Overview
The data link layer imposes structure on the data passing between the network layer above and the coding layer below: frame boundaries, addressing, multiplexing, security, and optional per-hop reliability. It operates on individual point-to-point links — each ISL and each ground link has its own independent data link layer instance.
- cFE Headers — mission-specific secondary headers for TM and TC
- Packet Protocol — CCSDS Space Packet Protocol (SPP)
- Transfer Frame — frame protocols for point-to-point links
- Security — Space Data Link Security (SDLS)
- Reliability — COP-1 per-hop reliable delivery