Mission Operations Reference Model. Draft ... - CCSDS

DRAFT RECOMMENDED PRACTICE FOR MISSION OPERATIONS REFERENCE MODEL4.2.2 HIGH-LEVEL SENDING SEQUENCEThe high-level sending sequence down the stack is shown in figure 4-2.Consumer/ProviderApplicationMO Service Layer MAL Access Control Transport LayerInvoke service operationSubmit messageCheckTransmit messageThe sequence is as follows:Figure 4-2: High-Level Sending Sequencea) The Application invokes the relevant service operation provided by the MO ServiceLayer. This operation may be the start of a message exchange by a service consumer(do some operation) or by a service provider in response to an existing operationrequest (here is the result).b) The MO Service Layer converts that operation invocation to a MAL message andpasses that to the MAL using its abstract service interface.c) The MAL first checks that the message may be sent using the Access Controlcomponent. The rules of the Access Control component are deployment specific, it isa deployment decision as to what must be checked before a message is sent.d) Finally the message is passed to the Transport layer for encoding and transmission tothe destination.CCSDS 520.1-R-1 Page 4-3 October 2009