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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2010-08-29 19:23:14 +0000
committerDavid S. Miller <davem@davemloft.net>2010-08-30 13:45:28 -0700
commit89858ad14307a398961a0f1414b04053c1475e4f (patch)
tree860eca4c0fb4c9c470d407407ba051ae814c9dfa /Documentation/networking
parent4886fcad6e12572afbd230dfab1b268eace20d6d (diff)
dccp ccid-3: use per-route RTO or TCP RTO as fallback
This makes RTAX_RTO_MIN also available to CCID-3, replacing the compile-time RTO lower bound with a per-route tunable value. The original Kconfig option solved the problem that a very low RTT (in the order of HZ) can trigger too frequent and unnecessary reductions of the sending rate. This tunable does not affect the initial RTO value of 2 seconds specified in RFC 5348, section 4.2 and Appendix B. But like the hardcoded Kconfig value, it allows to adapt to network conditions. The same effect as the original Kconfig option of 100ms is now achieved by > ip route replace to unicast 192.168.0.0/24 rto_min 100j dev eth0 (assuming HZ=1000). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/dccp.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index cdb64922ba1..271d524a4c8 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -174,6 +174,9 @@ Per-route rto_min support
> ip route change 10.0.0.0/24 rto_min 250j dev wlan0
> ip route add 10.0.0.254/32 rto_min 800j dev wlan0
> ip route show dev wlan0
+ CCID-3 also supports the rto_min setting: it is used to define the lower
+ bound for the expiry of the nofeedback timer. This can be useful on LANs
+ with very low RTTs (e.g., loopback, Gbit ethernet).
Notes