Mission Operations Reference Model. Draft ... - CCSDS

DRAFT RECOMMENDED PRACTICE FOR MISSION OPERATIONS REFERENCE MODELThe basic outline of this sequence from the high-level sequence (figure 4-2) is that theTransport layer receives message from the MAL and passes them to the relevant destination.a) The MAL submits the message to the Transport layer using the layer’s abstractservice interface.b) The Transport layer checks the contents of that message to ensure that it contains allthe required aspects. If it fails these checks, then an error is returned to the MAL.c) If the message is from a provider (determined by examining the interaction patternstage fields of the message), then the error message is also transmitted to thetransaction source.d) If there was an error, then the sequence ends at this point.e) The Transport layer then encodes the message and digitally signs the encodingmessage, if applicable. The need for a digital signature and the method used isdeployment specific.f) If the digital signing component rejects the message, then it returns an error using animplementation specific mechanism. The Transport layer creates the relevant AccessControl error message and passes this back to the MAL as a transport failure message.g) There is no need to send the error to the transaction source if the message is from aprovider, as the signing process has failed, and therefore it would automatically berejected by the destination transport.h) If there was an error, then the sequence ends at this point.i) The Transport layer then opens a connection and transmits the encoded message tothe destination. The actual process at this point is transport-specific.j) If the Transport encounters an error during its attempt to transmit the message, then itreturns an error to the MAL. The sequence then ends.k) If there are no issues during sending by the Transport it returns a success message tothe MAL.CCSDS 520.1-R-1 Page 4-17 October 2009