Logical Channel Proposal in H.323 Fast Connect - Exam 400-051: CCIE Collaboration

Logical Channel Proposal

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What is the name of the logical channel proposal that is transmitted from the called entity to the calling entity in H.323 Fast Connect?



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A. B. C. D. E.


Unlike the OpenLogicalChannel request used by H.323 for video uni-directional logical channels, the request used by H.324 for opening video bi-directional logical channels specifies the temporalSpatialTradeOff Capability in both the forward and reverse directions--in the forwardLogicalChannelParameters.dataTypeandreverseLogicalChannelParameters.dataType components, respectively.

The semantics of temporalSpatialTradeOffCapability used in forward LogicalChannelParameters.dataType is described in the previous section.

The semantics for its presence in the reverse direction is described in this section.

In H.323 Fast Connect, when a call is initiated, the calling entity sends a logical channel proposal to the called entity. The called entity then responds with its own logical channel proposal. This exchange of proposals is called Fast Connect because it reduces the amount of time required to establish the call.

The logical channel proposal sent by the called entity to the calling entity is known as the "backward logical channel." This proposal specifies the media capabilities that the called endpoint can support for the call.

The backward logical channel proposal includes information such as the codecs that the called endpoint supports, the audio and video capabilities, and the bandwidth that is available. This proposal is sent from the called endpoint to the calling endpoint to inform it of the media capabilities that can be used for the call.

The calling endpoint can then choose from the available options and respond with its own logical channel proposal, called the "forward logical channel." The forward logical channel proposal specifies the media capabilities that the calling endpoint can support for the call.

The logical channel proposals are an essential part of the H.323 protocol, as they allow the endpoints to negotiate the media capabilities that they will use for the call. By using Fast Connect and exchanging logical channel proposals, the endpoints can establish a call quickly and efficiently, using the best media capabilities available to them.

In summary, the correct answer to the question is B. Backward Logical Channel.