[TCP] FRTO: Sysctl documentation for SACK enhanced version

The description is overly verbose to avoid ambiguity between
"SACK enabled" and "SACK enhanced FRTO"

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 702d1d8dd04a..719b42907314 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -183,7 +183,10 @@ tcp_frto - BOOLEAN
         Enables F-RTO, 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.
+        rather than intermediate router congestion. If set to 1, basic
+        version is enabled. 2 enables SACK enhanced FRTO, which is
+        EXPERIMENTAL. The basic version can be used also when SACK is
+        enabled for a flow through tcp_sack sysctl.
 
 tcp_keepalive_time - INTEGER
         How often TCP sends out keepalive messages when keepalive is enabled.