OpenH323

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OpenH323

• Open source internet videoconferencing

Jeremy Medow Presented to Dr. Dennis Anderson
and team 6/10/02
www.openh323.org
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OpenH323
General Information
Protocol Language Codecs
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OpenH323

• Based on the H.323 protocol
• Same protocol used by
• Microsoft Netmeeting
• Many standalone videoconferencing units
• Developed by the ITU (www.itu.int)
• Most recent accepted protocol

Protocol
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OpenH323

• Written in C
• Entirely open source
• Any or all of the program can be used freely
• Code can be downloaded from http//www.openh323.or
  g/code.html.
• If the openh323 library is used strictly as a
  library, a commercial product can be produced

Language
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OpenH323

• Codecs
• Supports G.711 and GSM audio codecs
• Supports H.261 video codec

Codecs
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OpenH323
Capabilities
Programs Interfaces Platforms
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OpenH323

• OpenPhone, OhPhone
• Endpoint clients
• OpenMCU
• Multipoint control unit
• OpenGK
• Gatekeeper
• Others
• Answering machine, gateway, etc.

Programs
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OpenH323

• GUI
• OpenPhone has a graphical user interface
• More user friendly
• Command Line
• OhPhone has a command line interface
• More flexible, powerful

Interfaces
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OpenH323

• GUI client for Windows
• OpenPhone
• Command line client for Windows, Linux
• OhPhone
• MCU, Gateway for all platforms
• OpenMCU, PSTNGw

Platforms
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OpenH323
H.323 Details
Architecture Multipoint Streams Channels
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OpenH323

• Terminals
• Client endpoints interface, etc.
• Gateways (optional)
• Translation, call setup
• Gatekeepers
• Call control, Bandwidth management, routing
• Multipoint Control Units
• Manage 3 endpoint communications

Architecture
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OpenH323

• MCU is actually two components
• MC (Multipoint Controller)
• Deals with connection protocols
• Chooses stream (audio/video/data) destinations
• MP (Multipoint Processor)
• Mixes/switches streams
• Transmits streams to appropriate destinations
• MCU can be standalone or embedded within endpoints

Multipoint
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OpenH323

• Types of multipoint control
• Centralized
• All streams are sent to MCU
• MC manages streams
• MP mixes, distributes streams
• Decentralized
• Audio, Video are multicast to, from all endpoints
• Data, call control information sent to MCU
• Hybrid
• Mix of Centralized and Decentralized

Multipoint (contd)
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OpenH323

• Control
• H.245 Capabilities, channel management
• Q.931 Establishes connections
• RAS Bandwidth changes, status, disengage
• Audio
• G.771 Voice compression
• Video
• H.261 Video codec (H.263 possible)
• Data (Whiteboard, data sharing, file transfer)
• T.120 Can be used by endpoints, mixed by MCU

Streams
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OpenH323

• Two channels
• Reliable (TCP) Accurate
• Control channel (H.245)
• T.120 Data channel
• Call signaling channel (Q.931)
• Unreliable (UDP) Faster
• Audio stream
• Video stream
• RAS channel (only with gatekeeper)

Channels
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OpenH323
More Information
OpenH323 H.323 details
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OpenH323

• www.openh323.org
• Information on OpenH323
• Capabilities, updates
• Licensing details
• Downloads
• Source code (C)
• Executables
• Links
• Information on H.323

OpenH323
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OpenH323

• www.packetizer.com/iptel/h323
• Papers Presentations
• An H.323 primer
• Multipoint information
• General information
• Links

H.323 details
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OpenH323

• Open source internet videoconferencing

www.openh323.org