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Unformatted text preview: r, Master Channel Operational
Control Field, and Master Channel Frame) are provided for a Master Channel. Table 2-1
summarizes these services. CCSDS 132.0-B-1 Page 2-6 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL Table 2-1: Summary of Services Provided by TM Space Data Link Protocol
Service Service Type Service Data
Unit SAP Address Packet Asynchronous Packet GVCID + Packet
Version Number Virtual Channel Access (VCA) Asynchronous or
Periodic VCA_SDU GVCID Virtual Channel Frame
Secondary Header (VC_FSH) Synchronous or
Periodic FSH_SDU GVCID Virtual Channel Operational
Control Field (VC_OCF) Synchronous or
Periodic OCF_SDU GVCID Virtual Channel Frame (VCF) Asynchronous or
Periodic Transfer Frame GVCID Master Channel Frame
Secondary Header (MC_FSH) Synchronous or
Periodic FSH_SDU MCID Master Channel Operational
Control Field (MC_OCF) Synchronous or
Periodic OCF_SDU MCID Master Channel Frame (MCF) Asynchronous or
Periodic Transfer Frame MCID 220.127.116.11 Packet Service The Packet Service transfers a sequence of variable-length, delimited, octet-aligned service
data units known as Packets across a space link. The Packets transferred by this service must
have a Packet Version Number (PVN) authorized by CCSDS. For the Packet Version
Numbers presently authorized by CCSDS, see reference . The service is unidirectional,
asynchronous and sequence-preserving. It does not guarantee completeness, nor does it
signal gaps in the sequence of service data units delivered to a receiving user.
A user of this service is a protocol entity that sends or receives Packets with a single PVN. A
user is identified with the PVN and a GVCID. Different users (i.e., Packets with different
versions) can share a single Virtual Channel, and if there are multiple users on a Virtual
Channel, the service provider multiplexes Packets of different versions to form a single
stream of Packets to be transferred on that Virtual Channel. CCSDS 132.0-B-1 Page 2-7 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL 18.104.22.168 Virtual Channel Access (VCA) Service The Virtual Channel Access (VCA) Service provides transfer of a sequence of privately
formatted service data units of fixed...
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This document was uploaded on 03/06/2014.
- Spring '14