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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
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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
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IMS Subsystem
Cx
Mm
AS
ISCSh
Ut
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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