3.3.3.2 DVC Initialization
A DVC server manager initializes a channel by exchanging Create PDUs with a DVC client manager.
Two different Create PDUs are used to open a channel:
A DVC server manager creates a channel in response to a request by an application running on the TS server to create a channel to a listener running on the TS client. The server creates a channel for the requesting application using a listener name. The server sends the ChannelId and the listener name to the DVC client manager. A version 2 server also sends the channel priority to the DVC client manager. The server maintains this ChannelId for the life of the channel.
The DVC client manager responds to the DVC server manager with a DYNVC_CREATE_RSP (section 2.2.2.2) PDU indicating the channel creation status. Any positive or zero value indicates success. A negative value indicates failure.
On failure, the server DVC manager MAY<12> send a DYNVC_CLOSE (section 2.2.4) PDU for the failed channel. The listener name is only used at channel initialization. After the channel is initialized, all data is sent referencing the ChannelId.
The Channel ID MUST be unique within a static virtual channel session. The server DVC manager SHOULD reuse a Channel ID if the channel creation failed, or if the channel has been closed.
There is no processing specified by the Remote Desktop Protocol: Dynamic Virtual Channel Extension for a priority class.