Space Link Extension - Service Management - CCSDS

DRAFT RECOMMENDED STANDARD FOR SPACE LINK EXTENSION SERVICE MANAGEMENT
If data privacy and data integrity are required for the exchange of documents, these
capabilities are also expected to be provided by the underlying communication service.
NOTES
1 The format of the identification of the Source and Destination within the underlying
communication technology is dependent upon that technology.
2 References [18]–[20] specify the security mechanisms for authentication, data
privacy, and data integrity that are recommended for use when the SLE-SM
documents are encoded as XML documents.
The underlying communication service supplies the identity of the Source of the document to
the SLE-SM document exchange protocol, which uses that authenticated identity for the
purposes of (a) verifying the authority of the Source to issue documents in the context of the
Service Agreement that is identified in the message, and (b) allowing the document exchange
protocol and the SLE-SM applications that use it to know where to send responses, if
necessary.
The underlying communication service provides the ability for an SLE-SM entity to send
documents to two logically separate ports on a peer SLE-SM entity. As described in 3.3,
these logically separate ports, the SLE-SM message set port and the SLE-SM exception
response port, are used by the document exchange protocol to separate SLE-SM operation
message traffic from protocol exception reporting traffic.
NOTES
1 The realization of the separate logical ports is dependent on the technology used by
the communication service. For example, it could be multiple TCP sockets, multiple
URLs, or the use of different Subject lines in email messages.
2 Existing standard communication protocols (e.g., TCP, HTTP), middleware (SOAP),
etc., may not meet all of the requirements for the underlying communication protocol
‘off the shelf.’ It may be necessary to augment such existing standard services with
additional adaptation or ‘shim’ capabilities.
The preservation of sequencing among messages transmitted at different times is not
assumed to be a characteristic of the underlying communication service. As defined in 3.3,
the SLE-SM document exchange protocol provides a capability to preserve required
sequencing among multiple SLE-SM invocation messages sent concurrently by allowing
those invocation messages to be sent within the same document. This same-document
sequencing capability is sufficient to meet the requirements of the SLE-SM document
exchange protocol and the operational procedures that use it, as specified herein. However,
the SLE-SM document exchange protocol does not guarantee that messages in two different
documents will be received by the Destination in the order that those messages were
originally generated by the Source. If a real operational environment in which SLE-SM is
applied has requirements that sequencing be preserved among messages across multiple
CCSDS 910.11-R-2 Page 3-3 March 2008