From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qw0-f43.google.com (mail-qw0-f43.google.com [209.85.216.43]) (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 D90BB201A79 for ; Mon, 16 May 2011 08:14:36 -0700 (PDT) Received: by qwf6 with SMTP id 6so3540317qwf.16 for ; Mon, 16 May 2011 08:23:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:sender:message-id:date:from:organization :user-agent:mime-version:to:subject:references:in-reply-to :content-type:content-transfer-encoding; bh=f3Vb3AsjRhWKWEZ0LXvwW6fwh5XjPqsEDYdWnsn2hLM=; b=s/cQ6aRCWF94hzkPlh+9489+oyFRoRaQjBu9H1VGz2rvAFbnsFkqNITmdPdL9HHCzN tuDxFwbn8FqYGy7dobslPI4H8hmBdtONd/RZhWV3lyfQGbY3PbTIZmT03aiVctciNIZt iD1MjveivnFUdaowaUn4WARyvly//UZwe0gjQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:organization:user-agent:mime-version:to :subject:references:in-reply-to:content-type :content-transfer-encoding; b=i/8rOzlqOMLie7QGcDBYaNTE/nYlthiF6HOqFIn1wRJR9gbpaT97tsswueuHuA3+p8 0Z45eJqWodw66bi1SE3EhkHeM9mfE2kVDlJV/h32nmEt7uA47GO9eFpXdnyEA7HPIOKD 4Vk8s+NqMAAfUvGYvTnftZ52U5ziZzTDu3Ct4= Received: by 10.224.187.70 with SMTP id cv6mr3219447qab.347.1305559410856; Mon, 16 May 2011 08:23:30 -0700 (PDT) Received: from [192.168.1.119] (c-98-229-99-32.hsd1.ma.comcast.net [98.229.99.32]) by mx.google.com with ESMTPS id c27sm3252998qck.22.2011.05.16.08.23.28 (version=SSLv3 cipher=OTHER); Mon, 16 May 2011 08:23:29 -0700 (PDT) Sender: Jim Gettys Message-ID: <4DD1416F.9080302@freedesktop.org> Date: Mon, 16 May 2011 11:23:27 -0400 From: Jim Gettys Organization: Bell Labs User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110424 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: bloat@lists.bufferbloat.net References: <4DC2C9D2.8040703@freedesktop.org> <20110505091046.3c73e067@nehalam> <6E25D2CF-D0F0-4C41-BABC-4AB0C00862A6@pnsol.com> <35D8AC71C7BF46E29CC3118AACD97FA6@srichardlxp2> <1304964368.8149.202.camel@tardy> <4DD9A464-8845-49AA-ADC4-A0D36D91AAEC@cisco.com> <1305297321.8149.549.camel@tardy><014c01cc11a8$de78ac10$9b6a0430$@gross@avanw.com><8A928839-1D91-4F18-8252-F06BD004E37D@cisco.com><5946BA6B-4E00-43AF-A8A2-17FB3769F37B@cisco.com> <2EEFB9D5-E9CC-4612-8D91-F6B382E3C2FB@gmail.com> <13672E5D-7EAE-446A-A8D8-BA85EF2CE72E@cisco.com> <4DD10938.7020703@freedesktop.o rg> <012d01cc13cb$61617ed0$24247c70$@gross@avanw.com> <4DD12520.8050604@freedesktop.org> <013401cc13cf$098ee720$1cacb560$@gross@avanw.com> In-Reply-To: <013401cc13cf$098ee720$1cacb560$@gross@avanw.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] Jumbo frames and LAN buffers 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: Mon, 16 May 2011 15:14:37 -0000 On 05/16/2011 09:42 AM, Kevin Gross wrote: > I would like to try this. Can you suggest specific equipment to look at. Due > to integration and low port count, most of the cheap consumer stuff has > surprisingly good layer-2 performance. I've tested a bunch of Linksys and > other small/medium business 5 to 24 port gigabit switches. Since I measure > latency, I expect I would have noticed if flow control were kicking in. I think I was using a D-Link DGS2208. (8 port consumer switch). I then went and looked at the spec sheets of some of the other consumer kit out there and found they all had the "feature" of 802.3 flow control. I may have been using iperf to tickle it, rather than ssh. I was also playing around with an old 100Mbps switch, as documented in my blog; I don't remember if I saw it there. - Jim > Kevin Gross > > -----Original Message----- > From: bloat-bounces@lists.bufferbloat.net > [mailto:bloat-bounces@lists.bufferbloat.net] On Behalf Of Jim Gettys > Sent: Monday, May 16, 2011 7:23 AM > To: bloat@lists.bufferbloat.net > Subject: Re: [Bloat] Jumbo frames and LAN buffers > > On 05/16/2011 09:15 AM, Kevin Gross wrote: >> All the stand-alone switches I've looked at recently either do not support >> 802.3x or support it in the (desireable) manner described in the last >> paragraph of the linked blog post. I don't believe Ethernet flow control > is >> a factor in current LANs. I'd be interested to know the specifics if > anyone >> sees it differently. > Heh. Plug wireshark into current off the shelf cheap consumer switches > intended for the home. You won't like what you see. And you have no > way to manage them. I was quite surprised last fall when doing my home > experiments to see 802.3 frames; I had been blissfully unaware of its > existence, and had to go read up on it as a result. > > I don't think any of the enterprise switches are so brain damaged. So i > suspect it's mostly lurking to cause trouble in home and small office > environments, exactly where no-one will know what's going on. > - Jim > > > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat