From a93868fd3bb1d4b58c9ca20e3d24498d27bf6b42 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Fri, 21 Nov 2008 16:00:09 -0500 Subject: [PATCH] tcp.7: Update tcp_frto description for 2.6.22 changes Linux 2.6.22 added a mode value 2 ("Enable SACK-enhanced F-RTO if flow uses SACK"). Signed-off-by: Michael Kerrisk --- man7/tcp.7 | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/man7/tcp.7 b/man7/tcp.7 index e20d8ff38..b0f715c36 100644 --- a/man7/tcp.7 +++ b/man7/tcp.7 @@ -352,7 +352,7 @@ In Linux 2.2, the default value was 180. .\" .\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP -.IR tcp_frto " (Boolean; default: disabled; since Linux 2.4.21/2.6)" +.IR tcp_frto " (integer; default: 0; since Linux 2.4.21/2.6)" .\" Since 2.4.21/2.5.43 Enables F-RTO, an enhanced recovery algorithm for TCP retransmission timeouts (RTOs). @@ -360,6 +360,22 @@ It is particularly beneficial in wireless environments where packet loss is typically due to random radio interference rather than intermediate router congestion. See RFC 4138 for more details. + +This file can have one of the following values: +.RS +.IP 0 3 +Disabled. +.IP 1 +The basic version F-RTO algorithm is enabled. +.IP 2 +Enable SACK-enhanced F-RTO if flow uses SACK. +The basic version can be used also when +SACK is in use though in that case scenario(s) exists where F-RTO +interacts badly with the packet counting of the SACK-enabled TCP flow. +.RE +.IP +Before Linux 2.6.22, this parameter was a Boolean value, +supporting just values 0 and 1 above. .TP .IR tcp_frto_response " (integer; default: 0; since Linux 2.6.22)" When F-RTO has detected that a TCP retransmission timeout was spurious