The remainder of this section discusses data frames. When a message is segmented and sent as several frames, those frames must be sent sequentially, without any intervening frames from other messages on the same channel. Note that the sequence number is advanced for each frame sent on the channel, and is independent of the messages sent in those frames. If a frame is poorly-formed, then the session is terminated without generating a response, and it is recommended that a diagnostic entry be logged. The frame payload consists of zero or more octets.
Every payload octet sent in each direction on a channel has an associated sequence number.
Accordingly, when receiving a frame if the sequence number isn't the expected value for this channel, then the BEEP peers have lost synchronization, then the session is terminated without generating a response, and it is recommended that a diagnostic entry be logged. When receiving a frame, if the characters immediately following the payload don't correspond to a trailer, then the session is terminated without generating a response, and it is recommended that a diagnostic entry be logged. The semantics of each message is channel-specific. If a poorly-formed reply is received on channel zero, the session is terminated without generating a response, and it is recommended that a diagnostic entry be logged. If a poorly-formed reply is received on another channel, then the channel must be closed using the procedure in Section 2.3.1.3.