Date: Sat, 17 Nov 2001 18:08:03 -0600 From: Alfred Perlstein <bright@mu.org> To: murthy kn <knmurthy30@hotmail.com> Cc: net@FreeBSD.ORG Subject: Re: TCP Fast Retransmit Message-ID: <20011117180803.D13393@elvis.mu.org> In-Reply-To: <F178MZMtjQ4S8Uq5nlh0000f0a7@hotmail.com>; from knmurthy30@hotmail.com on Sat, Nov 17, 2001 at 10:24:28PM %2B0530 References: <F178MZMtjQ4S8Uq5nlh0000f0a7@hotmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
* murthy kn <knmurthy30@hotmail.com> [011117 10:54] wrote:
> Hello,
>
> 1. Is there any sysctl variable to control the number of
> duplicate acks after which the sending TCP gets into a fast
> retransmit mode?
No, but you can add one like so (i think):
Index: tcp_input.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/tcp_input.c,v
retrieving revision 1.141
diff -u -r1.141 tcp_input.c
--- tcp_input.c 12 Sep 2001 08:37:54 -0000 1.141
+++ tcp_input.c 18 Nov 2001 00:09:51 -0000
@@ -101,6 +101,9 @@
MALLOC_DEFINE(M_TSEGQ, "tseg_qent", "TCP segment queue entry");
static int tcprexmtthresh = 3;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, rexmtthresh, CTLFLAG_RW,
+ &tcprexmtthresh, 0, "Max duplicate acks before fast rexmit");
+
tcp_cc tcp_ccgen;
struct tcpstat tcpstat;
> 2. If I have a switch that does not support any port aggregation,
> and it is connected to a BSD machine with 2 ethernet NICs that have
> identical MAC, will the switch forward *each* packet destined to the BSD
> machine to both of the NICs.
>
> 3. Apart from using tcpdump, are there any other tools/ways to analyze the
> dynamic behaviour of a BSD stack - like knowing when there have
> been retransmits, the state of various buffers in the stack etc.
netstat.
--
-Alfred Perlstein [alfred@freebsd.org]
'Instead of asking why a piece of software is using "1970s technology,"
start asking why software is ignoring 30 years of accumulated wisdom.'
http://www.morons.org/rants/gpl-harmful.php3
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20011117180803.D13393>