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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.