1 segmentation layer sending end service

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Unformatted text preview: ments CCSDS 202.0-B-2 Page B-3 CCSDS HISTORICAL DOCUMENT November 1992 CCSDS HISTORICAL DOCUMENT CCSDS RECOMMENDATION FOR TELECOMMAND: DATA ROUTING SERVICE B-2.1 Segmentation Layer: Sending End Service Specification (1) INPUTS From the Packetization layer or other layer above: (a) Transportable TC User Data Units (e.g., TC Packets) which are to be routed to the spacecraft. The length of the TC User Data Unit is unconstrained; however, if they are TC Packets, then each will have a maximum length of 65542 octets. (b) Control instructions which are required in order to transfer the user data structures to the spacecraft. Those control instructions specifying delivery priority are read and processed by the Segmentation layer and establish the multiplexing hierarchy within this layer. Other control instructions (e.g., directives to abort specific commands) are passed through to the layer below. NOTE: The abstract content and concrete format of the control instructions are not presently specified and remain an item for potential future extension. From the receiving end of the Segmentation layer: None. From the Transfer layer below: (c) (2) Information describing the status of transfer of TC Frame Data Units through a given Virtual Channel. OUTPUTS To the Packetization layer or other layer above: (a) Information describing the status of transfer of TC User Data Units. To the receiving end of the Segmentation layer: None. CCSDS 202.0-B-2 Page B-4 CCSDS HISTORICAL DOCUMENT November 1992 CCSDS HISTORICAL DOCUMENT CCSDS RECOMMENDATION FOR TELECOMMAND: DATA ROUTING SERVICE To the Transfer layer below: (b) (c) (3) User data structures which have been formed into TC Frame Data Units. Control instructions, possibly passed through from the layer above. INTERNAL FUNCTIONS (a) (b) Breaks or aggregates the TC User Data Units into pieces which are compatible with insertion into the data field of the TC Frame Data Unit. (c) Optionally labels each piece with sequence control and MAP identification inf...
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This document was uploaded on 03/06/2014.

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