From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from jabiru.ens-lyon.fr (jabiru.ens-lyon.fr [140.77.51.2]) by huchra.bufferbloat.net (Postfix) with ESMTP id 68426201253 for ; Tue, 2 Jul 2013 04:08:47 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by jabiru.ens-lyon.fr (Postfix) with ESMTP id 070A51EB284; Tue, 2 Jul 2013 13:08:45 +0200 (CEST) X-Virus-Scanned: by amavisd-new-2.6.4 (20090625) (Debian) at ens-lyon.fr Received: from jabiru.ens-lyon.fr ([127.0.0.1]) by localhost (jabiru.ens-lyon.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id i0uHbUpYx-8R; Tue, 2 Jul 2013 13:08:44 +0200 (CEST) Received: from localhost (rev20.vpn.fdn.fr [80.67.179.20]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client did not present a certificate) by jabiru.ens-lyon.fr (Postfix) with ESMTPSA id 34F3C1EB27C; Tue, 2 Jul 2013 13:08:44 +0200 (CEST) Date: Tue, 2 Jul 2013 13:08:38 +0200 From: Baptiste Jonglez To: Mikael Abrahamsson Message-ID: <20130702110838.GD24656@ens-lyon.fr> References: <20130701164607.GB12090@ens-lyon.fr> <871u7hesmm.wl%jch@pps.univ-paris-diderot.fr> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="VMt1DrMGOVs3KQwf" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Mailman-Approved-At: Tue, 02 Jul 2013 07:14:02 -0700 Cc: bloat@lists.bufferbloat.net, babel-users@lists.alioth.debian.org, Juliusz Chroboczek Subject: Re: [Bloat] [Babel-users] RTT stability inside a GRE tunnel 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: Tue, 02 Jul 2013 11:08:47 -0000 --VMt1DrMGOVs3KQwf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jul 02, 2013 at 06:48:14AM +0200, Mikael Abrahamsson wrote: > On Tue, 2 Jul 2013, Juliusz Chroboczek wrote: >=20 > >Anybody seen anything similar? >=20 > I don't know if this is the cause, but older gear from Extreme > Networks (their end-of-90ties and beginning of 2000s), will do ICMP > in slow-path when routing (even packets going through the device) and > "everything else" in fast-path. This could cause latency spikes and > PDV approximately similar to what's seen in the picture. This looks like a plausible explanation, thanks. They may not be the only router make to exhibit this behaviour. Is there a reason for this slow-path routing of ICMP? I've seen routers applying some kind of rate-limiting to ICMP packets, but as far as I know, it's only limited to ICMP packets originating from the router. --VMt1DrMGOVs3KQwf Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (GNU/Linux) iQIcBAEBAgAGBQJR0rS2AAoJEAwdk2Chmk9bxZQQAIZ7adJm6pUiRKuKt8XLQeN6 F0KVIKlm573V+eOXzV8+nlJ3sBDgAfKLnucRRaK1m70S1vVrxfZQPKkqsaT5hFoq x+ZVk9x16w6pZ+cOpE+6o22yuzWoX1PhcV91aZ+ZUy8K6K79Ufv5ZKfiwSx/dttd EqKdxEikdyZ2AnvGdcSq2pQDYdG5lrWVPxsdkaL58vbTSPM1qXkrb90gnCbvVKeV 15rSB1/88MCkEtow2YO3fDKkHskszUNmCmLTZ08VMFNfVCoZ0lyd/En3a0vOCF2l UvSPkrDlnDxMJ4AHxVBugBSbxTgm+pvD0Lfvm4R1C3UAnLJg/L95QhZaeHVWb7bs cerTmSVZDHwOLAGJD58LFB7XHqVVYM4LWoCpk7IjnBYLfxfe274QN3wI5+OolOTX TLlkeV4ppLQZuQT1FWi+zvIRN05jJw4kxqJbZOqyF4aZY1AmTgFRA05/Pwz18fa+ jaf2VUpR8qrTlqbnLkJpHjBDmWEf/zfKm7pLxhxvscgxS4tjs5ALoen5Q+0kazyz Oa+CPIraPN2n2TFVh1yfHXK2SWYvhIC5opT2IN/RQIrHmeM7miXU4BHwoMTKVh1c gQg5mIX4zF7fVF8zvbNfNDshYp0lxUE2A18DjUrFiLtGDErOIJy/zvdDtHP3In4s ZYv0esjgi5PBa6GwAvDB =du32 -----END PGP SIGNATURE----- --VMt1DrMGOVs3KQwf--