Presentation of H323 protocol
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H.323 is a standard for multimedia communications over packet-based networks. It defines protocols for real-time audio, video and data communications between endpoints such as terminals, gateways and multipoint control units. As an umbrella standard, H.323 references other protocols for functions like call signaling, bandwidth negotiation and transmission of audio and video data. H.323 provides scalable and flexible multimedia communication capabilities and has been widely adopted for voice and video conferencing over both internet and private networks.
Presentation of H323 protocol
- 2. Mahbuba Monzur Mou 172-15-9891 Mahabubur Rahman Pollob 172-15-9877 Tanzimul Hasib 172-15-9895 Md. Taiseen Azam 171-15-9142
- 3. H.323 is not actually a protocol that you'll see on the network it's what we call an Umbrella Protocol & it is from the International Telecommunications Union Telecoms sector, so it actually includes a bunch of sub protocol’s. What is H.323?
- 4. H323 intro : o H.323 is a multimedia conferencing protocol, which includes voice, video & data conferencing for use over Packet-switched networks. o So, H.323 is a standard specified for Packet-based Multimedia Communications Systems by ITU-T. o H.323 suite is an ´Umbrella´ standard, references to other standards and ITU recommendations.
- 5. Local Area Network The 1st version of H.323 protocol was published in 1996 & was “designed for Local Area Networks”
- 6. The first thing companies tried to do was use H.323 in Wide Area Networks, large private VoIP networks & the Internet ◦ Output result : it worked very well
- 7. H.323 version 4 was approved November 17, 2000 & brings a number of enhancements to H.323. Areas of focus include: ◦ Scalability ◦ Services ◦ “Must Have” Features ◦ Generic Extensibility Framework
- 8. H.323 Standards Network Non-guaranteed Bandwidth packet-switched networks (e.g. IP) Video H.261, H.263 Audio G.711, G.722, G.728, G.723, G.729 Call signaling & media packetisation H.225 Call Control H.245 Multipoint H.323 Data T.120
- 9. Elements of an H.323 System 1. Terminals 2. Multipoint Control Units (MCUs) 3. Gateways 4. Gatekeeper 5. Border Elements Referred to as “endpoints”
- 10. Terminals o Telephones o Video phones o IVR devices o Voicemail Systems o “Soft phones” (e.g. NetMeeting®) T
- 11. Multipoint Control Units: (MCUs) Responsible for managing multipoint conferences (two or more endpoints engaged in a conference) The MCU contains a Multipoint Controller (MC) that manages the call signaling & may optionally have Multipoint Processors (MPs) to handle media mixing, switching or other media processing MCU MC MP
- 12. Gateways The Gateway is composed of a “Media Gateway Controller” (MGC) & a “Media Gateway” (MG), which may co-exist or exist separately o The MGC handles call signaling & non-media-related functions o The MG handles the media GW
- 13. Gatekeeper The Gatekeeper is an optional component in the H.323 system which is used for admission control & address resolution The gatekeeper may allow calls to be placed directly between endpoints or it may route the call signaling through itself. GK
- 14. Border Elements which are often co-located with a Gatekeeper, exchange addressing information & participate in call authorization between administrative domains It may aggregate address information to reduce the volume of routing information passed through the network BE
- 15. Zone GK GW MCU T There is no imposed limit on the number or types of devices in a zone A single Gatekeeper & all of the devices connected to it The physical location of the Gatekeeper with respect to its endpoints is immaterial
- 16. Administrative Domain There is no specified limit on the number of Zones within an Administrative Domain A collection of Zones that are under a single administrative control (e.g. a service provider or enterprise network)
- 17. Topology with RAS GK GK T T MCU GW GK GK GK GWGWGWGW GK Hierarchical Gatekeeper topology is widely used, but explicitly discussed in H.323
- 18. Topology with Annex G/H.225.0 BE GK GK T T MCU GW BE GK GK GWGWGWGW
- 22. Registration, Admission & Status - RAS (cont) T GK RRQ RCF ARQ (endpoint is registered) ACF (endpoint may place call) DRQ DCF (call has terminated)
- 23. GW Basic Call Setup Signaling GW Setup Call Proceeding Progress Alerting Connect CONNECTED Release Complete Optional
- 24. RAS & H.225.0 Call Signaling GK GW GK GW 1. ARQ 2. LRQ 3. LCF 4. ACF 5. Setup 6. ARQ 7. ACF 8. Connect
- 25. H.323 Call Signalling Model Direct Call Model Gatekeeper Optional Gatekeeper Router Call Model
- 27. Gatekeeper Router Call Model
- 28. Comments on H.323 H.323 is scalable H.323 allows the use of multiple codecs H.323 is a very complex system with all of kinds of features for multimedia communications H.323 is a proven technology used in large networks. It has excellent integration with PSTN. Multimedia conferencing shows the real potential for H.323 used in multimedia communication
- 29. H.323 is organized around four major facilities: (a) terminals, (b) Gateways, (c) Gatekeeper & (d) MCUs A principal technology for the transmission of real-time audio, video, & data communication over packet-based networks Multipoint & point-to-point sessions. A rich & complex specification Scalable, reliable, flexible system, Supplementary services & new features are powerful Conclusions
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