Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[firefly-linux-kernel-4.4.55.git] / Documentation / networking / ip-sysctl.txt

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 17953e2bc3e9f7bbedb10404a5fbdc4f8e326a04..f98ca633b5282eb838ae1b04f9497e4a4495f198 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -225,36 +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.
-
-tcp_frto_response - INTEGER
-       When F-RTO has detected that a TCP retransmission timeout was
-       spurious (i.e, the timeout would have been avoided had TCP set a
-       longer retransmission timeout), TCP has several options what to do
-       next. Possible values are:
-               0 Rate halving based; a smooth and conservative response,
-                 results in halved cwnd and ssthresh after one RTT
-               1 Very conservative response; not recommended because even
-                 though being valid, it interacts poorly with the rest of
-                 Linux TCP, halves cwnd and ssthresh immediately
-               2 Aggressive response; undoes congestion control measures
-                 that are now known to be unnecessary (ignoring the
-                 possibility of a lost retransmission that would require
-                 TCP to be more cautious), cwnd and ssthresh are restored
-                 to the values prior timeout
-       Default: 0 (rate halving based)
+       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.