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menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
depends on EXPERIMENTAL
config IP_DCCP_CCID2_DEBUG
bool "CCID-2 debugging messages"
---help---
Enable CCID-2 specific debugging messages.
The debugging output can additionally be toggled by setting the
ccid2_debug parameter to 0 or 1.
If in doubt, say N.
config IP_DCCP_CCID3
bool "CCID-3 (TCP-Friendly) (EXPERIMENTAL)"
def_bool y if (IP_DCCP = y || IP_DCCP = m)
select IP_DCCP_TFRC_LIB
---help---
CCID-3 denotes TCP-Friendly Rate Control (TFRC), an equation-based
rate-controlled congestion control mechanism. TFRC is designed to
be reasonably fair when competing for bandwidth with TCP-like flows,
where a flow is "reasonably fair" if its sending rate is generally
within a factor of two of the sending rate of a TCP flow under the
same conditions. However, TFRC has a much lower variation of
throughput over time compared with TCP, which makes CCID-3 more
suitable than CCID-2 for applications such streaming media where a
relatively smooth sending rate is of importance.
CCID-3 is further described in RFC 4342,
http://www.ietf.org/rfc/rfc4342.txt
The TFRC congestion control algorithms were initially described in
RFC 5448.
This text was extracted from RFC 4340 (sec. 10.2),
http://www.ietf.org/rfc/rfc4340.txt
If in doubt, say N.
config IP_DCCP_CCID3_DEBUG
bool "CCID-3 debugging messages"
depends on IP_DCCP_CCID3
---help---
Enable CCID-3 specific debugging messages.
The debugging output can additionally be toggled by setting the
ccid3_debug parameter to 0 or 1.
If in doubt, say N.
config IP_DCCP_CCID3_RTO
int "Use higher bound for nofeedback timer"
default 100
depends on IP_DCCP_CCID3 && EXPERIMENTAL
---help---
Use higher lower bound for nofeedback timer expiration.
The TFRC nofeedback timer normally expires after the maximum of 4
RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
with a small RTT this can mean a high processing load and reduced
performance, since then the nofeedback timer is triggered very
frequently.
This option enables to set a higher lower bound for the nofeedback
value. Values in units of milliseconds can be set here.
A value of 0 disables this feature by enforcing the value specified
in RFC 3448. The following values have been suggested as bounds for
experimental use:
* 16-20ms to match the typical multimedia inter-frame interval
* 100ms as a reasonable compromise [default]
* 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
The default of 100ms is a compromise between a large value for
efficient DCCP implementations, and a small value to avoid disrupting
the network in times of congestion.
The purpose of the nofeedback timer is to slow DCCP down when there
is serious network congestion: experimenting with larger values should
therefore not be performed on WANs.
config IP_DCCP_TFRC_LIB
tristate
default n
config IP_DCCP_TFRC_DEBUG
bool
depends on IP_DCCP_TFRC_LIB
default y if IP_DCCP_CCID3_DEBUG
endmenu
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