3.1.5.9 Handling the Accept Header
The following sequence defines the required actions following the activation of the session:
The server MUST listen on transports according to information that was exchanged with the client in earlier steps of the protocol.
The client MUST attempt to connect to the server on all the transports that the server is listening on.
The server chooses the best connection and accepts it.
On connection establishment, the client MUST send an Accept Header (section 2.2.1) to the server.
On receipt of the Accept Header, the server MUST validate the SessionID from the Accept Header by comparing it to the ReplyChannelID that it received from the client in the Session Activation message (section 2.2.11).
If the IDs match, the server MUST send the Accept Header back to the client. If the IDs do not match, the server MUST abort the connection.
The client MUST validate the Accept Header received from the server by comparing it to the Accept Header it sent before. If the Accept Headers match, the negotiation is complete; otherwise, the client MUST abort the connection.