kcppp

README

KCP++: KCP but better (NOT FINISHED!)

Why?

KCP is pretty well known, but:

• It's really poorly documented
• kcp-go's code quality is appalling
• It's a massive layering violation

KCP++ is a simplified, improved, and partially backwards-compatible reliable transport protocol on top of UDP or any other unreliable datagram transport. Some features include:

• Well-tuned bandwidth-probing congestion control based on BBR.
• Only handle reliable transport. ECC, encryption, etc belong on different layers.
• Better performance in really lossy environments through SACK.
• RST mechanism to terminate dead connections without timeout.

Packet header

• 4 bytes: conversation ID. Not really important except as a sanity check.
• 1 byte: command. One of
  • PUSH (81)
  • ACK (82)
  • WASK (83)
  • WINS (84)
  • SACK (91)
  • RST (0)
• 1 byte: Reserved, must be 0
• 2 bytes: receive window advertisement (in packets)
• 4 bytes: timestamp in ms
• 4 bytes: segment number
• 4 bytes: acknowledgement number