D multiplexes tc frame data units from different maps

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Unformatted text preview: ormation to create a TC Segment. The TC Segment or the piece from (b), if the Segment Header is not used, becomes the TC Frame Data Unit. (d) Multiplexes TC Frame Data Units from different MAPs together onto one Virtual Channel for flow control purposes. (e) B-2.2 Assigns individual TC User Data Units to particular Multiplexer Access Points (MAPs) for routing to the spacecraft through a Virtual Channel (VC) provided by the Transfer layer. Monitors the process of transferring TC Frame Data Units through Virtual Channels by the layers below, and maintains cognizance of the status and availability of particular Virtual Channels. Segmentation Layer: Receiving End Service Specification (1) INPUTS From the Packetization layer or other layer above: (a) Information concerning the ability of the higher layer to accept more data. From the sending end of the Segmentation layer: None. From the Transfer layer below: (b) TC Frame Data Units in sequence and complete, without omission or duplication (if sent as Type-A Frames). CCSDS 202.0-B-2 Page B-5 CCSDS HISTORICAL DOCUMENT November 1992 CCSDS HISTORICAL DOCUMENT CCSDS RECOMMENDATION FOR TELECOMMAND: DATA ROUTING SERVICE (2) OUTPUTS To the Packetization layer or other layer above: (a) Reconstructed User Data Units. To the sending end of the Segmentation layer: None. To the Transfer layer below: (b) Information concerning the ability of the Segmentation layer to accept more data. (3) INTERNAL FUNCTIONS (a) Receives TC Frame Data Units from the Transfer layer, delivered on individual Virtual Channels. (b) Sorts TC Frame Data Units associated with individual VCs according to their MAP identifier and reassembles the Segments associated with a particular MAP to reconstruct the TC User Data Unit. (c) Determines when all TC Segments associated with a particular TC User Data Unit have been received correctly. (d) Extracts the TC Packets. (e) Passes the reconstructed TC User Data Units to the Packetization layer or other higher layer. B-3 TC TRANSFER LAYER SERVICE SPECIFICATION The service provided by the TC Transfer Frame layer is to encapsulate Data Units within a suitable data structure, the TC Transfer Frame, for transmission through the physical channel which interconnects the sending and receiving ends of the TC System...
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This document was uploaded on 03/06/2014.

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