Open H 323 Open source internet videoconferencing Jeremy

Open. H 323 Open source internet videoconferencing Jeremy Medow Presented to: Dr. Dennis Anderson and team 6/10/02 www. openh 323. org

Open. H 323 General Information Protocol Language Codecs

Open. H 323 • 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

Open. H 323 • Written in C++ – Entirely open source • Any or all of the program can be used freely – Code can be downloaded from http: //www. openh 323. org/code. html. – If the openh 323 library is used strictly as a library, a commercial product can be produced Language

Open. H 323 • Codecs – Supports G. 711 and GSM audio codecs – Supports H. 261 video codec Codecs

Open. H 323 Capabilities Programs Interfaces Platforms

Open. H 323 • Open. Phone, Oh. Phone – Endpoint clients • Open. MCU – Multipoint control unit • Open. GK – Gatekeeper • Others – Answering machine, gateway, etc. Programs

Open. H 323 • GUI – Open. Phone has a graphical user interface • More user friendly • Command Line – Oh. Phone has a command line interface • More flexible, powerful Interfaces

Open. H 323 • GUI client for Windows – Open. Phone • Command line client for Windows, Linux – Oh. Phone • MCU, Gateway for all platforms – Open. MCU, PSTNGw Platforms

Open. H 323 H. 323 Details Architecture Multipoint Streams Channels

Open. H 323 • Terminals – Client endpoints: interface, etc. • Gateways (optional) – Translation, call setup • Gatekeepers – Call control, Bandwidth management, routing • Multipoint Control Units – Manage 3+ endpoint communications Architecture

Open. H 323 • 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

Open. H 323 • 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 (cont’d)

Open. H 323 • 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

Open. H 323 • 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

Open. H 323 More Information Open. H 323 H. 323 details

Open. H 323 • www. openh 323. org – Information on Open. H 323 • Capabilities, updates • Licensing details – Downloads • Source code (C++) • Executables – Links • Information on H. 323 Open. H 323

Open. H 323 • www. packetizer. com/iptel/h 323 – Papers & Presentations • An H. 323 primer • Multipoint information – General information – Links H. 323 details

Open. H 323 Open source internet videoconferencing www. openh 323. org