Unformatted text preview: The length of any Transfer Frame transferred on a
Physical Channel must be the same, and is established by management.
3.3 PACKET SERVICE 3.3.1 OVERVIEW OF 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. CCSDS 132.0-B-1 Page 3-3 September 2003 CCSDS RECOMMENDATION FOR TM SPACE DATA LINK PROTOCOL 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.
3.3.2 PACKET SERVICE PARAMETERS
188.8.131.52 General The parameters used by the Packet Service primitives shall conform to the specifications
contained in subsections 184.108.40.206 through 220.127.116.11.
18.104.22.168 Packet The Packet parameter shall contain a Packet for transfer by the Packet Service.
NOTE – The Packet parameter is the service data unit transferred by the Packet Service.
For restrictions on the Packets transferred by the Packet Service, see 3.2.2.
22.214.171.124 GVCID The GVCID parameter shall contain a GVCID that indicates the Virtual Channel through
which the Packet is to be transferred.
NOTE – The GVCID parameter is part of the SAP address of the Packet Service.
126.96.36.199 Packet Version Number NOTE – The Packet Version Number parameter is part of the SAP address of the Packet
Service and identifies the protocol entity of the upper layer that uses the Packet
188.8.131.52 Packet Quality Indicat...
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- Spring '14
- Space Exploration, European Space Agency, Protocol data unit