Slide title In CAPITALS 50 pt Slide subtitle 32 pt Addressing & Invocation of IMS-attached Services Ioannis Fikouras, Roman Levenshteyn, Salvatore Loreto,

Slide titleIn CAPITALS

50 pt

Slide subtitle 32 pt

Addressing & Invocation of IMS-attached ServicesIoannis Fikouras, Roman Levenshteyn,

Salvatore Loreto, Gonzalo CamarilloEricsson Research

IPTComm 2007, 19-20 July, New York

Top right corner for field-mark, customer or partner logotypes. See Best practice for example.

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Text 24 pt

Bullets level 2-520 pt

© Ericsson GmbH 2007 IPTComm 2007 Adressing & Invocation of IMS-attached Services 2007-07-132 (12)

IMS & non-IMS services

The IP Multimedia Subsystem (IMS) is an IP and IETF protocol based architecture by 3GPP & ETSI TISPAN

IMS was designed as a platform for current & future telecoms & Internet services

Still, a plethora of non IMS-enabled systems and services is and will continue to be available to the subscriber

However, non-IMS services may be accessible locally to IMS terminals

An approach to provide access to such non-IMS services would extend the reach of IMS and is therefore desirable

GGSNEnterprise

BSC

CDMA2000

SIP AS

MSC(Server)RNC

UMTS/GPRS CN

SGSN

MGW

WLAN

MGW

HSS

S-CSCFP-CSCF

IMSIMS

MRF

I-CSCF

MGCF


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Introducing IMS-attached services

Attached services are: not directly addressable e.g. provided by

devices without SIP connectivity, or remotely hosted services, accessible via a

network connection

Introducing Attached Services Identifiers

ASIs support: registration of attached services in the IMS

domain (e.g. on presence servers) discovery of attached services dispatching of service requests for attached

services


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IMS-attached services identifiers

ASIs consist of three components used to:– address the IMS-enabled node (IMS URI),– identify specific types or instantiations of services (LSI)– signify service semantics (feature identifier, e.g. IANA)

Local Service Identifiers (LSI) are required to facilitate:– differentiation between multiple services with the same Feature Identifier– addressing of specific variations of attached services

Attached Serv. Identifier

IMS node URI Feature Identifier LSI

sip:[email protected] 1.3.6.1.8.4.5 (video) LSI3

sip:[email protected] 1.3.6.1.8.4.5 (video) LSI2

sip:[email protected] 1.3.6.1.8.4.1 (audio) LSI1


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Detection of IMS-attached services

Detection of attached services is achieved through:– Local discovery mechanisms for local services provided by devices

connected to an IMS terminal– Remote services can be registered via a network connection to the IMS-

enabled node

The IMS-enabled node creates the Local ASI Mapping Table containing the mapping between ASIs and attached services

Attached Serv. IdentifierAttached Serv. Desc.

IMS node URI Feature Identifier LSI Attached Serv. Address Other

sip:[email protected] 1.3.6.1.8.4.5 (video)

LSI3 192.168.1.123(IP-address)

data

sip:[email protected] 1.3.6.1.8.4.5 (video)

LSI2 192.168.1.100(IP-address)

…

sip:[email protected] 1.3.6.1.8.4.1 (audio)

LSI1 00:20:DF:E0:A3:5A (bluetooth address)

…


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Registration of IMS-attached services

Attached services should be registered in the IMS domain using their ASIs in order to enable:

– Discovery– Invocation

An appropriate registry could be a Presence server or even the CSCF itself.

PresenseServer

Detection

Detection

Detection

Detection

ASI ASD

RegistrationLocal ASI

mapping table

CSCF Registration

ASI

ASI

DiscoveryASI table

CSCF -Discovery ASI

table


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Attached service registrationvia SIP REGISTER REGISTER sip:example.com SIP/2.0 From: sip:[email protected];tag=asd98 To: sip:[email protected] Call-ID: [email protected] CSeq: 9987 REGISTER Max-Forwards: 70 Via: SIP/2.0/UDP

host.example.com;branch=z9hG4bKnashds Contact:

<sip:[email protected]>;audio=LSI1 ;video=LSI2;video=LSI3;actor="msg-taker"

;automata;mobility="fixed" ;methods="INVITE,BYE,OPTIONS,ACK,CANCEL" Content-Length: 0

The Contact header field contains :

the SIP URI in the Contact field is taken from the URI column of the local ASI mapping table

audio and video feature tags are according to IANA classification and are taken from the Feature Identifier column of the local ASI mapping table

LSIs can be omitted, in case only one service with a specific Feature Identifier is registered


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Discovery ASI mapping table

Based on the information provided by the registration process, a table consisting of all registered ASIs for an IMS-enabled node is created and maintained within a registry such as the presence server

Attached Serv. IdentifierOther data

IMS node URI Feature Identifier LSI

sip:[email protected] 1.3.6.1.8.4.5 (video) LSI3 …

sip:[email protected] 1.3.6.1.8.4.5 (video) LSI2 …

sip:[email protected] 1.3.6.1.8.4.1 (audio) LSI1 …


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Discovery ASI mapping flow


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Invocation of IMS-attached services

INVITE sip:[email protected] SIP/2.0

Via: SIP/2.0/UDP 5555::aaa:bbb:ccc:ddd];branch=z9hG4bKnashds7

Max-Forwards: 70 Route: <sip:pcscf1.visited1.net;lr>,

<sip:scscf1.home1.net;lr> From:

<sip:[email protected]>;tag=171828 To: <sip:[email protected]> Call-ID: cb03a0s09a2sdfglkj490333 Cseq: 127 INVITE Contact: <sip:[5555::aaa:bbb:ccc:ddd]> Accept-Contact: audio; video=LSI1 Content-Type: application/sdp Content-Length: 248

Accept-Contact header fields are used to select appropriate attached services for incoming invocations

The set of features specified by the Accept-Contact header field defines the set of attached services to reach


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Conclusions

This paper outlines a method for providing access to attached non-IMS services to all IMS subscribers

The approach enables the IMS terminal to act as gateway for accessing services hosted by other devices

Mechanisms for the detection, registration, discovery and invocation of attached services are presented

The proposed solution opens the way for innovative scenarios and new business cases


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Thank you!

Q&A

For more information please contact: Roman Levenshteyn [email protected]

Ioannis Fikouras [email protected]

Salvatore Loreto [email protected]

Gonzalo Camarillo [email protected]


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Documents

Slide title In CAPITALS 50 pt Slide subtitle 32 pt Addressing & Invocation of IMS-attached Services Ioannis Fikouras, Roman Levenshteyn, Salvatore Loreto,