[TCP] Sysctl documentation: tcp_frto_response

In addition, fixed minor things in tcp_frto sysctl.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2007-02-27 10:10:55 -08:00 committed by David S. Miller
parent 3cfe3baaf0
commit 89808060b7
1 changed files with 19 additions and 2 deletions

View File

@ -179,15 +179,32 @@ tcp_fin_timeout - INTEGER
because they eat maximum 1.5K of memory, but they tend
to live longer. Cf. tcp_max_orphans.
tcp_frto - BOOLEAN
tcp_frto - INTEGER
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. If set to 1, basic
version is enabled. 2 enables SACK enhanced FRTO, which is
version is enabled. 2 enables SACK enhanced F-RTO, which is
EXPERIMENTAL. The basic version can be used also when SACK is
enabled for a flow through tcp_sack sysctl.
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)
tcp_keepalive_time - INTEGER
How often TCP sends out keepalive messages when keepalive is enabled.
Default: 2hours.