From: Andi Kleen <ak@suse.de>
To: "Stuart MacDonald" <stuartm@connecttech.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: TCP stack behaviour question
Date: 20 Sep 2006 11:54:44 +0200 [thread overview]
Message-ID: <p73eju6kgm3.fsf@verdi.suse.de> (raw)
In-Reply-To: <006301c6dbf4$035a71c0$294b82ce@stuartm>
"Stuart MacDonald" <stuartm@connecttech.com> writes:
>
>
> *** I found arp(7) and read up on it while I was typing. And now I see
> something interesting in the tcpdump; my app is actually talking on
> two TCP connections at the same time. Both are in retransmit phase,
> and the first arp is 5 seconds (delay_first_probe_time) after an
> _aggregate total_ of 15 retransmits (being the two original unanswered
> packets and 7 and 6 retransmits of each).
>
> My reading of tcp(7)'s documentation of tcp_retries2 is that
> tcp_retries2 is a per-TCP packet count. My tcpdump seems to show that
> it is in fact a global count. Which is correct?
The ARP layer keeps track of what neighbours are reachable and doesn't
transmit packets to unreachable ones before they answer unicast or
broadcast ARP. This is a state machine borrowed from IPv6.
There is nothing global.
-Andi
next prev parent reply other threads:[~2006-09-20 9:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-18 18:29 TCP stack behaviour question Stuart MacDonald
2006-09-19 12:03 ` Samuel Tardieu
2006-09-19 14:00 ` Stuart MacDonald
2006-09-20 9:54 ` Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-09-15 17:28 Stuart MacDonald
2006-09-18 8:29 ` Andi Kleen
2006-09-18 13:20 ` Stuart MacDonald
2006-09-18 13:54 ` Andi Kleen
2006-09-18 14:19 ` Stuart MacDonald
2006-09-18 14:31 ` Andi Kleen
2006-09-18 15:38 ` Michael Kerrisk
2006-09-18 17:01 ` Stuart MacDonald
2006-09-19 6:13 ` Michael Kerrisk
2006-09-19 6:47 ` Andi Kleen
2006-09-19 14:50 ` Michael Kerrisk
2006-09-20 9:55 ` Andi Kleen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=p73eju6kgm3.fsf@verdi.suse.de \
--to=ak@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=stuartm@connecttech.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox