3.2.5.1 General Packet Validation

The CBCP messages MUST comprise the basic fields; namely, Code, Identifier, and Length. If the message received is less than 4 bytes in size, which means that not all of these fields are present, the message MUST be dropped silently and ignored. If the Code of the CBCP message received is not 2 (specifying the Callback Response message), the message MUST be dropped silently and ignored.

When messages are dropped silently and ignored, state MUST NOT change.