tcp: implement RFC5682 F-RTO

[karo-tx-linux.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 8a977a0aaede348316cac52b83822754adcc4bea..f98ca633b5282eb838ae1b04f9497e4a4495f198 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -225,19 +225,13 @@ tcp_fin_timeout - INTEGER
        Default: 60 seconds
 
 tcp_frto - INTEGER
-       Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.
+       Enables Forward RTO-Recovery (F-RTO) defined in RFC5682.
        F-RTO is an enhanced recovery algorithm for TCP retransmission
-       timeouts.  It is particularly beneficial in wireless environments
-       where packet loss is typically due to random radio interference
-       rather than intermediate router congestion.  F-RTO is sender-side
-       only modification. Therefore it does not require any support from
-       the peer.
-
-       If set to 1, basic version is enabled.  2 enables SACK enhanced
-       F-RTO if flow uses SACK.  The basic version can be used also when
-       SACK is in use though scenario(s) with it exists where F-RTO
-       interacts badly with the packet counting of the SACK enabled TCP
-       flow.
+       timeouts.  It is particularly beneficial in networks where the
+       RTT fluctuates (e.g., wireless). F-RTO is sender-side only
+       modification. It does not require any support from the peer.
+
+       By default it's enabled with a non-zero value. 0 disables F-RTO.
 
 tcp_keepalive_time - INTEGER
        How often TCP sends out keepalive messages when keepalive is enabled.