1. Onno W. Purbo Onno@indo.net.id
H.323
Onno W. Purbo

2. References
Dr. Andreas Steffen, Komunikationsysteme

3. ITU-T H.323

4. ITU-T Multimedia Comm

5. H.323 Network Components

6. H.323 Gateways Functions .. Physical Interface LAN  PSTN Call setup
POTS (analog)
ISDN (digital)
Call setup
Setup & release call both LAN & PSTN
Translation of Transmission Multiplex Formats
H to H.221 / H.223

7. H.323 Gateways Functions .. Translation of System Control Protocol
H.245 to H.242
Audio / Video Transcoding
Translation among audio codecs, conversion to analog voice.
Translation among video codecs (if terminal do not support negotiation)

8. H.323 gatekeepers

9. Registration, Admission and Status ..

10. Registration, Admission and Status (RAS)
RAS defined in ITU-T H.225.0
RAS is used between H.323 endpoint and the gatekeeper of H.323 zone they are assigned to.

11. Automatic Gatekeeper Discovery

12. Endpoint Registration

13. Endpoint Unregistration

14. Endpoint Location

15. Endpoint Admission To Network

16. H.323 Gatekeeper Functionality
Address Registration & Translation
RRQ/RCF/RRJ and LRQ/LCF/LRJ messages.
Translation of alias addresses to transport addresses.
Admission Control
ARQ/ACF/ARJ messages.
Authorization of LAN access (call authorization, bandwidth).
Bandwidth Control and Management
BRQ/BCF/BRJ messages.
Dynamic change of requested and available bandwidth.

17. H.323 call setup & control