2236 virtual channel frame vcf service the virtual

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Unformatted text preview: ot multiplexed together within one Virtual Channel. 2.2.3.6 Virtual Channel Frame (VCF) Service The Virtual Channel Frame (VCF) Service provides transfer of a sequence of fixed-length TM Transfer Frames of a Virtual Channel, created by an independent protocol entity, across a space link. The service is unidirectional, either asynchronous or periodic, and sequencepreserving. The service does not guarantee completeness, but it may signal gaps in the sequence of service data units delivered to the receiving user. CCSDS 132.0-B-1 Page 2-8 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL For a given service instance only one user, identified with the GVCID of the Virtual Channel, can use this service on a Virtual Channel. Service data units from different users are not multiplexed together within one Virtual Channel. The Virtual Channel Frame Service transfers the independently created TM Transfer Frames through a space link, together with TM Transfer Frames created by the service provider itself. This service is made available to trusted users who are certified during the design process to ensure that the independently created protocol data units do not violate the operational integrity of the space link. Necessarily, the independent Transfer Frames must have the same length as those generated by the service provider. 2.2.3.7 Master Channel Frame Secondary Header (MC_FSH) Service The Master Channel Frame Secondary Header (MC_FSH) Service provides synchronous transfer of fixed-length data units in the Transfer Frame Secondary Header (FSH) of Transfer Frames of a Master Channel. The service is unidirectional and sequence-preserving. The transfer is synchronized with the release of Transfer Frames of a Master Channel. The service does not guarantee completeness, but may signal gaps in the sequence of service data units delivered to a receiving user. Only one user can use this service on a Master Channel, and the user is identified with the MCID of the Master Channel. Service data units from different users are not multi...
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This document was uploaded on 03/06/2014.

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