Call Proceeding; Capability Negotiation; Complete Release - HP FlexNetwork MSR Series Configuration Manual

Call setup
After receiving the ACF message from the gatekeeper, the calling endpoint sends call signaling to
set up a call. In a direct call signaling for example, the calling endpoint first sends a Setup message
to the called endpoint requesting for a connection.

Call proceeding

After receiving the Setup message, the called endpoint replies with a Call Proceeding message.
However, it might not send this message.
Alerting
Then the called endpoint might send an Alerting message to the calling endpoint, indicating its status
(for example, ringing). The endpoint might not send this message.
Connection
If the called endpoint accepts the call, it must send a Connect message.

Capability negotiation

After the calling endpoint receives the connect message, an H.245 control signaling channel is
established to control the media session between the endpoints. First, the two endpoints exchange
information on their capabilities, such as media format.
Opening/closing logical channels
The two endpoints open one or more logical channels between them for transporting media streams.
(The logical channels are specified by IP address plus port number.)
These channels are closed when the communication is over.

Complete release

Finally, either endpoint in communication can release resources by sending a Release Complete
message.
Disconnection
The endpoints each send a Disconnect_Request (DRQ) to their own gatekeepers, which will confirm
or reject the request. The gatekeepers, however, might send a DRQ to the endpoints. In this case,
the endpoints can only confirm the request.
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