From: Andy Furniss <andy.furniss@dsl.pipex.com>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] Traffic shaping and MTU/MSS
Date: Wed, 26 Nov 2003 11:56:32 +0000 [thread overview]
Message-ID: <marc-lartc-106984964902830@msgid-missing> (raw)
In-Reply-To: <marc-lartc-106966386410469@msgid-missing>
On Monday 24 November 2003 7:35 am, Defekt wrote:
> Hi,
>
> I'm using traffic shaping on my home 1.5M/256K ADSL connection. The
> problem I'm running into is even when I'm shaping upload traffic (web
> server/p2p etc...) I run into latency issues with online gaming. This is
> of course due to the 256Kb upload and the 1492 MTU (PPPoE) which means a
> single large packet will take up to 40ms to transfer.
>
> What I would like to do is reduce the MSS for low priority traffic using
> ipchains based on a fwmark value. Is it possible to do this?
>
> Appreciate any other suggestions to solve this problem.
One thing to consider - assuming things are the same in your country as
mine, is that DSL modems are atm devices an send whole 53 byte cells. So
MTU = x+1 may send 53 bytes more than MTU = x, so choose carefully. I
can't tell you exactly how to see what is right for you as I use pppoa, I
think the overhead on pppoe is either 32 or 40 bytes, so you would find an
MTU (MSS+40) add say 32 then divide by 48 (as each 53 byte cell carries 48
data) and change MTU until you get a whole number.
If you can get your modem to give you a cell count you could test what the
correct pppoe overhead is with ping -s x you could change x until the cell
counter varied by 1 between x and x+1. If the overhead is 32 then ping -s
36 should send 2 cells (36 data + 8 ICMP + 20 IP +32 PPP = 96) & 37 three,
s = 28 for two cells / 29 for three if it's 40.
Andy.
Andy.
_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
prev parent reply other threads:[~2003-11-26 11:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-24 7:35 [LARTC] Traffic shaping and MTU/MSS Defekt
2003-11-24 23:48 ` Damion de Soto
2003-11-26 11:56 ` Andy Furniss [this message]
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=marc-lartc-106984964902830@msgid-missing \
--to=andy.furniss@dsl.pipex.com \
--cc=lartc@vger.kernel.org \
/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