From: Ilpo Järvinen Date: Thu, 20 Sep 2007 18:35:26 +0000 (-0700) Subject: [TCP] FRTO: Update sysctl documentation X-Git-Tag: v2.6.24-rc1~1454^2~404 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cd99889c616afe1e8addcf28da505600c04f065a;p=linux-2.6 [TCP] FRTO: Update sysctl documentation Since the SACK enhanced FRTO was added, the code has been under test numerous times so remove "experimental" claim from the documentation. Also be a bit more verbose about the usage. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 32c2e9da5f..6ae2feff30 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -180,13 +180,20 @@ tcp_fin_timeout - INTEGER to live longer. Cf. tcp_max_orphans. tcp_frto - INTEGER - Enables F-RTO, an enhanced recovery algorithm for TCP retransmission + Enables Forward RTO-Recovery (F-RTO) defined in RFC4138. + 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. If set to 1, basic - 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. + rather than intermediate router congestion. FRTO is sender-side + only modification. Therefore it does not require any support from + the peer, but in a typical case, however, where wireless link is + the local access link and most of the data flows downlink, the + faraway servers should have FRTO enabled to take advantage of it. + 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 FRTO + 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