From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout-de.gmx.net (mailout-de.gmx.net [213.165.64.23]) by huchra.bufferbloat.net (Postfix) with SMTP id 60061201728 for ; Mon, 16 May 2011 11:07:19 -0700 (PDT) Received: (qmail invoked by alias); 16 May 2011 18:17:03 -0000 Received: from unknown (EHLO srichardlxp2) [213.143.107.142] by mail.gmx.net (mp057) with SMTP; 16 May 2011 20:17:03 +0200 X-Authenticated: #20720068 X-Provags-ID: V01U2FsdGVkX18l15g3yvMlx1w12J4gYP3zERdB1GozEWxC/OEXOP HECmSwSze2a5Js Message-ID: From: "Richard Scheffenegger" To: "Fred Baker" 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> Date: Mon, 16 May 2011 20:11:05 +0200 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6090 X-Y-GMX-Trusted: 0 Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] Jumbo frames and LAN buffers (was: RE: Burst Loss) 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 18:07:21 -0000 Hi Fred, Yes, that's the common topology; However, 802.3x is often used only unidirectional and with very limited effect, but not bidirectional. At least that's the default settings... (I wonder, if both ends of a link are RX, would flow control ever get triggered?) I know a number of deployments, where globally enabling full flowcontrol (as opposed to RX / TX only) lead to fewer packet drops, but also to sometimes massively reduces network bandwidth. This is what I meant when I said you don't want to deploy flow control in a multi-tier network topology because of the congestion tree forming. Best regards, Richard ----- Original Message ----- From: "Fred Baker" To: "Richard Scheffenegger" Cc: "Jonathan Morton" ; Sent: Monday, May 16, 2011 11:49 AM Subject: Re: [Bloat] Jumbo frames and LAN buffers (was: RE: Burst Loss) On May 16, 2011, at 9:51 AM, Richard Scheffenegger wrote: > Second, you wouldn't want to deploy basic 802.3x to any network consisting > of more than a single switch. actually, it's pretty common practice. Three layers, even. People build backbones, and then ring them with workgroup switches, and then put small switches on their desks.=