This preview shows page 1. Sign up to view the full content.
Unformatted text preview: rotocols provide services for transferring various types of SDUs on
space links, but the most important services are those for transferring variable-length data units
commonly known as Packets, that is, Protocol Data Units of protocols of the Network Layer,
such as the Space Packet Protocol (reference ), SCPS-NP (reference ), and IP
Each packet format transferred by the Space Data Link Protocols must have a Packet Version
Number (PVN) authorized by CCSDS. A list of the PVNs presently authorized by CCSDS is
contained in reference . A user of this service is a protocol entity that sends or receives
Packets with a single PVN. CCSDS 130.2-G-1 Page 3-7 December 2007 CCSDS REPORT CONCERNING THE SPACE DATA LINK PROTOCOLS 184.108.40.206 Services to Transfer Packets Provided by TC-SDLP The TC-SDLP has two services for transferring packets: the MAP (Multiplexer Access
Point) Packet Service (or the MAPP Service) and the Virtual Channel Packet Service (or the
VCP Service). These services transfer a sequence of Packets over a space link on a MAP
Channel (in the case of the MAPP Service) or a Virtual Channel (in the case of VCP
Both Sequence-Controlled (Type-A) and Expedited (Type-B) service types (see 220.127.116.11) are
provided for these services. The sending user specifies for each Packet whether Type-A or
Type-B should be applied.
Different users (i.e., Packets with different PVNs) can share a single MAP Channel (in the
case of the MAPP Service) or a single Virtual Channel (in the case of the VCP Service), and
if there are multiple users on a MAP or VC Channel, the service provider multiplexes
Packets with different PVNs to form a single stream of Packets to be transferred on that
18.104.22.168 Service to Transfer Packets Provided by TM-SDLP and AOS-SDLP The TM-SDLP and AOS-SDLP each have a service called the Packet Service for transferring
Packets. A sequence of Packets supplied by a sending user is transferred on a single Virtual
These services do not guarantee complete delivery of the Packets supplied by the sending
user to the receiving user, nor do they signal gaps in the sequence of Packets delivered to the
Different users (i.e., Packets with different PVNs) can share a single Virtual Channel, and if
there are multiple users on a Virtual Channel, the service provider multiplexes Packets with
different PVNs to form a single stream of Packets to be transferred on that Virtual Channel.
3.3.3 ENCAPSULATION SERVICE Packets with authorized PVNs can be directly transferred by the Space Data Link Protocols
using the services explained in 3.3.2. Packets that do not have an authorized PVN can be
transferred with a service called the Encapsulation Service, defined in reference . With this
service, Packets are transferred encapsulated in either Space Packets defined in reference 
or Encapsulation Packets defined in reference .
This service can be used with any Space Data Link Protocol and it uses a service provided...
View Full Document
This document was uploaded on 03/06/2014.
- Spring '14