From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from uplift.swm.pp.se (swm.pp.se [212.247.200.143]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 59CE921F32F for ; Wed, 24 Sep 2014 22:32:24 -0700 (PDT) Received: by uplift.swm.pp.se (Postfix, from userid 501) id 5AB80A4; Thu, 25 Sep 2014 07:32:21 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=swm.pp.se; s=mail; t=1411623141; bh=uk/8STj8VrsSKY4cQFfFiirMsbh0MPk+zfDbnWCw5Og=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=qfAhbVsBh8VbrU8b5sKB/80GVg2/dOOwYDUg9waz1NF4cyOrVaLvK683N9nYsPRs7 ANpdstHpcg40c9bstoueT0TjO0H7utv/5htC0ufkXtHE0BpGMu35Axx4MYixkeurkF TkOg20qHH9gwtqvZLX/8dI/e6RnUu6/n4h1RJQQk= Received: from localhost (localhost [127.0.0.1]) by uplift.swm.pp.se (Postfix) with ESMTP id 4E51EA3; Thu, 25 Sep 2014 07:32:21 +0200 (CEST) Date: Thu, 25 Sep 2014 07:32:21 +0200 (CEST) From: Mikael Abrahamsson To: David Lang In-Reply-To: Message-ID: References: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) Organization: People's Front Against WWW MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: bloat Subject: Re: [Bloat] I feel an urge to update this 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: Thu, 25 Sep 2014 05:32:53 -0000 On Wed, 24 Sep 2014, David Lang wrote: > The problem is that you don't know what the connectivity is going to be. > (unless you are connecting to the same IP as an existing connection). > Your first few hops are fairly predictable, but after that you have no > idea if you are going to be connecting to a server on a low bandwidth > link, one behind a very congested router, or one with better > connectivity than you have. I am not saying that we *know*, but we might have a pretty good idea. Better than to do the same thing regardless of circumstances. If I know my home connection is 250/50 megabit/s, then there is no reason to treat it like a 0.1 megabit/s connection or a 10GE connection. > using fq_codel on every bottleneck link will make TCP work pretty well > across that entire range of connectivity Well, that'll fix one thing, but for instance the IW4 and IW10 debate. I'm sure IW10 works *great* on a 100/100 megabit/s connection when the server is 10GE connected, but it's less than optimal for a 0.1 megabit/s connection. So why can't the client hint the server that, hmm, I seem to be on a fairly slow connection here, don't send me too much at once? Or it can hint that hey, it seems most times I get pretty large TCP window sizes, so it's ok to start with IW10? -- Mikael Abrahamsson email: swmike@swm.pp.se