Multimedia Gateways
& H.248/ MEGACO
ITU Workshop on IP Networking &
MEDIACOM-2004
April 26, 2001
Presented byClifford Sayre, Lucent Technologies
Multimedia Gateways
•
This presentation is the joint work of several teams:
•
NTT DoCoMo
– Takashi Suzuki - (ITU-T SG 16 delegate)
•
NTT DoCoMo Communications Laboratories USA
– Muhammad Mukarram Bin Tariq
– Shahid Shoaib
•
Lucent Technologies
– Clifford Sayre - (ITU-T SG 16 delegate)
2
Overview
• Introduction to IMT-2000 & New Capabilities
•
Emerging Wireless Multimedia Applications
• H.324M/ 3G-324M Standard for Wireless Multimedia
• Interworking with the ITU-T H.3XX Series
• MEGACO/H.248 as Key Element in Interworking
Gateway
3
Features of IMT-2000
•
High Speed Data and Video Transmission
– Maximum bit rate: 384kbps (outdoor), 2Mbps (Indoor)
•
Global Mobility
•
High quality transmission
– Appropriate quality for each application can be provided
– From 10-3 to 10-6
•
Improved Frequency Efficiency
– The same frequency band can accommodate a greater number of
users
•
The network platform for the Mobile Multimedia Applications
– Video Phone
– Video Mail
– Video Distribution (streaming / download)
4
Bearers of IMT-2000 and the Type
of Services
Type of Bearers
Circuit Switched
Bearers
Voice Communication
Voice
Non-specified Digital
Internet
Audio／Video
Communication
Packet Switched
•
Services to be Covered
Packet
Video phone (3GPP 3G-324M)
Internet
Audio/Video Application over Circuit Switched Bearer
–
–
Based on 3GPP 3G-324M
Various applications with 3G-324M
» Video phone
» Video mail / Video answering
» Audio/Visual content distribution
•
Interworking between 3G-324M and other networks
–
Important to launch mobile multimedia successfully
5
Interworking Between Multimedia
Terminals
•
•
Interworking with Multimedia terminal on the Internet
Interworking with Multimedia terminal on the PS mobile network
•
3G-324M – H.323/SIP Interworking
SS7
MGC
H.248
3G-324M
Circuit Switched
Mobile NW
Packet Switched
Mobile Network
MT (PS)
(SIP/H.323)
MG
Internet
H.323/SIP
6
3GPP 3G-324M Overview
• ITU-T developed H.324 Mobile extension (H.324M)
– H.324 Annex C has been established in ’98.2
– Improved error robustness
» Error robust multiplexing (H.223 Annex A ~ C)
» Efficient transport of H.245 control messages
• 3GPP extended H.324 Annex C
– 3G-324M has been established in ’99.12
– Specified the audio/video CODECs suitable for Wireless Network
» Mandatory support of AMR speech CODEC
» Mandatory support of H.263 baseline
» Optionally but recommended support of MPEG-4 Simple Profile @ Level 0
– Specified the multiplexing for Wireless Network
» Mandatory support of H.223 Level 2 (Annex B)
– Added several clarifications
» Based on the interoperability test carried out by the interested companies
» Described in 3G-324M Implementor’s Guide
7
Building Blocks of 3G-324M/ H.324M
Wireless
Network
H.223 Annex B
H.223 multiplexed bitstream is mapped onto digital channel
Bearer control messages are delivered as in-band data
Modem/Mode negotiation is not applied
Wireless Network I/F
•
•
•
Call Control
Out-band
Bearer Control
H.245
In-band
Audio CODEC
AMR
Video CODEC
H.263/MPEG-4
8
Interworking With H.323
•
Interworking with H.323 system requires:
Mapping of Call Control Signaling
Mapping of Bearer Control Signaling (I.e. H.245)
Conversion of Media Transport Format
Media Transcoding
Q.931/H.225.0
Bearer Control
H.245
Bearer Control
H.245
Audio CODEC
AMR
Audio CODEC
Video CODEC
H.263/MPEG-4
Video CODEC
IP
Call Control
TCP
H.323
H.223 Annex B
Wireless Network I/F
3G-324M
RTP/UDP
–
–
–
–
9
Interworking with SIP
•
Interworking with SIP requires:
– Mapping of Call Control /Bearer Control Signaling to SIP/SDP
– Conversion of Media Transport Format
– Media Transcoding
Audio CODEC
AMR
Audio CODEC
Video CODEC
H.263/MPEG-4
Video CODEC
IP
Bearer Control
H.245
SIP/SDP
RTP/UDP
Call Control
TCP or UDP
SIP
H.223 Annex B
Wireless Network I/F
3G-324M
10
Interworking & Gateway Decomposition
• Requirements for gateway
– Decomposed GW shall be able to achieve the same
interworking functionalities as Monolithic GW
– Able to communicate with any 3G-324M/ H.324M compliant
terminal
– Easy to achieve compatibility between MG and MGC from
different vendors
– Less interactions between MG and MGC are better
» For compatibility between MG and MGC
» For reduction of signaling traffic (to accommodate tens of millions
of customers)
11
Gateway Configuration
• Proposed configuration
–
–
–
–
–
H.248/ MEGACO protocol for MGC to MG control
MGC for call control/ signaling
MG for media stream processing
MG or MGC for media stream control (H.245) varying with application
Advantages
» Distributed architecture
» Scalability
» Synergy with converged voice/data network architectures
• H.248/ MEGACO advantages for multimedia
–
–
–
–
Support for multiple terminations in a call context
Media descriptors for voice & video signals
Packages provide flexibility for extensions & customization
ITU-T SG 16 to standardize packages for H.324M support
12
Configuration of
3G-324M – H.323 Gateway
•Add/Delete H.245 termination
•Rough Resource Control
(max. no of audio/video termination)
Call
Control
*
MGC
Resource
Control
H.248
Bearer Control (H.245) in MG
H.225.0
•Control Audio/Video streams
•Based on H.245 signaling
•Follow the limitations set by MGC
MG
H.245
wireless
H.223
TDM
3G-324M
*
H.245 NT
H.323
LC
*
Audio NT
LC
*
Video NT
LC:Logical Channel
NT:Network Termination
IP
13
Other Configuration
Bearer Control (H.245) in MGC
Call
Control
H.245
MGC
Backhaul of H.245
*
H.225.0
*
H.245
Resource
Control
H.248
MG
H.245
wireless
H.223
TDM
3G-324M
H.323
LC
*
Audio NT
LC
*
Video NT
IP
LC:Logical Channel
NT:Network Termination
14
Complementary Standards
• Complementary standards from different organizations
enable:
– Wireless multimedia telephony
– Interworking between wireless multimedia and ITU-T H.3XX series
• ITU-T Standards
– Circuit switched standards such as H.324M
– Packet switched standards such as H.323
– Interworking standards such as H.246
• Joint IETF & ITU-T
– Media gateway control with MEGACO/ H.248
• IETF Standards
– IP/ packet standards such as SDP, RTP, & TCP
• 3GPP Standards
– Wireless standards such as 3G-324M & GSM-AMR speech
• ISO/ MPEG Standards
– Multimedia standards such as MPEG-4 video
15
Summary
• Emerging wireless multimedia applications
– Based on 3G-324M/ H.324M
– Supported as 3GPP circuit switched service
• Interworking to other networks
– Scenarios for H.3XX series terminals
– Scenarios for other terminals, such as SIP terminals
• Gateways to support interworking
– Flexible architecture with MGC & MG elements
– H.248/ MEGACO protocol for MGC to MG control
• Complementary standards help support interworking
scenarios
16
Multimedia Gateways
•
Back up slides and additional information
17
H.324M Transport Via IP Tunneling
•
3G-324M audiovisual call via IP-based core network
• Save the resource of MG and core network by multiplexing
audio and video stream into one connection
• Enable precise audio and video synchronization between GWs
Bearer Independent Call
Control
MGC
H.248
Circuit Switched
Radio Access
NW
MGC
IP-based Core NW
MG
H.248
MG
Circuit Switched
Radio Access
NW
IP tunneling of
3G-324M stream
3G-324M
18
3G-324M
Configuration of tunneling
gateway
•
Gateway for tunneling
*
Resource
MGC Control
MGC
H.248
MG
H.223
TDM
3G-324M
*
LC:Logical Channel
NT:Network
NT
MG
3G-324M
19