From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qy0-f178.google.com (mail-qy0-f178.google.com [209.85.216.178]) (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 A5DB6201A55 for ; Mon, 16 May 2011 06:13:05 -0700 (PDT) Received: by qyk2 with SMTP id 2so3059880qyk.16 for ; Mon, 16 May 2011 06:22:43 -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=VtRhZvQeABkuXRegWLmmOn/HTzFMcRAEZIVlK99TF34=; b=e/vB8WVTFXkmFkp09mjWwB158mmMXvAqnGM5p45lEi3D3S+PyOxG/gcT3Gvg/9UASi bpGFa6IFpaFYrpw4L+tsXL1epyaCac9vaNsN2AKnZSWj6buVJuVsQNwR+j/ivWRxE3In VkbTfIhzA5xt+Uy7iUCQTQI7LleO1Ae3m0sM4= 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=bCQGK6DhrbPJKgTBy9ngW4oj9HTP9NkyaKn0ABZlkakiLX/DfGz7NvAzZa4NsMf4UN gic4HkJzPkqWNVB0GatE+xPRJvwc1OCCiDiZHRx3qq1myrXUvTuLsLLpEnHErHFQencH HNw70Z6M0gmzexxAL6EnOg+MUTy9joKbCk5bY= Received: by 10.229.131.32 with SMTP id v32mr3274806qcs.35.1305552163282; Mon, 16 May 2011 06:22:43 -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 l10sm3198938qck.26.2011.05.16.06.22.41 (version=SSLv3 cipher=OTHER); Mon, 16 May 2011 06:22:42 -0700 (PDT) Sender: Jim Gettys Message-ID: <4DD12520.8050604@freedesktop.org> Date: Mon, 16 May 2011 09:22:40 -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: <4DB70FDA.6000507@mti-systems.com> <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> In-Reply-To: <012d01cc13cb$61617ed0$24247c70$@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 13:13:06 -0000 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 > My understanding is that 802.1au, "lossless Ethernet", was designed > primarily to allow Fibre Channel to be carried over 10 GbE so that SAN and > LAN can share a common infrastructure in datacenters. I don't believe anyone > intends for it to be enabled for traffic classes carrying TCP. > > 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 5:24 AM > To: bloat@lists.bufferbloat.net > Subject: Re: [Bloat] Jumbo frames and LAN buffers > > Not necessarily out of knowledge or desire (since it isn't usually > controllable in the small switches you buy for home). It can cause > trouble even in small environments as your house. > > http://virtualthreads.blogspot.com/2006/02/beware-ethernet-flow-control.html > > I know I'm at least three consumer switches deep, and it's not by choice. > - Jim > > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat