Session Control Protocol definition
Many internet applications (FTP, GOPHER, and HTTP) establish a new Transmission Control Protocol connection for each transaction. This approach is not very efficient since it requires initiating a connection for every request. That’s even when multiple requests are sent to the same server.
The Session Control Protocol (SCP) addresses this inefficiency. It allows multiple exchanges to occur over a single TCP connection.
- Session ID Allocation: Each session is assigned a unique identifier. IDs below 1024 are reserved, with client-allocated IDs being even and server-allocated IDs being odd.
- Session Establishment: A session starts by sending a message with the SYN bit set on that channel.
- Graceful Release: Sessions are closed by sending a message with the FIN bit. Connections can be ended independently at each end.
- Disgraceful Release: A session can be abruptly terminated using a message with the RST bit. All pending data for that session is discarded.
- Message Boundaries: These are defined by sending a message with the PUSH bit set, with the boundary including the final octet of this message.