Brackets
This section primarily describes the bracket protocols between the local node and an application for a session supporting half-duplex flip-flop with brackets.
The local node enforces no bracket protocols for full-duplex sessions. Therefore, messages with begin bracket (BB) are not presented as Status-Control(BID) messages, and there are no Status-Session(BETB) messages.
The management of this protocol for a generalized application is complex, and there is a significant amount of code in the local node to simplify the application's perception of the protocol. An application is only aware of two states:
In-bracket
Between-bracket
The local node, in addition to the states of in-bracket and between-bracket, maintains transient states with a large state transition matrix, or finite-state machine, governing the half-session's state at a particular time.