dccp.txt 1.4 KB

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  1. DCCP protocol
  2. ============
  3. Last updated: 10 November 2005
  4. Contents
  5. ========
  6. - Introduction
  7. - Missing features
  8. - Socket options
  9. - Notes
  10. Introduction
  11. ============
  12. Datagram Congestion Control Protocol (DCCP) is an unreliable, connection
  13. based protocol designed to solve issues present in UDP and TCP particularly
  14. for real time and multimedia traffic.
  15. It has a base protocol and pluggable congestion control IDs (CCIDs).
  16. It is at draft RFC status and the homepage for DCCP as a protocol is at:
  17. http://www.icir.org/kohler/dcp/
  18. Missing features
  19. ================
  20. The DCCP implementation does not currently have all the features that are in
  21. the draft RFC.
  22. In particular the following are missing:
  23. - CCID2 support
  24. - feature negotiation
  25. When testing against other implementations it appears that elapsed time
  26. options are not coded compliant to the specification.
  27. Socket options
  28. ==============
  29. DCCP_SOCKOPT_PACKET_SIZE is used for CCID3 to set default packet size for
  30. calculations.
  31. DCCP_SOCKOPT_SERVICE sets the service. This is compulsory as per the
  32. specification. If you don't set it you will get EPROTO.
  33. Notes
  34. =====
  35. SELinux does not yet have support for DCCP. You will need to turn it off or
  36. else you will get EACCES.
  37. DCCP does not travel through NAT successfully at present. This is because
  38. the checksum covers the psuedo-header as per TCP and UDP. It should be
  39. relatively trivial to add Linux NAT support for DCCP.