From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f43.google.com (mail-yw0-f43.google.com [209.85.213.43]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id CE4EA200844 for ; Sat, 10 Sep 2011 10:59:28 -0700 (PDT) Received: by ywm21 with SMTP id 21so1364517ywm.16 for ; Sat, 10 Sep 2011 10:59:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; bh=U/6cvR8CRroqAbTdRBKIOIR1VTIRcesrODDvQY8dfOo=; b=e4vQ3k/sEIdxWLd04HCqUV1Os41YCeTXJkjCUPJRnliTufJB1E5+lNW9VIRKte16jm YGVIxcSnl5qL/CuvEQvlslXzgqoeA9OCtu9tfJZlcIi8ForKCe9ydbxO/1unXcqEwNgy DIRo3ocDMJyJ7ROYN8rF66n9/7LXBLrQaWPto= MIME-Version: 1.0 Received: by 10.42.151.196 with SMTP id f4mr1154442icw.314.1315677566969; Sat, 10 Sep 2011 10:59:26 -0700 (PDT) Received: by 10.43.133.129 with HTTP; Sat, 10 Sep 2011 10:59:26 -0700 (PDT) Date: Sat, 10 Sep 2011 10:59:26 -0700 Message-ID: From: Dave Taht To: bloat Content-Type: multipart/alternative; boundary=90e6ba6e837804a87504ac9a0e67 Subject: [Bloat] mooseshaper? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Sep 2011 17:59:29 -0000 --90e6ba6e837804a87504ac9a0e67 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable ---------- Forwarded message ---------- From: Jim Gettys Date: Sat, Sep 10, 2011 at 10:45 AM Subject: Fwd: caidathoughts on bufferbloat To: Dave Taht Note the moosehaper. Worth reading through in general. on caida chat room so far: kenyon says, "hooray bufferbloat believers. I've been on the bufferbloat.ne= t mailing list for a while. I do traffic shaping on my router to work aro= und bufferbloat. Otherwise latency is horrible during large transfers." You [to kenyon]: told him he really needs a blog entry showing how people c= an traffic shape their own home routers to prove to themselves it's real, i.e., that manipulating parameters to avoid buffer bloat makes a diff Josh wants to be a believer You [to Josh]: http://arstechnica.com/tech-policy/news/2011/01/understanding-bufferblo= at-a nd-the-network-buffer-arms-race.ars kenyon [to you]: yes, but I guess it's hard or impossible unless you're running a "real" operating system on your router. amogh says, "so the "solution" is to shape your upstream bandwidth to less than the upstream capacity (which is already much less than your downstream capacity)?" You [to kenyon]: i thought most of these things use openwrt in the meantime kenyon [to amogh]: yes, I think so. You [to kenyon]: tho i guess cisco linksys are running a very old linux ker= nel kenyon [to amogh]: also, same for the downstream, since the latency problem= is the same for large downloads, at least for me. kenyon says, "OpenWrt is the way to go if you have a compatible device." kenyon uses mooseshaper | http://bazaar.launchpad.net/~malcscott/mooseshaper/trunk/view/head:/moo= sesh aper amogh [to kenyon]: do you see more packet loss when you do this shaping? kenyon [to amogh]: it does cause packet loss, but I don't really "see" it. Can't see it with e.g. ping, since it is prioritized. Here is my curren= t tc output, which does show that packets get dropped: http://paste.pocoo.org/show/473276/ kenyon says, "I wouldn't say downloads take a lot longer. I set my downstre= am to 10000 kb/s, which is only a few Mb/s less than I could get with this connection." amogh [to kenyon]: hmmm, I guess I need to learn more about how this shapin= g works and in particular how it affects loss rate Josh says, "Looks like my Cisco/Linksys E3000 will not run OpenWrt but woul= d run DD-WRT or Tomato" Josh has extremely mixed household of web browsing, gaming, netflixing, and SSH sessions dan has a household of one that mixes web browsing, gaming, netflixing, and ssh sessions. ;) kenyon says, "also, ECN=3D1 http://en.wikipedia.org/wiki/Explicit_Congestion_Notification#Linux :)" amogh says, "ISPs (or router vendors) should ideally allow users to specify their typical traffic mix (long-running, short/interactive, mixed) and provide buffer size settings for each traffic mix. But this seems highl= y unlikely to happen, because as soon as you set short buffers but run a long upload/download, you'll have non-negligible packet loss rate, and ISPs don't want any of that.." kenyon [to amogh]: that's why you need to prioritize traffic so that the packet loss happens on the long transfer, where you don't notice it - T= CP just does its flow/congestion control stuff. If the long transfer is UD= P, then I don't know, I guess the application will do its own buffering. amogh [to kenyon]: you don't notice it probably because we're more tolerant= of delays in long transfers. but TCP throughput is inversely proportional = to sq-root of loss rate, so if your loss rate changes from 1% to 2% (say), your TCP throughput goes down by a factor of 1.4 so shortening the buffers makes interactive traffic snappy, but makes your file transfers take longer. i think you need to quantify this tradeoff for a range of home traffic mixes.... have you talked to renata about her homenet profiler tool?http://cmon.lip6.fr/hnp/pages/home k --=20 Dave T=E4ht SKYPE: davetaht US Tel: 1-239-829-5608 http://the-edge.blogspot.com --90e6ba6e837804a87504ac9a0e67 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

---------- Forwarded message ----------<= br>From: Jim Gettys <= ;jg@freedesktop.org>Date: Sat, Sep 10, 2011 at 10:45 AM
Subject: Fwd: caidathoughts on bufferbloat
To: Dave Taht <dave.taht@gmail.com>


=20 =20 =20

Note the moosehaper.=A0 Worth reading through in general.


=A0 
on caida chat room so far:


kenyon says, "hooray bufferbloat believers. I've been on the bufferbloat.net
    mailing list for a while. I do traffic shaping on my router to work aro=
und
    bufferbloat. Otherwise latency is horrible during large transfers."=
;
You [to kenyon]: told him he really needs a blog entry showing how people c=
an
    traffic shape their own home routers to prove to themselves it's re=
al,
    i.e., that manipulating parameters to avoid buffer bloat makes a diff
Josh wants to be a believer
You [to Josh]:
    http://arstechnica.com/tech-policy/news/=
2011/01/understanding-bufferbloat-a
    nd-the-network-buffer-arms-race.ars
kenyon [to you]: yes, but I guess it's hard or impossible unless you=
9;re
    running a "real" operating system on your router.
amogh says, "so the "solution" is to shape your upstream ban=
dwidth to less
    than the upstream capacity (which is already much less than your
    downstream capacity)?"
You [to kenyon]: i thought most of these things use openwrt in the meantime
kenyon [to amogh]: yes, I think so.
You [to kenyon]: tho i guess cisco linksys are running a very old linux ker=
nel
kenyon [to amogh]: also, same for the downstream, since the latency problem=
 is
    the same for large downloads, at least for me.
kenyon says, "OpenWrt is the way to go if you have a compatible device=
."
kenyon uses mooseshaper |
    http://bazaar.launchpad.net/~malcscott=
/mooseshaper/trunk/view/head:/moosesh
    aper
amogh [to kenyon]: do you see more packet loss when you do this shaping?
kenyon [to amogh]: it does cause packet loss, but I don't really "=
see" it.
    Can't see it with e.g. ping, since it is prioritized. Here is my cu=
rrent
    tc output, which does show that packets get dropped:
    http:=
//paste.pocoo.org/show/473276/
kenyon says, "I wouldn't say downloads take a lot longer. I set my=
 downstream
    to 10000 kb/s, which is only a few Mb/s less than I could get with this
    connection."
amogh [to kenyon]: hmmm, I guess I need to learn more about how this shapin=
g
    works and in particular how it affects loss rate
Josh says, "Looks like my Cisco/Linksys E3000 will not run OpenWrt but=
 would
    run DD-WRT or Tomato"
Josh has extremely mixed household of web browsing, gaming, netflixing, and
    SSH sessions
dan has a household of one that mixes web browsing, gaming, netflixing, and
    ssh sessions.  ;)
kenyon says, "also, ECN=3D1
    http://en.wikipedia.org/wiki/Explicit_Congestion=
_Notification#Linux :)"
amogh says, "ISPs (or router vendors) should ideally allow users to sp=
ecify
    their typical traffic mix (long-running, short/interactive, mixed) and
    provide buffer size settings for each traffic mix. But this seems highl=
y
    unlikely to happen, because as soon as you set short buffers but run a
    long upload/download, you'll have non-negligible packet loss rate, =
and
    ISPs don't want any of that.."
kenyon [to amogh]: that's why you need to prioritize traffic so that th=
e
    packet loss happens on the long transfer, where you don't notice it=
 - TCP
    just does its flow/congestion control stuff. If the long transfer is UD=
P,
    then I don't know, I guess the application will do its own bufferin=
g.
amogh [to kenyon]: you don't notice it probably because we're more =
tolerant of
    delays in long transfers. but TCP throughput is inversely proportional =
to
    sq-root of loss rate, so if your loss rate changes from 1% to 2% (say),
    your TCP throughput goes down by a factor of 1.4

so shortening the buffers makes interactive traffic snappy, but=20
makes your file transfers take longer.  i think you need to=20
quantify this tradeoff for a range of home traffic mixes.... =20
have you talked to renata about her homenet profiler tool?
http://cmo=
n.lip6.fr/hnp/pages/home

k



--
Dave T=E4ht
SKYPE: davetaht
US= Tel: 1-239-829-5608
http://the-edge.blogspot.com
--90e6ba6e837804a87504ac9a0e67--