1 menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
2 depends on EXPERIMENTAL
4 config IP_DCCP_CCID2_DEBUG
5 bool "CCID-2 debugging messages"
7 Enable CCID-2 specific debugging messages.
9 The debugging output can additionally be toggled by setting the
10 ccid2_debug parameter to 0 or 1.
15 bool "CCID-3 (TCP-Friendly) (EXPERIMENTAL)"
16 def_bool y if (IP_DCCP = y || IP_DCCP = m)
17 select IP_DCCP_TFRC_LIB
19 CCID-3 denotes TCP-Friendly Rate Control (TFRC), an equation-based
20 rate-controlled congestion control mechanism. TFRC is designed to
21 be reasonably fair when competing for bandwidth with TCP-like flows,
22 where a flow is "reasonably fair" if its sending rate is generally
23 within a factor of two of the sending rate of a TCP flow under the
24 same conditions. However, TFRC has a much lower variation of
25 throughput over time compared with TCP, which makes CCID-3 more
26 suitable than CCID-2 for applications such streaming media where a
27 relatively smooth sending rate is of importance.
29 CCID-3 is further described in RFC 4342,
30 http://www.ietf.org/rfc/rfc4342.txt
32 The TFRC congestion control algorithms were initially described in
35 This text was extracted from RFC 4340 (sec. 10.2),
36 http://www.ietf.org/rfc/rfc4340.txt
40 config IP_DCCP_CCID3_DEBUG
41 bool "CCID-3 debugging messages"
42 depends on IP_DCCP_CCID3
44 Enable CCID-3 specific debugging messages.
46 The debugging output can additionally be toggled by setting the
47 ccid3_debug parameter to 0 or 1.
51 config IP_DCCP_CCID3_RTO
52 int "Use higher bound for nofeedback timer"
54 depends on IP_DCCP_CCID3 && EXPERIMENTAL
56 Use higher lower bound for nofeedback timer expiration.
58 The TFRC nofeedback timer normally expires after the maximum of 4
59 RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
60 with a small RTT this can mean a high processing load and reduced
61 performance, since then the nofeedback timer is triggered very
64 This option enables to set a higher lower bound for the nofeedback
65 value. Values in units of milliseconds can be set here.
67 A value of 0 disables this feature by enforcing the value specified
68 in RFC 3448. The following values have been suggested as bounds for
70 * 16-20ms to match the typical multimedia inter-frame interval
71 * 100ms as a reasonable compromise [default]
72 * 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
74 The default of 100ms is a compromise between a large value for
75 efficient DCCP implementations, and a small value to avoid disrupting
76 the network in times of congestion.
78 The purpose of the nofeedback timer is to slow DCCP down when there
79 is serious network congestion: experimenting with larger values should
80 therefore not be performed on WANs.
82 config IP_DCCP_TFRC_LIB
86 config IP_DCCP_TFRC_DEBUG
88 depends on IP_DCCP_TFRC_LIB
89 default y if IP_DCCP_CCID3_DEBUG