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1DCCP protocol
2============
3
4Last updated: 10 November 2005
5
6Contents
7========
8
9- Introduction
10- Missing features
11- Socket options
12- Notes
13
14Introduction
15============
16
17Datagram Congestion Control Protocol (DCCP) is an unreliable, connection
18based protocol designed to solve issues present in UDP and TCP particularly
19for real time and multimedia traffic.
20
21It has a base protocol and pluggable congestion control IDs (CCIDs).
22
23It is at draft RFC status and the homepage for DCCP as a protocol is at:
24 http://www.icir.org/kohler/dcp/
25
26Missing features
27================
28
29The DCCP implementation does not currently have all the features that are in
30the draft RFC.
31
32In particular the following are missing:
33- CCID2 support
34- feature negotiation
35
36When testing against other implementations it appears that elapsed time
37options are not coded compliant to the specification.
38
39Socket options
40==============
41
42DCCP_SOCKOPT_PACKET_SIZE is used for CCID3 to set default packet size for
43calculations.
44
45DCCP_SOCKOPT_SERVICE sets the service. This is compulsory as per the
46specification. If you don't set it you will get EPROTO.
47
48Notes
49=====
50
51SELinux does not yet have support for DCCP. You will need to turn it off or
52else you will get EACCES.
53
54DCCP does not travel through NAT successfully at present. This is because
55the checksum covers the psuedo-header as per TCP and UDP. It should be
56relatively trivial to add Linux NAT support for DCCP.