IMG 1010 - H245 Tunneling
Overview
The H.245 protocol is a media control protocol that is a part of H.323 protocol suite. The H.245 protocol is used primarily to negotiate master-slave relationship between communicating endpoints. These endpoints exchange terminal capabilities and logical channel manipulations (open, close, modify).
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The H.245 messages are encapsulated into H.225 messages within a special header called H245Control as described by ASN.1. The H245Control header can be added to any message except initial Setup message. However, if there are no other messages to be shipped out from an endpoint, a designated Facility message is used. (H.323 V2 accepts and defines Empty Facility message) as transport vehicle to carry on H.245 contents.