From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tuna.sandelman.ca (tuna.sandelman.ca [IPv6:2607:f0b0:f:3::184]) by huchra.bufferbloat.net (Postfix) with ESMTP id 33A4021F212 for ; Thu, 4 Jul 2013 06:52:24 -0700 (PDT) Received: from sandelman.ca (obiwan.sandelman.ca [IPv6:2607:f0b0:f:2::247]) by tuna.sandelman.ca (Postfix) with ESMTP id 3D6E72018B; Thu, 4 Jul 2013 10:56:57 -0400 (EDT) Received: by sandelman.ca (Postfix, from userid 179) id 086C0A902A; Thu, 4 Jul 2013 09:51:14 -0400 (EDT) Received: from sandelman.ca (localhost [127.0.0.1]) by sandelman.ca (Postfix) with ESMTP id EB869636AD; Thu, 4 Jul 2013 09:51:14 -0400 (EDT) From: Michael Richardson To: Mikael Abrahamsson In-Reply-To: References: X-Mailer: MH-E 8.2; nmh 1.3-dev; GNU Emacs 23.4.1 X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m Sender: mcr@sandelman.ca Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] happy 4th! X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Jul 2013 13:52:26 -0000 Mikael Abrahamsson wrote: > On Wed, 3 Jul 2013, Dave Taht wrote: >> Suggestions as to things to test and code to test them welcomed. In > I'm wondering a bit what the shallow buffering depth means to > higher-RTT connections. When I advocate bufferbloat solutions I usually > get thrown in my face that shallow buffering means around-the-world > TCP-connections will behave worse than with a lot of buffers > (traditional truth being that you need to be able to buffer RTT*2). huh? The end points might need more buffers to receive more packets (some of which might be out of order), but the intermediate routers need nothing. None of the bufferbloat stuff reduces the receive buffers of an end-point. On long latency links, (the worse being geosynchronous satellite), the link *itself* stores data. (a historical exploitation of this: https://en.wikipedia.org/wiki/Delay_line_memory ) So, who is saying this to you, and what exactly do they think bufferbloat is about? -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works | network architect [ ] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [