Multimedia Gateways

1
Multimedia Gateways H.248/ MEGACO
ITU Workshop on IP Networking
MEDIACOM-2004 April 26, 2001 Presented
by- Clifford Sayre, Lucent Technologies

2
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)

3
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

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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)

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Bearers of IMT-2000 and the Type of Services
Bearers
Services to be Covered
Type of Bearers
Voice Communication
Voice
Circuit Switched
Non-specified Digital
Internet
Audio/Video Communication
Video phone (3GPP 3G-324M)
Packet
Internet
Packet Switched

• 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

6
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
Packet Switched Mobile Network
MGC
Circuit Switched Mobile NW
H.248
MT (PS) (SIP/H.323)
3G-324M
MG
Internet
H.323/SIP
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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 _at_ 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 Implementors Guide

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Building Blocks of 3G-324M/ H.324M

• H.223 multiplexed bitstream is mapped onto
  digital channel
• Bearer control messages are delivered as in-band
  data
• Modem/Mode negotiation is not applied

Out-band
Call Control
In-band
Bearer Control H.245
Wireless Network
Wireless Network I/F
Audio CODEC AMR
H.223 Annex B
Video CODEC H.263/MPEG-4
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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

H.323
3G-324M
Call Control
Q.931/H.225.0
TCP
Bearer Control H.245
Bearer Control H.245
Wireless Network I/F
IP
Audio CODEC AMR
Audio CODEC
H.223 Annex B
RTP/UDP
Video CODEC H.263/MPEG-4
Video CODEC
10
Interworking with SIP

• Interworking with SIP requires
• Mapping of Call Control /Bearer Control Signaling
  to SIP/SDP
• Conversion of Media Transport Format
• Media Transcoding

SIP
3G-324M
Call Control
SIP/SDP
TCP or UDP
Bearer Control H.245
Wireless Network I/F
IP
Audio CODEC AMR
Audio CODEC
H.223 Annex B
RTP/UDP
Video CODEC H.263/MPEG-4
Video CODEC
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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)

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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

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Configuration of 3G-324M H.323 Gateway

• Add/Delete H.245 termination
• Rough Resource Control
• (max. no of audio/video termination)

Bearer Control (H.245) in MG
MGC
Call Control
H.225.0

Resource Control

• Control Audio/Video streams
• Based on H.245 signaling
• Follow the limitations set by MGC

H.248
MG
H.245
H.245
NT

H.323 IP
3G-324M wireless
TDM
H.223
LC
Audio
NT

LC
Video
NT

LCLogical Channel NTNetwork Termination
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Other Configuration
Bearer Control (H.245) in MGC
MGC
Call Control
H.225.0


H.245
H.245
Resource Control
Backhaul of H.245
H.248
MG
H.245
H.323 IP
3G-324M wireless
TDM
H.223
LC
Audio
NT

LC
Video
NT

LCLogical Channel NTNetwork Termination
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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

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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

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Multimedia Gateways

• Back up slides and additional information

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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
MGC
IP-based Core NW
H.248
H.248
Circuit Switched Radio Access NW
Circuit Switched Radio Access NW
MG
MG
IP tunneling of 3G-324M stream
3G-324M
3G-324M
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Configuration of tunneling gateway

• Gateway for tunneling

MGC
MGC

Resource Control
H.248
MG
MG
NT
3G-324M
3G-324M
TDM
H.223

LCLogical Channel NTNetwork