the Service Profile routing paradigm. The ICSI/IARI are used as parameters in the IFC, therefore the AS selection process becomes more dynamic.

• 3GPP TS 23.228 R7 introduced the ICSI/IARI identifiers as a mechanism for UEs to provide a hint to the network on the AS’ they wish to be linked-in the signalling path.

• The introduction of ICSI/IARI in 3GPP aims to address to a certain extent the limitations due to the use of the Service Profile routing paradigm. The ICSI/IARI are used as parameters in the IFC, therefore the AS selection process becomes more dynamic.

• The ICSI/IARI provides a mechanism to control rating based on selected pricing model. For example, it is possible to rate differently a Messaging Communication Service when invoked from a Multimedia application then when invoked from a Gaming application.

• The ICSI/IARI provides a mechanism to control rating based on selected pricing model. For example, it is possible to rate differently a Messaging Communication Service when invoked from a Multimedia application then when invoked from a Gaming application.

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.


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Service Convergence in Quadruple Play

Fixed Mobile Convergence

=Converged Service

Architecture

Industry consolidation and

alliances=

Convergence at Service Provider level.

End User experience

=Access to subscribed

services from any device in the bundle

Common service and subscriber management

Common provisioning, mgmt and billing

Setup of the appropriate QoS and resources

Service continuity


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Agenda




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Standardisation fora

Mobile Mobile

IPIP

Residential Residential

Broadband Access to IMS

PoCPoC MessagingMessagingGLMSGLMSMultimediaMultimediaTelephonyTelephony

GSM/WCDMA Access to IMS

PresencePresence CSICSI

WLAN Access to IMS

VCCVCC

PacketCable™

Enterprise Enterprise

WiMAXForumDSL

ForumDOCSIS


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3GPP R7 Reference Model

IMS

TE MT UTRAN

SMS-SCEIRTE MT

BillingSystem*

R UmGERAN

WAG

Uu

HLR/AuC* HSS*

R

C

Wn Wp

Wu

WLANUE Ww

Intranet/

InternetWa

Wm

Wf

Iu

Gn

Gb, IuGf Gr

Gd

Ga

GiGn/Gp

Gc

SMS-GMSCSMS-IWMSC

WiOCS*

SGSN

SGSN

Note: * Elements duplicated for picture layout purposes only, they belong to the same logical entity in the architecture baseline.

** is a reference point currently missingTraffic and signallingSignalling

HLR/AuC*

3GPP AAAProxy

GaGy

CDF

CGF*

3GPP AAAServer

PCRF AFRx+ (Rx/Gq)

Gx+ (Go/Gx)

OCS*

UE

P-CSCFMw

Cx Dx

Wa

Wg

Gm

SLFHSS*

CSCF

MRFP

IMS-MGW

Wo

D/GrDw

Mb

PDG

CGF*

WLAN AccessNetwork

Wx

MbGGSN

Wz

Wd

BM-SCGmb

Gi

MSC

Gs

PDN

**

BillingSystem*

Wf

Wy


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TISPAN R1 Reference ModelO

the

r IP N

etw

ork

s

IP Transport (Access and Core)

T-MGF

I-BGF

UPSF

I/S-CSCF

BGCF

SLF

ChargingFunctions

IWF

PES

Mw

Mw/Mk/Mm

Mr

Mg

Mj

Mi

Mp Mn

Gm

Gq'

ISCCx Dx

DhSh

Ic

Rf/Ro

Rf/Ro

Ib

Iw

Gq'

PS

TN

/ISD

N

SGFMRFC MGCF

MRFP

Resource and Admission Control Subsystem

Ie

MwIBCF

MkMk

Other types of service logic

PSTN/ISDN Emulation logic

Application ServersRf/Ro

MG

ZZ

ZZ

GW

S/TS/T

S/TS/T

AGCF

Gq'

P1 P2

P3

P-CSCF

Ut

Ut

Network Attachment Subsystem

e2e2


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WIs in 3GPP release 7 (02/2008)

• Coexistence between TISPAN and 3GPP authentication schemes study

• SAE (System Architecture Evolution)

• RAN LTE (Long Term Evolution)

• MMTel (Multimedia Telephony)

• VCC (Voice Call Continuity) between IMS VoIP and CS speech

• CSiCS (Circuit Switched IMS Combinational Service)

• SMS/MMS over IP

• FBI (Fixed Broadband access to IMS)

• IMS Emergency Calls

• PCC (Policy Control and Charging Evolution)

• E2E QoS

• AIPN (All IP Network) Feasibility Study

• Service Identification using ICSI/IARI

• Liberty Alliance and 3GPP security interworking

• Location Services for WLAN interworking

• MRFP-MRFC (Mp) Interface

• Parlay X WS:• Message broadcast• Geocoding• Application driven QoS• Device Management• Multimedia Streaming/Multicast Control

• ISIM API for Java Card


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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


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Agenda




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IMS in OMA Service Environment context

Service Binding

Applications

I0+P

I1

SP Domain

Policy Enforcer

Execution Environment

(Software Life Cycle Mgmt,

Load balancing, Caching, O&M,

etc.)

Execution Environment

(Software Life Cycle Mgmt,

Load balancing, Caching, O&M,

etc.)

ISC Sh Ut Rf Gm MbRo

I2

Non-IMS

OSE Context

Service EnablerService EnablerService EnablerService Enabler

I0Service Binding Service Binding Service Binding


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SIP

/ I

P C

ore

IM C

lien

t

XDM -3

IM-1

Re

mo

te S

IP/I

P C

ore

Aggregation Proxy

IMServer

PresenceServer

Presence XDMS

Sh

ared

Lis

t X

DM

S

PRS-5

PRS-7

PRS-8

IM -3

IM -4

IM-2

PRS-3

IMXDMS

IM-5

IM-6XDM-4

XDM-2

XD

M C

lien

t

SIP

/ I

P C

ore

XDM -1

PRS-1

PRS-2

RemoteIM

Server

RemoteIM

Client

IM-7

IM-9

IP-1

IM-8

PRS-6

Pre

s C

lien

t: S

ou

rce

Pre

s C

lien

t: W

atch

er

Charging

CH-1

DMC DMSDM-1

Shared Group XDMS

Shared XDMSs

IM -10

Shared ProfileXDMS

IM -11

SearchProxy IM-12

XDM-6

XDM-7

XDM -5

OMA SIMPLE IM Reference Model


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Limitations of ISC Service Orchestration Model

• The application server decides whether to remain linked-in for the whole session by adding its address to the Record-Route SIP header.

• 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

S-CSCFHSS

SIP-AS SIP-ASSIP-AS

I-CSCF

S-CSCFHSS

SIP-AS SIP-ASSIP-AS

I-CSCF

• 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.

Req URI = A Req URI = B

1 2


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SCIM vs. Service Broker

S-CSCF HSS

SCIM

AS AS

OSA SCS

OSA AS

IM SSF

Camel Services

ShISCISC ISC

CxSh

Si

CAP

MAP

OSA API

S-CSCF

Service Broker Service Broker

AS AS ASAS

• The Service Capability Interaction Manager (SCIM) orchestrates service delivery among application servers.

• Underspecified in TS 23.002, the SCIM has become a sort of “magic box” that would solve all issues related to service orchestration.

• Possible types of SCIM:

• AS Internal SCIM (figure above)

• SIP Broker SCIM / Service Broker SCIM

• Legacy SCIM

• The Service Broker architecture has been introduced as WI in IMS Release 8.

• The objective is to provide a coherent and consistent IP multimedia service experience when multiple applications are invoked.

• 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.

• Can be centralised, distributed or hybrid (as in the figure above).


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AS

HSS CSCF Mediaresources

Sh

ISC

H.2

48

IMS Core Network

Trusted DomainTrusted DomainAS

Parlay-X WS GW

WS Security,WS-Addressing

CustomizedCompound WS

IMS ServiceIMS ServiceEnablersEnablers

AS AS

Parlay-X, Customized interfaces

Parlay X Web Services

WS-I Basic Profile: WSDL + SOAP

WS-I Secure Profile: WSDL + SOAP + WS-Security • Parlay X Web Services is an abstraction of Parlay WS

• 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 WS-Security, WS-Policy, WS-Addressing

• 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.


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Agenda




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SOA Reference Model

Service Description

Visibility

Reachability

Functionality

Service

Service Interface

Interaction

Information model

Contract & Policy

Behavior model

Real world effect

SOA Service Description Model

What is SOA:

A paradigm which defines concepts and general techniques for the design, encapsulation and instantiation of reusable business functions using loosely coupled service interactions

SOA Reference Model:

Service

Service description

Interaction

Contract & Policy

Visibility

Execution Context

Real world effect

What is SOA:

A paradigm which defines concepts and general techniques for the design, encapsulation and instantiation of reusable business functions using loosely coupled service interactions

SOA Reference Model:

Service

Service description

Interaction

Contract & Policy

Visibility

Execution Context

Real world effect


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SOA Orchestration

SOA Characteristics

Services have well defined Service Contracts

Services are encapsulated

Services share a message bus and messages exchanged are well documented

Services can be discovered dynamically

Services are loosely coupled

Systems of services are assembled at runtime

SOA Characteristics

Services have well defined Service Contracts

Services are encapsulated

Services share a message bus and messages exchanged are well documented

Services can be discovered dynamically

Services are loosely coupled

Systems of services are assembled at runtime

Routing based on service identity (equivalent to PSI routing in IMS)

Service bus functions:

• Supports an asynchronous message based communication protocol that uses a common format encoding scheme (SOAP/XML)

• Routes, Translates and can Store and Forward exchanged messages

• Supports a Discovery mechanism

Service bus functions:

• Supports an asynchronous message based communication protocol that uses a common format encoding scheme (SOAP/XML)

• Routes, Translates and can Store and Forward exchanged messages

• Supports a Discovery mechanism

Application 1

EnablingService 1 AS1

EnablingService 2

AS2

EnablingService 3

Application 2

AS3

EnablingService 4

Appl 1

Terminal

Application 1

EnablingService 1 AS1

EnablingService 2

AS2

EnablingService 3

Application 2

AS3

EnablingService 4

Appl 1

TerminalClient


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IMS-SOA ArchitectureService Enablers:

• Provide functionality which can be used by other end-user applications (ex. Location Service)

• Unaware of the context in which they are used. Only the consumer service is aware.

Service Bus

• Handles the communication between IMS Application Servers and the Service Enablers and the communication with SOA Application Servers.

• 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.)

Service Orchestration

• 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.

CSCF

IMS ASGW AS

Service Bus

SOA AS

UDDI

SOA

IMSOrig. network

SOAP/XML

SB APISB API

Schema

Service Contract

JSR 281

Enabler

SB API

SIP MLP

MM7

Heterogeneous Service Bus IMS-SOA Architecture


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Agenda




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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


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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.


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Thank you for your attention!

[email protected]

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