IMS Presentation V0.3 2008-10-28

France Telecom Group restricted

An overview of the IP Multimedia Subsystem (IMS) Orange Labs

Based on IMS training courses given by R&D/Core/NAS 28/10/2008

Orange Labs - Research & Development – IMS Architecture – June 20082 France Telecom Group restricted

Agenda

Introduction IMS Architecture Access to the IMS PSTN/ISDN Simulation/Emulation Business Communications IPTV over IMS Voice Call Continuity Combined CS and IMS


Mobile context and drivers for IMS introduction

Circuit-Switched (CS) Domain– Inherently contains the call control

components for the Voice service

PS

IMS

PS

Drivers for IMS introduction: Leverage the PS Domain

– Defined by the 3GPP (part of UMTS R5)– "on top" of the PS Domain– Seen as an extension of the CS Domain in the

1st step (Replacement of the CS domain is not a priority and is postponed to a later stage)

Introduction of Packet-Switched (PS) Domain

– Internet access service only

CSVoice

CC

CSVoice

CC

CSVoice

CC


GPRS-only

Network operators provide a pure transport service (pipes)

with no control of the actual usage of these pipes

SGSN SGSNGGSN GGSN

End-to-End Signalling and

media

Signalling pathBearer path Content /Application

Server

PublicInternet


IMS on the top of GPRS

SGSN SGSNGGSN GGSN

IMS

media

Signalling pathBearer path

Content /ApplicationServer

Core ManagedNetwork

IMS - IP Multimedia Subsystem:– A SIP-based multimedia architecture, above the Packet Switched (PS) domain.


IMS at a glance A control architecture above the PS domain to fulfil network

operators needs– Basic mechanisms for multimedia session control and

access a wide range of multimedia services– including identification/authentication, QoS control,

security, charging…– Packet-based network

Choice of SIP (Session Initiation Protocol) as session control protocol

– Completed by Diameter and H.248 for other interfaces Clear functional separation between entities for :

– Session control (CSCF – Call Session Control Function)– User profile storage (HSS – Home Subscriber Server)– Service logic execution (AS – Application Server)

Separation between transport and control– eg: Entities that handle RTP flow are split into two functional

entities (controller – processor)


IMS in fixed environments

History– 2003: ETSI TISPAN adopts the IMS as the cornerstone of its NGN

architecture and start defining extensions required to make it suitable for use in xDSL-based environements

– 2005: PacketCable adopts the IMS

Benefits to all parties: vendors and operators– Saves specification and development time/effort– Enables fixed and mobile convergence– Increases the market size for IMS-based network solutions and

IMS applications development– Enables sharing of investment (CAPEX) and operational costs

(OPEX) between fixed and mobile networks.

Different initial priorities and schedules for Fixed and Mobile operators

– Mobile operators were primarily looking to the IMS as a extension to the Circuit-Switched (CS) domain

– Fixed operators were looking to the IMS as an immediate replacement solution for their CS domain (i.e. PSTN)


Silos vs. Convergence

Authentication

Charging

Session Control

User profile management

QoS / Resource management

Service-specificfeatures

Authentication

Charging

Session Control

User profile management

QoS / Resource management

Service-specificfeatures

IMS

Service #1Service #1Service #n

Service #n


Multi-services, access, devices

PSTN Emulation

Multim

edia Telehony

BusinessCom

munications

IPTV

KillerApplication?.

IP Multimedia Sub-SystemIMS

UTRAN/GERAN xDSL/FTTx WLANCable/DocsisWIMAX

Multim

edia M

essaging

Presence

Push To Talk

Backhaul/Backbone

...


IMS: a component of an overall NGN architecture The coverage of a complete NGN architecture is wider than IMS:

– IMS does not cover IP connectivity– IMS covers only SIP applications

To make up a complete NGN architecture (as defined by ITU-T), IMS has to be surrounded by other components:

Common IMS, but different NGN architectures in the standardization bodies (3GPP, ETSI/TISPAN, PacketCable)

IMS

Access dependant components dealing with specific tasks. Eg:

• Network attachment• Resources and

admission control

Components providing alternative service control environments

Full scope of an NGN architecture


An over simplistic view of the IMS

A unified multidevice, multiaccess, multiservice SIP-based control architecture over an IP transport. IMS

xDSLFTTHCable

UTRANI-WLANWIMAX

PSTN/ISDNGSM CS

IPTranspor

t


An more realistic view of the IMS

An extended SIP-based multidevice, multiaccess, multiservice control architecture over a QoS enabled IP transport.

IMS

xDSLFTTHCable

UTRANI-WLANWIMAX

PSTN/ISDNGSM CS

IPTranspor

tSIP is used for session control, mobility management and access to services

DIAMETER is used for managing and accessing service profiles, traffic policies and charging data.

H.248 is used for controlling media gateways


The truth on the IMS?

A sophisticated multidevice, multiaccess, multiservice control architecture combining a range of ITU-T, IETF and OMA technologies over a QoS enabled IP transport.

SDP, BFCP, MSRP, RTSP,XCAP, FLUTE, IGMP, MLD …

OSA APIsOMA BCASTOMA SIP PUSHINAP / CAP…

SIP (about 70 extensions” on top the “base” SIP)

DIAMETER (multiple profiles)

H.248 (multipl

e profiles

)

IMS

RTP/RTCP, IPSec, TLS , DHCP, DNSSTUN,ICE,…


Agenda



ASAS

The IMS architecture: Basic components

S-CSCF

AS

User Equipment

ISC

GmSIP

SIP

Media Flows

Mw

P-CSCF

IMS proxy, controls access to the IMS and to transport resources

P-CSCF (proxy)I-CSCF (interrogating)S-CSCF (serving)E-CSCF (emergency)

I-CSCF

E-CSCF

Mw

MwMw

Queries userdatabase

Triggers services, handles user and sessions states

CSCF: Call Session Control FunctionAS: Application ServerUE: User Equipment Provides

applications


The IMS architecture: subscriber data bases

Home Subscriber Server (HSS)

– Authentication and Authorization

– User Profile Repository (push and pull)

– User Location Repository

Subscriber Locator Function (SLF)

– Enable a CSCF to find the address of the HSS holding the profile of a particular user.

– DIAMETER Redirect server

CSCF

AS

User Equipment

ISC

GmSIP

SIP

Media Flows

Mw

SLFDx

DIAMETER

DhDIAMETER

HSS HSS

Cx

Sh


The IMS architecture: Interconnect components

Media Flows

Mw

SIP

BGCF MGCF

Mg

Mi Mj

Mk

Mx

Mx IBCF

H.248To/fromPSTN/CS

Other IP Networks

CSCF

IP-IP Border controlPSTN

Interworking

ISUPOver SIGTRAN

Decides whether a session will exit the network in IP or TDM mode

IBCF: Interconnect Border Control FunctionMGCF: Media Gateway Control FunctionBGCF: Breakout Gateway Control FunctionMGW/MGF: Media Gateway functionSGF: Signalling Gateway Function

MGWSGF

Mn


The IMS architecture: Media Resource Function

The Media Resource Function (MRF) provides

– Media sourcing (tones, announcements

– DTMF collection,– TTS & ASR,– Media mixing (conference),– Floor control (conference),– Media transcoding, and– Media recording,

under the control of an Application Server

The MRF is further decomposed into – MRF-Controller – MRF-Processor

One MRFC may control one or more MRFPs.

CSCF

ASISC

SIP

SIP

Media Flows

Mw

HSS

Cx

Sh

MRFC

MRFP

MpH.248

User Equipment

Gm Mr

MRF


The IMS architecture: the full picture

Media Flows

ISC

SIP

SLF

DxDIAMETER

DhDIAMETER

HSS HSS

Cx

Sh

GmSIPMw

BGCF MGCF

Mg

Mi Mj

Mk

Mx

Mx IBCFCSCF

Other IP Networks

H.248To/fromPSTN/CS

User Equipment

AS

P-CSCF

MRFC

MRFP

H.248

Mr

Mp Mn

MGW


Typical signaling path for a session

P-CSCF

Visited IMS

A

IBCF

P-CSCF

Visited IMS

B

IBCF

S-CSCF

AS

Home IMS

A's profile

HSS

IBCF

IBCF

S-CSCFI-CSCF

AS

Home IMS

B's profile

HSS

IBCF

IBCF


Key IMS identities

Private User Identity)

Public User Identity(s)

Home Domain Name

Primarily used for authentication

username@realm

Primarily used user to user communications

SIP URI or tel URI

IMSSubscription

PrivateUser Identity

PublicUser Identity

PublicUser Identity

PublicUser Identity

ServiceProfile

ServiceProfile

Hint for routeing initial registration messages to the

home domaindomainname


Authentication options

Mechanism Authentication Integrity protection

Support

IMS AKA plus IPsec ESP

IMS AKA IPsec ESP Mandatory for all UEs containing a UICC, else optional.Mandatory for CSCFs

SIP digest plus IP address check

SIP digest None Optional for UEsOptional for CSCFs

SIP digest plus Proxy Authentication

SIP digest None Optional for UEsOptional for CSCFs

SIP digest with TLS SIP digest TLS session

Optional for UEsOptional for CSCFs

Early IMS Trust GPRS authentication

None Optional for GPRS-based UEsOptional for CSCFs

NBA Trust-by-wire None Optional for "fixed" UEsOptional for CSCFs


IMS Service Access: Architectural options

Sessions are routed to Application Servers because:

– The initial request matches certain filter criteria

– The destination is a Public Service Identity (PSI)

PSI: Similar to public uder identities but allocated to services (AS) rather than users.

– tel: +33 800 22 22 11– sip:

[email protected]

S-CSCFS-CSCF

SIP Application Server

SIP Application Server

HSSHSS OSA service capability server

(SCS)

OSA service capability server

(SCS)

IM-SSFIM-SSF

Camel Service Environment

Camel Service Environment

OSA application

server

OSA application

server

ISC

Cx ISC

ISC

CAPMAP

OSA API

SCIM

AS AS

Sh

Si

MRFCMRFC

Mr

mailto:[email protected]


Filter criteria processing (simplified view)

service logic

SIP driver

service logic

SIP driverAS-1 AS-

2

iFC#1? iFC#2?

Y

N

Y

N

Incoming INVITE1

2a 3

2b

4a

4b

5

SIProuteing

S-CSCF

iFCs are stored in the HSS and downloaded to S-CSCF as part of the user profile during registration


IMS Service Access: Initial Filter Criteria

Service ProfilePublic User Identity

Priority

Application Server

Trigger Point

Service Point Trigger

Initial Filter Criteria

Example: Method = "INVITE" AND (Header = "from" Content = “francis.faller")

Registered/Non Registered

Default handling


UE

REGISTER sip: ims.orange.fr SIP/2.0To: Bruno Chatras <sip:[email protected]>From: Bruno Chatras <sip:[email protected]>Contact: <sip:[email protected]>

S-CSCF

P-CSCF

I-CSCF

2

HSS

5

8

After 5, the S-CSCF knows the terminating P-CSCF for the UE (Path header)After 7, the S-CSCF knows the UE's Service Profile

IMS Registration

REGISTER sip: ims.orange.fr SIP/2.0To: Bruno Chatras <sip:[email protected]>From: Bruno Chatras <sip:[email protected]> Contact: <sip:[email protected]>Path: <sip:[email protected];lr>

REGISTER sip: scscf1.ims.orange.fr SIP/2.0To: Bruno Chatras <sip:[email protected]>From: sip:[email protected]>Contact: <sip:[email protected]>Path: <sip:[email protected];lr>

67

34

9

110

200 OKPath: <sip:[email protected];lr>Service-Route: <sip:[email protected];lr>To: Bruno Chatras <sip:[email protected]>From: Bruno Chatras <sip:[email protected]> Contact: <sip:[email protected]>P-Associated-URI: tel:+336738951317;sip:[email protected]

After 10, the P-CSCF knows the S-CSCF (service-route) and the list of public user identities.


Originating session

Applications

S-CSCF

P-CSCF

1

2

43

INVITE tel:+31161255678From: Bruno Chatras <sip:[email protected]> To: Francis Faller < tel:+31161255678>P-Preferred-Identity: tel:+33673895317

I-CSCFIBCForange

IBCFteliasonera

HSS

6

ENUM lookup

5

The P-Preferred-Identity matches the implicit

registration set, therefore the P-CSCF can assert this

identity.

UE

INVITE tel:+31161255678From: Bruno Chatras <sip:[email protected]> To: Francis Faller < tel:+31161255678>Route: <sip:[email protected];lr>P-Asserted-Identity: tel:+33673895317

INVITE sip:[email protected];user=phoneFrom: Bruno Chatras <sip:[email protected]> To: Francis Faller < tel:+31161255678>Route: <sip:ibcf1.orange.fr;lr>P-Asserted-Identity: tel:+33673895317


Terminating session

S-CSCFOperator.com

Ext. 5678

8

S-CSCF

P-CSCF

7

65

I-CSCF

HSS

4

2 3

IBCFoperator.com

IBCForange

1

Applications

LIR LIA

- LIR Location Information Request- LIA Location Information Answer

INVITE sip:[email protected];user=phoneFrom: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33673895317 >P-Asserted-Id: tel:+31161241234

UE

INVITE tel:+33673895317From: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33673895317 >P-Asserted-Id: tel:+31161241234Route: scscf1.ims.orange.fr

INVITE sip:[email protected]: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33673895317 >P-Asserted-Id: tel:+31161241234Route: [email protected]: tel:+33673895317


Agenda



Differences between Fixed and Mobile access

Inherent differences between wireless/ wireline access – Different constraints in terms of bandwidth scarcity,

security, transmission delay..

Different assumptions/constraints on user equipment types and behaviour

– Supported codecs, authentication schemes, IP version, hosted NAT in customer premises, location awareness, ability to request transport ressources…

Differences in the provision of IP connectivity – Different admission control procedures in the

access/aggregation network – Different network attachment procedures


UTRAN/GPRS access to the IMS

Prior to communication with the IMS subsystem, the UE shall:

– perform a GPRS attach procedure and ensure that a PDP context used for SIP signalling is available (dedicated or general-purpose)

– acquire a P-CSCF address(es). – using DHCP or PDP context signalling procedures

Media streams are carried using the same or additional PDP contexts (secondary)

GGSNIP BackboneGPRS

SGSN

IMSSIP


UTRAN/GPRS access to the IMS

P-CSCF

S-CSCF

IMS

PCRF

GGSN

Policy and Charging controlDynamic configuration of transport nodes

Rx (DIAMETER)

HSSSLF

HLR

…Mw

Cx

Dx

IP BackboneGPRS

AS

ALG/NAT

Dynamic NAPT/Firewall

Gm

ISC

Iq

SGSN

UPSF

Go


DSL Transport resource for accessing the IMS

Transport Functions are provided by a DSL segment and an aggregation segment. The aggregation segment is usually based on ATM or Giga Ethernet

Static layer 2 resources (VLAN and/or ATM VC). Usually Layer 2 resources are dedicated to IMS traffic and both signalling and media share the same resources.

DSLAM/MSAN BRAS / BNG

Aggregation Segment ATM VP or VLAN GE

NAT/FW

ATM VC

DSL Segment

IP-Connectivity Access Network (IP-CAN)

IP Backbone

IMSSIPIP


DSL access to the IMS

P-CSCF

S-CSCF

IMS

DS

L Modem

RouterWith NAPT/FW

HGWGW

NASS

RACS

DSLAM BRAS/BNG

Network Attachment(IP@allocation, Authentication, Authorisation, Location Repository…)

Admission ControlDynamic configuration of transport nodes

e2 (DIAMETER)

Re (DIAMETER)

CLF

HSSSLF

UPSFHLR

…Mw

Cx

Dx

IP BackboneATM or GEaggregatio

n

Ia (H.248)

AS

ALG/NAT

Dynamic NAPT/Firewall

Gm

ISC

Gq' (DIAMETER)


Agenda


PSTN/ISDN Simulation: Provides PSTN/ISDN-like service capabilities using session control over IP interfaces and infrastructure.

PSTN/ISDN Emulation: Provides PSTN/ISDN service capabilities and interfaces using adaptation to an IP infrastructure.


The IMS Architecture vs CS architectures

Media Flows (RTP)

MwP-CSCF S-CSCF

MwP-CSCFS-CSCF

SIPSIP

AS AS

ISUP

TDMTE TELE LE

SIP

Class 5 (Telephony)

logic


Simulated PSTN/ISDN Supplementary services

TS 183 004 Communication diversion

TS 183 005 NGN CONF/3PTY TS 183 006 NGN MWI TS 183 007 OIP/OIR TS 183 008 NGN TIP/TIR TS 183 010 NGN HOLD TS 183 011 ACR & CB Stage 3 TS 183 015 Call Waiting TS 183 016 NGN MCID TS 183 029 NGN ECT TS 183 042 CCBS TS 183 047 Advice of Charge TS 183 054 CUG

Each document includes a specification of

– the UE and AS behavior and rules for populating SIP headers

– an XML schema for use in service configuration procedures

– any other XML schema that may be used in SIP bodies (e.g. AoC information in TS 183 047)


PSTN/ISDN Emulation architectures

Two flavours– IMS-based: IMS architecture extended with adaptation

functions at the edge (TS 183 012).– Softswitch based: A wrapper around vendor-specific

implementations based on re-using the call control software of a legacy switching centre (ES 282 002 and TS 183 043).

IMS architectural extension: Access Gateway Control Function (AGCF) acting as:

– a combined UE/P-CSCF with regards to the S-CSCF– an MGC with regards to media gateway functions.

Type of access supported– Support of Analogue access– Support of ISDN access


DSL access to the IMS (baseband) – Option 1

P-CSCFS-CSCF

DS

L Modem

RouteurWith NAPT/FW

HGWGW

NASS

DSLAM BRAS/BNG

e2

ALG/NAT

Gq'

HSSSLF

HLR

…

Mw

Cx Dx

IP Backbone

Ia

AS

Z

AGCF

p1(H.248 + Q.931/SCTP)

A-MGF

Mw (SIP +XML)

Gm

RACS

UPSF

ISDN


DSL access to the IMS (baseband): Option 2

P-CSCFS-CSCF

DS

L Modem

RouteurWith NAPT/FW

HGWGW

NASS

DSLAM BRAS/BNG

e2

ALG/NAT

Gq'

HSSSLF

HLR

…

Mw

Cx Dx

IP Backbone

Ia

AS

ZGm (SIP+XML)

VGW

Mw (SIP +XML)Gm

RACS

UPSF

ISDN


PSTN/ISDN Emulation: analog access

Tight Coupling: No feature logic available in the AGCF

– e.g. Register Recall events are reported by the AGCF to an Application Server

Loose Coupling: Limited feature logic resides in the AGCF

– e.g. delivery of dialtone upon detection of a Register Recall event

– The AGCF appears to the AS almost as a "normal" SIP phone or "Box".

AGCF

MGF

AS

Core IMS

Line events/signals

H.248 Events/SignalsSwitching and Transcoding

SIP

PSTN service logic


PSTN/ISDN Emulation: ISDN access

DSS.1 encapsulation– DSS.1 information

converted to XML format if cannot be mapped to any SIP header.

– Palliative to the shortcomings of SIP in terms of signalling information transported.

Not to be confused with SIP-I (Q.1912.5) or NSS (Q.1980).

AGCF

MGF

AS

Core IMS

D-Channel.

H.248 switching and transcoding

SIP (+XML)

B-Channel. RTP

ISDN service logic

SIP (+XML)


Agenda



Business Communications Scenarios

Virtual leased line: NGCN sites are interconnected through the NGN using IP VPN tunnels;

Business Trunking: The NGN hosts transit capabilities between NGCNs, break-in and break-out capabilities from NGN to NGCN and possibly additional services;

Hosted Enterprise Services: The NGN acts as a virtual PBX with regards to a distributed collection of users.

– Commonly known in the industry as "IP Centrex". Next Generation Corporate Networks (NGCN) NGCN Site ~1 or more IP PBX


Hosted Enterprise Services

ETSI TS 182 024 specifies the realisation of Hosted Enterprise Services using the IMS.

– Endpoints are connected to the IMS at the Gm reference point and appear as normal User Equipment.

– Application Servers provide the logic of a Virtual IP PBX.– Private Numbering Plans can be used

IMS

Basic Endpoint Basic Endpoint

Virtual PBX Logic

PSTN/ISDN services,Messaging, PresenceConferencing,Abbreviated dialling,Unified Voice mail,Operator assisted calls,Hot Line Calling,Line Hunting,Attended/Blind Communication Transfer,Communication Pickup,Manager / Secretary filtering,


Business Trunking

ETSI TS 182 025 specifies the realisation of a business trunking solution using the IMS. Two variants are identified:

– Subscription-based: The PBXs are connected to the NGN at the UNI (i.e. they are seen as a particular type of User Equipment).

– Peering-based: Corporate Networks are seen as peers of public networks and are therefore connected at the NNI.

Supported features– Transit, Break-in, Break-out– Private numbering– Bulk re-routeing

– (e.g. all calls to a particular NGCN site are rerouted to a configured destination during closed hours)

– Service-level communications Admission-Control (e.g. maximum number of sessions per PBX)

– Barring of all communications to a PBX


Business Trunking

Core IMS

AS

Business Trunking Logic

Core Transport

UPSFPBX profiles


Subscription-based Business Trunking

Each site of the NGCN has a service subscription to the IMS and must support SIP registration.

Private extensions behind the NGCN do not need their own service subscription, since they are owned and managed by the NGCN.

Each NGCN site is allocated – a pair of private and public user identities for use at

registration time. – one or more Wildcarded Public User Identity.

– NOTE: A wildcarded public user identity expresses a set of public user identities grouped together (e.g. tel: +3314529!****!) and can be included in an implicit registration set.


PBX

REGISTER sip: ims.orange.fr SIP/2.0To: [email protected]:[email protected]: <sip:[email protected]>

S-CSCF

P-CSCF

I-CSCF

2

HSS

5

8

After 5, the S-CSCF knows the terminating P-CSCF for the PBX (Path header)After 7, the S-CSCF knows the PBX's Service Profile

IMS PBX Registration

REGISTER sip: ims.orange.fr SIP/2.0To: [email protected]:[email protected]: <sip:[email protected]>Path: <sip:[email protected];lr>

REGISTER sip: scscf1.ims.orange.fr SIP/2.0To: [email protected]:[email protected]: <sip:[email protected]>Path: <sip:[email protected];lr>

67

34

9

110

200 OKPath: <sip:[email protected];lr>Service-Route: <[email protected];lr>To: [email protected]:[email protected]: <sip:[email protected]>P-Associated-URI: tel:+33145294444; tel:+3314529!****!;sip:[email protected]

After 10, the P-CSCF knows the S-CSCF (service-route) and the list of public user identities (including the wildcarded range).

- Normal IMS Level Registration Flow (first round-trip not represented)- PBX Identity is provisioned in the HSS- PBX is registered with this PBX Identity- Number range is asscoiated to PBX identity by means an implicitly registered wildcard PUI- PBX indicates support of ua-loose in the REGISTER request or this indication is received from the HSS (part of the user profile)

Subscription for PBX Identity, implicit

registration set contains a wildcard PUI


Terminating session

S-CSCFOperator.com

8

P-CSCF

7

65

I-CSCF

HSS

4

2 3

IBCFoperator.com

IBCForange

1

BusinessTrunking

Applications

LIR LIA

- LIR Location Information Request- LIA Location Information Answer

INVITE sip:[email protected];user=phoneFrom: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33145294148 >P-Asserted-Id: tel:+31161241234

PBX

INVITE tel:+33145294148From: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33145294148 >P-Asserted-Id: tel:+31161241234Route: scscf1.ims.orange.fr

INVITE tel:+33145294148From: Francis <tel:+31161241234>To: Bruno Chatras < tel:+33673895317 >P-Asserted-Id: tel:+31161241234Route: <sip:[email protected]>Route: <sip:[email protected]>P-Called-Party-Id: tel:+33145294148

Service profile PBX Identity, matches

Wildcarded PUI in Implicit Registration set

Optionally trigger onIFC from

PBX Identity

Applies "loose route" procedure as a result of havin received a "ua-loose" route indication from the UA or the HSS at registration time.

9

S-CSCF


Agenda



IPTV

IPTV services: Content on Demand (CoD), Live Media Broadcast (BC) with and without trick mode and time shitfing, Network-based recording (PVR)

Two solutions under standardisation– Integration in NGN: Wrapper around legacy systems– Integration in IMS

Rationale for using the IMS– Leverage the IMS platform by adding one more service on top of it!– Unified framework for authentication, identification, charging and

profile management for both communication services and content delivery services

– Easy integration of communication services and content delivery services, through standard IMS inter-AS communication procedures.

– Call Forwarding (to Mailbox) when watching TV/VOD,– Virtual Living Room, See what I See,– Caller ID on TV with or without TV Pause services,– Automatic TV/VoD Pause on Incoming Call Acceptance,…


High Level Architecture for IMS-based IPTV

Core IMS(CSCF)

IP-TVService

Control

DiscoverySelection

Transport Processing

User E

quipment

Media Control

Media Delivery

MediaFunctions

Content

FunctionsOther NGN Applications

Management

Network Attachment

NASS

Resource AllocationRACS

UserProfile

TS 182 027


IPTV High Level procedural steps (CoD)

IMS Registration (SIP/IMS)

Service Discovery (SIP/IMS)

Session Management (SIP/IMS)

Content Control (RTSP)

Content Delivery (RTP)

Service Selection (HTTP)

Network Attachment

UE SCF(AS)

SDF(AS)SSF MFNASS IMSAN


IPTV High Level procedural steps (Broadcast)

IMS Registration (SIP/IMS)

Service Discovery (SIP/IMS)

Session Management (SIP/IMS)

IGMP

Unicast content

Service Selection (HTTP)

Network Attachment

UE SCF(AS)

SDF(AS)SSF MFNASS IMSAN

Multicast content

Multicast control


SIP procedures for IPTV CoD

Resource Reservation andCommit

INVITE

200 OK(INVITE)

INVITE (R-URI = Content Id)

200 OK(INVITE)

UE RACS IMS MFMF

INVITE

200 OK(INVITE)

RTSP PLAY

Resource resevationSDP Offer for a control channel (RTSP) and one or more content

channels

SDP Answer

Final decision + firewall opening

Content

Work in Progress


SIP procedures for IPTV Broadcast

Resource Reservation and Commit

INVITE

200 OK(INVITE)

INVITE (R-URI = BC Service)

200 OK(INVITE)

UE RACS IMS SCFAN

IGMP Join

Resource Control

Contents

Resource Reservation

SDP Offer for multicast traffic

SDP Answer with authorised list of

multicast channels

Final decision (based on user access) +

firewall opening for all channels

Fine tuning of bandwidth reservations

Admission control for resources beyond the AN (in case of

zapping to a channel that is not already received)

MF

Work in Progress


Agenda



Voice Call Continuity

Allows to transfer a CS voice call to a VoIP call– Can be used to provide subscribers services like UNIK

Solution based on IMS– A specific IMS AS is defined for this: VCC AS

– This VCC AS is connected to both CS domain and IMS domain

– Typical scenario is to swith a voice call initiated under WLAN coverage to a mobile CS access


Voice Call Continuity

Architecture principles:

IMS domain

MSCMobile circuit domain (eg. GSM)

Fixed Access Network

Application ServersVCC AS

MGCF

Anchor Point for call establishment, associated to feature for Network selection

SIP Signalling flow

ISUP/BICC Signalling flow

Camel triggering


Agenda



Combined CS and IMS

Goal:– Handling of real-time services such as VoIP with IMS

will be an issue on mobile access

CSI Phase1:– Short Term solution with main impacts on terminal– Voice call are kept in the CS domain– IMS sessions are used for non real-time services like

IM

CSI Phase2:– Long Term solution where CS Bearers are controlled

by IMS


Combined CS and IMS CSI Phase1 Architecture:

CSI Phase2 Architecture:

IMS

CS

non real-time servicese.g. messaging

Voice component

User sees a call with

combined voice and

messaging services

PS PS

CS CS

IMS

CS

non real-time servicese.g. messaging

Voice component

Pure VoIP UE

PS PS

CS

CSI UE

CSI UE CSI UE


Conclusion


People like criticizing the IMS…

"IMS is unnecessary for many services, particularly non-SIP services. Even for services that do need SIP, much can be done without using IMS."

"IMS has a dated, backward looking view of services and applications. We are now living in a world of Web 2.0, Web services, mash-ups, and SOA, after all."

"IMS propagates a telco-oriented view of the network, where services are provided by network intelligence, rather than by edge-device intelligence – the intelligent-network/dumb-network argument."

"IMS is costly, bloated, overcomplex, overambitious, and will either never work properly or never be fully implemented. "

From Heavy Reading (based on comments received on their web site)

http://www.lightreading.com/document.asp?doc_id=138038


… but vendors and operators seem to believe in it!

Terms like IMS-based, IMS-enabled, and IMS-ready abound in vendor product pitches

– By September 2007, Ericsson, for example, was citing 39 IMS system contracts for commercial launch and more than 80 trials.

– Alcatel-Lucent had, as of September, more than 20 full IMS references ("full" meaning the implementation of a CSCF, HSS, AS, and two or more SIP applications) in various stages of deployment, trials, and commercial rollout; and more than 50 customers using IMS application servers and services supplied by the company.

– Nortel cites 20 IMS contracts and pilots completed or ongoing with carriers worldwide.

– Nokia Siemens Networks claims more than 30 commercial references for its IMS core in wireless and wireline networks worldwide, and more than 155 references for the IMS core and applications combined.

A Heavy Reading survey in 2006 found that most service providers still consider IMS an essential part of their strategy, "though a significant minority – 30 percent of respondents – remains unconvinced about it."

From Heavy Reading (What's up with IMS)



… what about the analysts views?

In 2010, 77 percent of all investment for call control layers is forecast to be based on IP Multimedia Subsystem (IMS) architecture, while 23 percent will continue to go into enhanced softswitch technologies)

The IMS technology forecast has been pushed back by approximately two years due to a lack of carrier belief in immediate real-world deployability of the architecture in a true fixed-mobile converged, mass-market service environment”.

Gartner 2006 Gartner 2008


Conclusion

IMS opens new opportunities for operators– Converged architecture– Development of new enhanced services

BUT– Still at the beginning of IMS, maturity not reach in live

networks– First step: to be able to recreate the same level of

services offer with IMS– Second step: create more and more Enriched Services


More Information


More Information

Where to find Latest Drafts and Published Standards?– http://portal.etsi.org/docbox/tispan/Open/– http://www.tech-invite.com/Ti-tispan-standards.html– http://p-xllesandelys.rd.francetelecom.fr– or I:\NORMALISATION\Etsi_Tispan (R&D shared directory)

Internal Web Resources (OGSR)– https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=TISPAN– https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=Introduction_to_NGN– https://ogsr.rd.francetelecom.com/wikidraft/index.php?title

=Corporate Networks

External Web Resources– http://www.lightreading.com/document.asp?doc_id=95511&page_number=5– http://www.lightreading.com/document.asp?doc_id=70728– http://portal.etsi.org/docbox/tispan/Open/Information/NGN_Presentations/TISPAN_Overview_by_Cisco_Tazz.pdf

http://portal.etsi.org/docbox/tispan/Open/

http://www.tech-invite.com/Ti-tispan-standards.html

http://p-xllesandelys.rd.francetelecom.fr/

https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=TISPAN



https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=Introduction_to_NGN

https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=Introduction_to_NGN

https://ogsr.rd.francetelecom.com/wikidraft/index.php?title=CorporateNetworks



http://www.lightreading.com/document.asp?doc_id=95511&page_number=5


http://portal.etsi.org/docbox/tispan/Open/Information/NGN_Presentations/TISPAN_Overview_by_Cisco_Tazz.pdf

http://portal.etsi.org/docbox/tispan/Open/Information/NGN_Presentations/TISPAN_Overview_by_Cisco_Tazz.pdf

France Telecom Group restricted

thank you

Orange, the Orange mark and any other Orange product or service names referred to in this material are trade marks of Orange Personal Communications Services Limited. © Orange Personal Communications Services Limited.

France Telecom Group restricted.

http://www.tispan.org

http://www.tispan.org/


Annex


User controls on simulated services Services can be configured by

the end user, by uploading XML documents into the network, using the XCAP protocol.

CSCF

AS

User Equipment

ISC

GmSIP

SIP

Media Flows

Mw

SLFDx

DIAMETER

DhDIAMETER

HSS

ShUt

XCAP (http)

Documents

IMS Presentation V0.3 2008-10-28