From: "Richard Scheffenegger" <rscheff@gmx.at>
To: <BeckW@telekom.de>, <sgunderson@bigfoot.com>,
<bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] Not all the world's a WAN
Date: Tue, 23 Aug 2011 09:37:32 +0200 [thread overview]
Message-ID: <BCA035584D37472A9CB3E6E9C6525456@srichardlxp2> (raw)
In-Reply-To: <AAE428925197FE46A5F94ED6643478FEA91BE93823@HE111644.EMEA1.CDS.T-INTERNAL.COM>
Some do. i.e. l3 capable switches, broadcom scorpio (and later) can do ecn
marking based on l2 buffer occupancy.
see the paper from stanford/microsoft about dctcp - ecn marking based on
instantaneous buffer occupancy and proportional tcp reaction (rather than
halving cwnd) per rtt...
rgds
----- Original Message -----
From: <BeckW@telekom.de>
To: <sgunderson@bigfoot.com>; <bloat@lists.bufferbloat.net>
Sent: Friday, August 19, 2011 4:59 PM
Subject: Re: [Bloat] Not all the world's a WAN
>> [...]so over short intervals the switch's aggregate incoming bandwidth
>> (multiple 10GbE links from
>> servers) is larger than its outgoing bandwidth (single 10GbE link to
>> client).
>
> Well, this kind of burstiness is the reason why we have buffers at all.
>
> Restricting the window size limits the TCP speed and keeps it this way
> from overflowing the buffer outside of bursty periods.
>
> ECN marking helps TCP to distinguish between really available bandwidth
> and 'fake' bandwidth that just fills up a buffer, at least if the feedback
> loop is fast enough. Do ethernet switches support ECN marking?
>
> _______________________________________________
> Bloat mailing list
> Bloat@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/bloat
next prev parent reply other threads:[~2011-08-23 6:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-18 1:26 Patrick J. LoPresti
2011-08-18 3:57 ` Stephen Hemminger
2011-08-18 7:45 ` Neil Davies
2011-08-18 5:08 ` Steinar H. Gunderson
2011-08-19 14:59 ` BeckW
2011-08-23 7:37 ` Richard Scheffenegger [this message]
2011-08-23 7:44 ` Richard Scheffenegger
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
List information: https://lists.bufferbloat.net/postorius/lists/bloat.lists.bufferbloat.net/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BCA035584D37472A9CB3E6E9C6525456@srichardlxp2 \
--to=rscheff@gmx.at \
--cc=BeckW@telekom.de \
--cc=bloat@lists.bufferbloat.net \
--cc=sgunderson@bigfoot.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