Validating Incoming Messages
Once the message is captured by a driver session, it is passed to the entry point in the protocol message flow configured for reception.
Once in the protocol message flow, the incoming protocol message goes through several modules. Commonly the first module frames the incoming message. Lets call it a framer. The framer may need to decode parts of the incoming message to determine whether the message is valid according to some syntax. This does not mean it must decode the request information itself, but typically just some envelope data.
This task may be performed at a lower level by another module in the protocol message flow while decoding a frame too.
For example, an incoming message may contain a message header as well as the message itself. The parser might only accept messages with a specific header format, and also validate the header contents. If the parser cannot validate an incoming message, it raises an alarm.