scope:

This Recommended Standard defines the Data Link Layer (Framing, Medium Access Control, Data Services, and Input/Output [I/O] Sublayers). The specifications for the protocol data units, framing, media access control, expedited and sequenced-controlled data transfer, timing service, I/O control, and the procedures for establishing and terminating a session between a caller and responder are defined in this document. The Coding and Synchronization Sublayer is defined in the separate CCSDS Recommended Standard entitled, Proximity-1 Space Link Protocol-Coding and Synchronization Sublayer (reference [5]). The Physical Layer is defined in the separate CCSDS Recommended Standard entitled, Proximity-1 Space Link Protocol-Physical Layer (reference [6]).

 This Recommended Standard does not specify a) individual implementations or products, b) implementation of service interfaces within real systems, c) the methods or technologies required to perform the procedures, or d) the management activities required to configure and control the protocol.

PURPOSE

The purpose of this Recommended Standard is to specify the Data Link Layer used with the Proximity-1 Data Link Coding and Synchronization Sublayer (reference [5]) and Physical Layer (reference [6]). Proximity space links are defined to be short-range, bi-directional, fixed or mobile radio links, generally used to communicate among probes, landers, rovers, orbiting constellations, and orbiting relays. These links are characterized by short time delays, moderate (not weak) signals, and short, independent sessions.

APPLICABILITY

This Recommended Standard applies to the creation of Agency standards and to future data communications over space links between CCSDS Agencies in cross-support situations. It applies also to internal Agency links where no cross support is required. It includes specification of the services and protocols for inter-Agency cross support. It is neither a specification of, nor a design for, systems that may be implemented for existing or future missions.

The Recommended Standard specified in this document is to be invoked through the normal standards programs of each CCSDS Agency and is applicable to those missions for which cross support based on capabilities described in this Recommended Standard is anticipated. Where mandatory capabilities are clearly indicated in sections of this Recommended Standard, they must be implemented when this document is used as a basis for cross support. Where options are allowed or implied, implementation of these options is subject to specific bilateral cross-support agreements between the Agencies involved.