3.1 Client Details

Unless specified otherwise, the protocol reports the occurrence of an error to the higher layer, stops all timers, and stops processing further messages. Possible errors include the following: failure to connect to the server, the connection to the server is unexpectedly closed, the response to a request indicates an error, the Reason field in the $E or $C packets indicates an error, a malformed packet is received (such as a $D packet not adhering to the syntax for packets of that type), or an unexpected packet (such as receiving a $P packet when waiting for a $H packet) is received.

Unless specified otherwise, the client role of the protocol always provides the value of the Higher-Layer-ID variable in the Abstract Data Model to the higher layer when it invokes the higher layer.