Space Link Extension - Service Management - CCSDS

DRAFT RECOMMENDED STANDARD FOR SPACE LINK EXTENSION SERVICE MANAGEMENT
SLE-SM
Operation
Procedure
W
(2 Phase)
two-phase operation
procedure pattern
SLE-SM
Operation
Procedure
X
(3 Phase)
SLE-SM
Operation
Procedure
Y
(3 Phase)
three-phase operation
procedure pattern
SLE-SM
Operation
Procedure
Z
(Notified)
notified operation
procedure pattern
invocations
and returns
notifications
and confirmations
SLE-SM document exchange protocol
SLE-SM
message sets
authenticated, recognized
source identification
SLE-SM exception
responses
underlying communication service
Figure 3-1: Relationship among SLE-SM Operation Procedures, Document
Exchange Protocol, and Underlying Communication Service
3.2 UNDERLYING COMMUNICATION SERVICE
The underlying communication service is used to exchange SLE-SM documents among SLE-
SM application entities. The underlying communication service maintains the relationship
among each SLE-SM application entity and the identification of the ports through which it
communicates with other SLE-SM application entities. The underlying communication
service establishes and maintains the communication association between each pair of
communication entities.
NOTE – The underlying communication service may be built upon connectionless
protocols such as UDP or SMTP, but if so then the underlying communication
service must include a ‘sublayer’ that maintains the association. Alternatively, if
no such automated association maintenance capability is provided by the
underlying communication service itself, the communications association has to
be established, maintained, and terminated by manually executed procedures.
At a minimum, the underlying communication service must authenticate the Source of each
document carried by the service and validate that the Source is recognized by the Destination
as an entity that is permitted to send documents to it. As used in this Recommended
Standard, Source and Destination refer to the communicating entities as they are known to
the underlying communication service. Documents for which the Source cannot be
authenticated and recognized are dropped by the communication service. There is no
requirement on the underlying communication service to notify the Source when a document
is dropped because of failure to authenticate the Source or recognize it on behalf of the
intended Destination. Only when the underlying communication service authenticates the
Source and recognizes it as a legitimate Source for the intended Destination does it deliver
the document to the Destination.
CCSDS 910.11-R-2 Page 3-2 March 2008