H.323

Onno W. PurboOnno@indo.net.id

Referensi .. Dr. Andreas Steffen,

Komunikationsysteme

ITU-T H.323

ITU-T Multimedia Comm

H.323 Network Components

H.323 Gateways Functions .. Physical Interface LAN PSTN

POTS (analog) ISDN (digital)

Call setup Setup & release call both LAN & PSTN

Translation of Transmission Multiplex Formats H.225.0 to H.221 / H.223

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)

H.323 gatekeepers

Registration, Admission and Status ..

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.

Automatic Gatekeeper Discovery

Endpoint Registration

Endpoint Unregistration

Endpoint Location

Endpoint Admission To Network

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.

H.323 Gatekeeper Functionality Call Authorization, Control and

Management Access restrictions, upper limits on

simultaneous calls. Zone Management

Gatekeepers provide above services for terminals, gateways, and MCUs registered within their zone of control.

H.323 call setup & control Call Signaling Channel (Q.631)

Q.631 call signaling channel is defined in ITU-T H.225.0.

Carried over TCP port 1720. Control Channel (H.245)

As part of Q.931 setup, TCP port for H.245 dynamically allocated.

Destination TCP port in usually in Connect Msg called party.

Negotiation of common capability.

Gatekeeper-routed call signaling.

Direct endpoint call signaling.

Gatekeeper-routed Control Channel.

Direct Control Channel Connection.

H.245 Capability Exchange

Channel Multiplexing

H.225.0 Channel Multiplexing

Transport of Logical Channel