IMS and Media Control

James Rafferty, Cantata TechnologyAugust 10, 2007

IMS and Media Control

IMS and Media Control

• Relationship to Overall IMS• Media Resource Function

– Prior Art– Relationship to Application Servers– MRFC– MRFD

• MRF Interfaces• Putting the MRF to Work• Application Examples

P-CSCF

S-CSCFMGCFHSS

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IP Multimedia Networks

IM-MGW

CS Network

Mc

Mb

Mg

Mm

MRFP

Mr

Mb

Legacy mobile signalling Networks

I-CSCF

Mw

Mw

Gm

BGCFMjMi

BGCF

Mk Mk

C, D, Gc, Gr

UE

Mb

Mb

Mb

MRFC

SLFDx

Mp

CS

CS

IMS Subsystem

Cx

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AS

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3GPP TS 23.228 V7.2.0 (2005-12)

The IMS Architecture

IMS focus for Media control:

MRF

Media Resource Function

• 3GPP has borrowed the MRF concept from several sources

• Basic idea of MRF or Media Server is to service the media needs of applications– Collect Digits, Process tones, voice

play/record, video play/record, …

MRF Prior Art• MRF concepts derived from several

predecessors– Concept of Decomposed architecture came from

Softswitch Movement (ISC, ITU, IETF)– Concept of SIP for Media Server control begun by

Snowshore and validated by IPCC Reference Architecture

– Several companies have been working with SIP plus XML based markup languages for Media Control over last few years

• Several variants including Netann (RFC 4240), VoiceXML, MSCML, MSML/MOML

Timeline for Media Server Protocols

MGCP

1999 2000

SIP/netann

SIP/MSCML

2001 2002 2003 2004

H.248

H.248.1

SIP/MOML-MSML

Time

Util

ity f

or M

edia

Ser

ver

Media Server Afterthought; Not IETF Standard

Fixed MGCP Problems; Focus on Gateways; IETF Standard

Multifunction Media Server Interface; SIP Paradigm

Conference-Control Optimized Interface for SIP Environment RFC Editor Queue

Added Basic Media Services for Device Control Applications; No known applications

“All the Features of MGCP, But With SIP Transport”

SIP/MSML

Attempt to Address Intellectual Integrity Issues

MRF ArchitectureComponents

App ServerISC

S - CSCF

MRFP

MRFC

Mr (SIP)

Mp (H.248)

• Lots of discussion on best way to handle in 3GPP / IETF

• Some implementers will combine MRFC/MRFP (MRF)

MRFC

• MRFC = Multimedia Resource Function Controller

• Definition: – MRFC can accept SIP Invites requesting

tones and announcements, ad-hoc conferences and transcoding

– Works with MRFP on carrying out media operations if not a combined MRFC/MRFP

MRFP

• MRFP = Multimedia Resource Function Controller

• Definition: –     Provides resources to be controlled by the

MRFC–    Mixes incoming media streams (e.g. for multiple

parties).–     Sources media streams (for multimedia

announcements).–    Processes media streams (e.g. media analysis).

Related Interfaces

• Mr (S-CSCF – MRFC) interface– Based on SIP

• Active work item in 3GPP; related work in IETF

• Mp (MRFC - MRFP) interface– Based on H.248 (Megaco)

• Active work item in 3GPP; related work in ITU-T

The Controversy

• Most robust media servers are controlled via SIP

• 3GPP specified media interfaces only at high level up until now– SIP for Mr (to control MRFC)– H.248 for Mp (to control MRFP)

• Many leading MS vendors strongly support a SIP-only MRF– However, 3GPP is moving ahead with H.248 as

the protocol for the Mp interface

Issues with MRFC/MRFP Decomposition

• With no Media Processing Experience– Belief Was MRFC:MGC::MRFP:MG– Lots of Media Resources Controlled By Controller

• Separates Media Control (“Control Plane”) From Media Processing (“Media Plane”)

MGC

MRFP

MRFPMRFP

MRFP

MRFC

MRFC

What Is Today’s Reality?

• MRFC Capacity– 600 Sessions/Box (VoiceXML)– 1000 Sessions/Box (Trivial IVR, Basic Conferencing)

• MRFP Capacity– Early Media Servers: 20,000 Sessions/Box– Ratio MRFC:MRFP in deployment is at Least 20:1

MRFP

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFCMRFC

MRFC

Another Possible Approach• Network Function Required

– MRFC Capability Discovery– MRFC Allocation & Load Balancing– Consolidated CDR, OAM, Provisioning

• Media Resource Function Broker (MRFB)

MRFC

MRFP

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFC

MRFCMRFC

MRFC

MRFCMRFCMRFC

MRFC

MRFB

Potential MRFB Interfaces

• Clearly, MRFB Uses Mr (SIP) to S-CSCF– Do Not Change S-CSCF

• Should MRFB use H.248 or SIP to MRFC?– H.248 Would Change MRFC– Creates many Technical Issues Raised Above

• MRFB Makes Collection of MRFC/MRFP (MRF) Look Like Single Media Resource

Putting the MRF to Work

NFS

HTTP

FTP

NetworkStorage

Web Content

mp3Win Media

Text

Video Ringback

VideoConferencing

Gaming

SponsoredCalling

SIPMSCML

Conferencing

Video MailAnnouncements

RTP

Pre-Paid Voice Mail

SIP

(MRFC/MRFP)

IP MSC

MGW

CMTS

SIP

SIPSIP w/ VoiceXMLSIP w/ MSCML

UnifiedMessaging

SIP

SIPVoiceXML

MPEG-4

IMG

IMG

SIP Routing Cloud

3G

2.5G

PSTN

Cable

IPPhones

S-CSCF / SCIM

MRF

Example: IMS Network Gaming Demo

• Developed with IBM and partners– Qualphone client on mobile handset– Uses “presence” for user availability– MRF provides conferencing (“trash talk”) and IVR– Terraplay “Lock n’ Load” Multi-player game

IMS Gaming Service Delivery

PLMNPLMN

Outbound T1 PRI

CDMA Mobile Calls

CDMA Mobile Call

Qualphone Client

WiF

i

Gaming Data

Gaming Data

CantataMRF Terraplay

Game

IBM Presence

Ubiquity SIP AS

BayPacketsPrepaid

BayPacketPrepaid

NexTone CSCF

MGW-IMG

Example: Sponsored Call Service

• Developed by ARGELA Technologies

• “Sponsored Call”– 3G subscriber views a

video commercial from a “sponsor”

– Subscriber receives a discount on service

• Rapid development– 4 weeks from

development to trial

Benefits of Sponsored Call Service to…

Subscribers Sponsors Providers• Saves $$

• Useful promotions

• Multimedia channel of advertisements

• Interactive promotions, campaigns and surveys

• Select the customer segments

• New revenue stream from the sponsors

• Increased air time and revenue

Case Study: Video Messaging Deployment

• Developed by OpenWave

Service Features• 3G VideoMail

– Greeting– Message drop-off– Subscriber retrieval

• VoiceMailConverged Application• Access From PC Over

Broadband As Well As Wireless

Provider: TMN – With more than five million subscribers in Portugal and a total of 25 million accounts worldwide, TMN is Portugal’s largest mobile operator.

New video service deployed for European Soccer Championship

Games in Portugal 2004

Other Likely IMS Applications

• FMC – Fixed Mobile Convergence• IP Centrex Hosting for Businesses• Audio and Video combined with other

services– For example, conferencing, push-to-communicate,

Multimedia over Broadband, Multimedia IM

• Legacy Migration– Voice mail, conferencing, SMS, Prepaid Services

Workshop Questions

1. What are some examples of media within an MRF?

2. What are examples of “prior art” that are influencing the MRF?

3. Which protocols are proposed to control the following IMS elements?

• MRFC • MRFP

Summary

• MRF is the Media Resource Function in the IMS

• Strongly influenced by prior art in control of Media Servers

• 3GPP is working on standards for MRF control, with IETF and ITU– Still much debate in standards bodies about

details

• Pre-IMS solutions using SIP and XML markup are being deployed today