About RTO retransmission and tcp_orphan_retries

About RTO retransmission and tcp_orphan_retries

tcp_orphan_retries - INTEGER
This value influences the timeout of a locally closed TCP connection,when RTO retransmissions remain
unacknowledged.

source :
Linux Kernel Documentation . 2.6.32

TYPICAL SHELL ON PROC FILESYSTEM
[bash]
$cat /proc/sys/net/ipv4/tcp_orphan_retries
0
$
[/bash]

TYPICAL SOURCE CODE RELATED
[c]
net/ipv4/tcp_timer.c – 39 identical
99: static int tcp_orphan_retries(struct sock *sk, int alive)
100: {
101: int retries = sysctl_tcp_orphan_retries; /* May be zero. */
157: retry_until = tcp_orphan_retries(sk, alive);
158:
android.git.kernel.org/kernel/msm.git – GPL – C – More from msm.git »
[/c]

[bash]
shaper.queues
176: echo "Set number of orphant retries to 5"
177: echo 5 > /proc/sys/net/ipv4/tcp_orphan_retries
178:
http://www.chronox.de/tc+filter/shaper-0.2.tar.bz2 – Unknown – Shell – More from shaper-0.2.tar.bz2 »
[/bash]
[text]
usr/share/man/man7/tcp.7
282: .TP
283: .B tcp_orphan_retries
284: The maximum number of attempts made to probe the other
www2.cddc.vt.edu/linux/distributions/7linux/7v6/7base/7v6a11.tar.bz2 – Unknown – Troff –
[/text]
TYPICAL EXPLANATION RELATED

The  tcp_orphan_retries variable  tells the  TCP/IP stack how many times to retry  to kill connections on
the other side before killing  it on our own side.  If your machine runs  as a  highly loaded  http
server it  may be  worth thinking  about lowering  this value.  http  sockets will consume large amounts of resources if not checked

This variable  takes an integer value.The default value for this variable is 7, which  would approximately correspond to 50 seconds  through 16 minutes depending on the Retransmission Timeout (RTO).


source :
Ipsysctl tutorial 1.0.4
Oskar Andreasson
blueflux@koffein.net
Copyright © 2002 by Oskar Andreasson