From 89808060b7a71376cc2ba8092d43b2010da465b6 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Tue, 27 Feb 2007 10:10:55 -0800 Subject: [TCP] Sysctl documentation: tcp_frto_response MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In addition, fixed minor things in tcp_frto sysctl. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'Documentation/networking/ip-sysctl.txt') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 719b4290731..054c515bd72 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -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. -- cgit v1.2.3-70-g09d2