H.245 Information Exchanged in H.323 Fast Connect

B.

With the standard H.245 negotiation, the two endpoints need three round-trips before they agree on the parameters of the audio/video channels (1

master/slave voting, 2

terminal capability set exchange, and finally, 3

opening the logical channels)

In certain situations and especially with high-latency network links, this can last too long and users will notice the delay.

In H.323 Fast Connect, the H.245 information that is exchanged within H.225 messages includes the Terminal Capability Set and the Open Logical Channel.

The Terminal Capability Set is a collection of capabilities that are supported by an endpoint. These capabilities may include audio and video codecs, data transfer protocols, and other features that enable communication between endpoints. During a call setup in H.323 Fast Connect, the Terminal Capability Set is exchanged between the endpoints to determine which codecs and protocols are compatible with each other. This information is used to negotiate the communication parameters for the call.

The Open Logical Channel is a mechanism that is used to establish a data stream between endpoints. This channel is used to transmit audio, video, or data during a call. In H.323 Fast Connect, the Open Logical Channel is established during the call setup process. The endpoint that initiates the call sends an Open Logical Channel message to the remote endpoint, which responds with a message indicating that the channel has been opened. This channel is then used to transmit the audio, video, or data during the call.

The other options listed in the question are not exchanged within H.225 messages in H.323 Fast Connect. Master-Slave Determination is used in H.245 messages to determine which endpoint will control the call setup process. Call Setup and Call Progress are also not exchanged within H.225 messages, but are instead part of the overall call setup process in H.323.