From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-21-ewr.dyndns.com (mxout-060-ewr.mailhop.org [216.146.33.60]) by lists.bufferbloat.net (Postfix) with ESMTP id 3B49F2E0632 for ; Sun, 20 Mar 2011 15:45:48 -0700 (PDT) Received: from scan-22-ewr.mailhop.org (scan-22-ewr.local [10.0.141.244]) by mail-21-ewr.dyndns.com (Postfix) with ESMTP id 439D61A00 for ; Sun, 20 Mar 2011 22:45:47 +0000 (UTC) X-Spam-Score: -1.0 (-) X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 209.85.215.43 Received: from mail-ew0-f43.google.com (mail-ew0-f43.google.com [209.85.215.43]) by mail-21-ewr.dyndns.com (Postfix) with ESMTP id 65D7F1340 for ; Sun, 20 Mar 2011 22:45:42 +0000 (UTC) Received: by ewy20 with SMTP id 20so1633546ewy.16 for ; Sun, 20 Mar 2011 15:45:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to:x-mailer; bh=5AR21kMUP+maKO53cIrXh6MutcAmGg23gCemn8trMAQ=; b=v5QD55F7cK3qYULyHggKNlALhSuHuerKpOmwr5nQbwRFnZzFbd2ACXYjeJxh+dfkQo WMkDesZjTUim84UOJe+5O0ZHMrV6paU4vrX6yGaz6WuN7HknNAiSO/X8/288JudjP7e/ AUDF3Tb8HaGgEl9qCiRQZ35Sy06y7PuLphJwI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer; b=g6FdXpbCGQkqxaqFKtBL3m069VAgiZWG6+L3ozaZb3HV45sxzr+0buy5RTR8BKY/v/ HiclbDl77idyT1n/C78G/7F6sBPekGMwRmIxMjzZ4yzwR+mXYSO3/t1tde8JXDAgHe0o ikxK5HYmLWrtP6eiNglbk45hIGQw86g1Q0IZQ= Received: by 10.213.25.212 with SMTP id a20mr1151552ebc.106.1300661141755; Sun, 20 Mar 2011 15:45:41 -0700 (PDT) Received: from [192.168.239.42] (xdsl-83-150-84-172.nebulazone.fi [83.150.84.172]) by mx.google.com with ESMTPS id x54sm1495042eeh.19.2011.03.20.15.45.40 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 20 Mar 2011 15:45:41 -0700 (PDT) Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: text/plain; charset=us-ascii From: Jonathan Morton In-Reply-To: Date: Mon, 21 Mar 2011 00:45:39 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <909F3A19-C7DA-4E38-9BB0-A2EA5F625B7F@gmail.com> References: <4D7F4121.40307@freedesktop.org><20110315175942.GA10064@goldfish><1300212877.2087.2155.camel@tardy><20110315183111.GB2542@tuxdriver.com><29B06777-CC5F-4802-8727-B04F58CDA9E3@gmail.com><20110315205146.GF2542@tuxdriver.com><219C7840-ED79-49EA-929D-96C5A6200401@gmail.com><20110315151946.31e86b46@nehalam><1300228592.2087.2191.camel@tardy><1300229578.2565.29.camel@edumazet-laptop><87fwqo54n7.fsf@cruithne.co.teklibre.org><823E2A7B-4F46-4159-8029-BD3B075CC4CE@gmail.com><87bp1b6fo0.fsf@cruithne.co.teklibre.org><87bp1b4yh4.fsf@cruithne.co.teklibre.org> <7480559F-1F3B-4CE5-939F-FD9FD3E68E52@cisco.com> To: david@lang.hm X-Mailer: Apple Mail (2.1082) Cc: Stephen Hemminger , bloat Subject: Re: [Bloat] Random idea in reaction to all the discussion of TCPflavours - timestamps? 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: Sun, 20 Mar 2011 22:45:48 -0000 On 21 Mar, 2011, at 12:18 am, david@lang.hm wrote: >> 0) Buffering more than 1 second of data is always unacceptable. >=20 > what about satellite links? my understanding is that the four round = trips to geosync orbit (request up, down, reply up down) result in = approximatly 1 sec round trip. That is true, but it doesn't require more than a full second of = buffering, just lots of FEC to avoid packet loss on the link. At those = timescales, you want the flow to look smooth, not bursty. Bursty is = normal at 100ms timescales. What I've heard is that most consumer satellite links use split-TCP = anyway (proxy boxes at each end) thus relieving the Internet at large = from coping with an unusual problem. However, it also seems likely that = backbone satellite links exist which do not use this technique. I heard = something about South America, maybe? Anyway, with a 1-second RTT, the formula comes out to max 1 second of = buffering because of the clamping. - Jonathan