3.1.5 Processing Events and Sequencing Rules
When a message is received, the implementation MUST verify that the message conforms to the syntax specified in section 2.2.
If the message does not conform to the syntax specified in section 2.2, the following processing steps are performed:
The implementation MUST abort further processing.
The implementation MAY<4> return an error to the higher-layer application protocol. Otherwise, it MUST fail silently.