From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sandelman.ca (relay.cooperix.net [IPv6:2a01:7e00::f03c:91ff:feae:de77]) by huchra.bufferbloat.net (Postfix) with ESMTP id 347ED21F703 for ; Fri, 1 Aug 2014 06:21:01 -0700 (PDT) Received: from sandelman.ca (unknown [209.87.249.16]) by relay.sandelman.ca (Postfix) with ESMTPS id 75CE8220C3 for ; Fri, 1 Aug 2014 09:21:00 -0400 (EDT) Received: from sandelman.ca (quigon.sandelman.ca [127.0.0.1]) by sandelman.ca (Postfix) with ESMTP id 8C402CA0D9 for ; Fri, 1 Aug 2014 00:21:40 -0400 (EDT) From: Michael Richardson To: cerowrt-devel@lists.bufferbloat.net In-reply-to: <2483CF77-EE7D-4D76-ACC8-5CBC75D093A7@gmx.de> References: <13144.1406313454@turing-police.cc.vt.edu> <36889fad276c5cdd1cd083d1c83f2265@lang.hm> <2483CF77-EE7D-4D76-ACC8-5CBC75D093A7@gmx.de> Comments: In-reply-to Sebastian Moeller message dated "Sat, 26 Jul 2014 13:30:08 +0200." X-Mailer: MH-E 8.2; nmh 1.3; GNU Emacs 23.4.1 MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Date: Fri, 01 Aug 2014 00:21:40 -0400 Message-ID: <11000.1406866900@sandelman.ca> Sender: mcr@sandelman.ca Subject: Re: [Cerowrt-devel] Ideas on how to simplify and popularize bufferbloat control for consideration. 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: Fri, 01 Aug 2014 13:21:01 -0000 --=-=-= Content-Transfer-Encoding: quoted-printable On symmetric links, particularly PPP ones, one can use the LCP layer to do echo requests to the first layer-3 device. This can be used to measure RTT and through some math, the bandwidth. On assymetric links, my instinct is that if you can measure the downlink speed through another mechanism, that one might be able to subtract, but I can't think exactly how right now. I'm thinking that one can observe the downlink speed by observing packet arrival times/sizes for awhile --- the calculation might be too low if the sender is congested otherwise, but the average should go up slowly. At first, this means that subtracting the downlink bandwidth from the uplink bandwidth will, I think, result in too high an uplink speed, which will result in rate limiting to a too high value, which is bad.=20=20 But, if there something wrong with my notion? My other notion is that the LCP packets could be time stamped by the PPP(oE) gateway, and this would solve the asymmetry. This would take an IETF acti= on to make standard and a decade to get deployed, but it might be a clearly measureable marketing win for ISPs. =2D-=20 Michael Richardson =2Don the road- --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBAgAGBQJT2xXSAAoJEKD0KQ7Gj3P2jwAH/2WsRpJco2DoeUqQniEgZx4C tgZVgR/gRiN3f0bA5qCESwGJybDKF+YOmgImeAGa9SZli/kRQ8E3fX348ngbrpD9 ASRIgklVy7BNu2QRwBSEd7ELS3nnUUQtQRlOqg8ePjxJEg7w9cmSf+fS+O5UIaSb uolln4WY8funKA0XQtk9MWzAjNXZyvh0EKROcFybb4gCC9aq3kXCf9bYYBn5dIVR YagNPfVlo94PI6UC9BbofqTP6c4ZMomgIOtc+aT/Sndr6NJL6awXUupJlliQrHfY Fdvi8WhB4VVPUQ32RDFaKH87vMOIOS+sikZaBy36HwCeVqsHHzuNW4TUebqt2CU= =ClLT -----END PGP SIGNATURE----- --=-=-=--