From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f171.google.com (mail-ie0-f171.google.com [209.85.223.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 2FD7F208AD1 for ; Mon, 19 Nov 2012 02:36:49 -0800 (PST) Received: by mail-ie0-f171.google.com with SMTP id 17so1340069iea.16 for ; Mon, 19 Nov 2012 02:36:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=nxIbcxmD0Rmjy5F5i/J7gGwYDjh+l48eIeJcHaXcReI=; b=XcFqIVmZd/DXhBQLIe90B2h1oJ8mCD2qoeJN7Xx9FS5JinswN6TXJucqMMytPvBNU9 Hq6QMA9W/UHE3WxlSVP351Ns9QXVvDAE9F29PSuGopCdHGi1I6Y85I908cPgF+T5QL82 IM+tVdM0B/eIUWizGYHGhUyo82Tq+l9rolYd50M5uztGmEXkMb9tORDjhSAf0puWwUMp yerjh0JZ4EuV9FpNW7li7KXppKuYXmT4tTkt7niGpvx2iaoIOzlRHX9LBsvRHhvJSMvn otJm+fshHmBODXSOeF8rHwlkCswUP4GkbuE09W1A/WadRd7ERSxdlXCKlL9Pf3oqlGjO 61qg== MIME-Version: 1.0 Received: by 10.50.151.138 with SMTP id uq10mr6168866igb.68.1353321408658; Mon, 19 Nov 2012 02:36:48 -0800 (PST) Received: by 10.64.135.39 with HTTP; Mon, 19 Nov 2012 02:36:48 -0800 (PST) In-Reply-To: <81564C0D7D4D2A4B9A86C8C7404A13DA04B32E@ESESSMB205.ericsson.se> References: <81564C0D7D4D2A4B9A86C8C7404A13DA04B32E@ESESSMB205.ericsson.se> Date: Mon, 19 Nov 2012 11:36:48 +0100 Message-ID: From: Dave Taht To: Ingemar Johansson S Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: "bloat@lists.bufferbloat.net" Subject: Re: [Bloat] Skype 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: Mon, 19 Nov 2012 10:36:49 -0000 On Mon, Nov 19, 2012 at 11:27 AM, Ingemar Johansson S wrote: > Hi > > Been a year or so since I read about the inner secrets of Skype so this m= ay be old.. > I would suspect that your Skype session runs over TCP (via a Relay). This= may happen e.g when a firewall blocks UDP. > TCP (possibly in combination with a lossy WiFi connection) is what create= s the high latencies. I recently tried to use both skype and google voice on a concall to the US during the recent strike and riots in barcelona. Power and regular internet were down, so I hacked my way into a local mesh node with a spare directional antenna to make the call. The connection was quite lousy, Skype was unusable. Google voice sort of worked, but exhibited classic symptoms of overbuffering and wifi retries, sometimes playing back seconds of audio at a very high rate, and otherwise dropping out frequently. I got packet traces of the google voice call, but regrettably cannot share them due to the contents of the call. They are "interesting", and if I get a chance I'll write up what I learned. It did inspire me harder, to try and find a rtp based test tool (anyone?), so that the next time I or someone else is in a situation like that, a good analysis can be made. > > /Ingemar > ------------------------------ > > Message: 2 > Date: Sun, 18 Nov 2012 15:57:53 +0100 > From: Michael Welzl > To: bloat > Subject: [Bloat] Skype > Message-ID: <647D57F5-24CE-4006-AD2A-74141C84C3CB@ifi.uio.no> > Content-Type: text/plain; charset=3DUS-ASCII; format=3Dflowed; delsp=3Dye= s > > Hi, > > I have repeatedly noticed that Skype sometimes, in a long conversation in= volving video, can create massive audio delays (in the order of multiple se= conds). This has happened to me in a conversation from a hotel room in the = US to my home in Oslo (where, apologies, I haven't yet looked into de-bloat= ing my modem and access point), and from my office in Oslo to someone else'= s office in the US. > > I'm wondering: was that always due to bloated equipment along the path (i= ncluding the end hosts), or does Skype poorly handle its internal buffers? > > Any experiences? I suppose the way to find out is to run Skype over a ver= ifiably de-bloated path. If, then, the problem never occurs, the fault is w= ith the equipment and not with Skype (and vice versa). > > Cheers, > Michael > > > > ------------------------------ > > Message: 3 > Date: Sun, 18 Nov 2012 08:09:03 -0800 (PST) > From: Alex Burr > To: bloat > Subject: Re: [Bloat] Skype > Message-ID: > <1353254943.93761.YahooMailNeo@web126202.mail.ne1.yahoo.com> > Content-Type: text/plain; charset=3Dus-ascii > > I have noticed delays - although I don't think multiple seconds - but I t= hink that it may be skype trying to make the best of a bad connection. I do= n't have any knowledge of the internals of the skype client, but I suspect = that they take the view that delayed audio is better than incomprehensible = audio - I think I have even heard it actually repeating the last bit of aud= io before a glitch, to give you a better chance to understand the next bit,= and presumably catching up when the opportunity arises. > > So, an experiment to rule out skype might need to use not just a de-bloat= ed path, but one with known packet loss. > > > Alex > > > > ----- Original Message ----- >> From: Michael Welzl >> To: bloat >> Cc: >> Sent: Sunday, November 18, 2012 2:57 PM >> Subject: [Bloat] Skype >> >> Hi, >> >> I have repeatedly noticed that Skype sometimes, in a long conversation >> involving video, can create massive audio delays (in the order of >> multiple seconds). This has happened to me in a conversation from a >> hotel room in the US to my home in Oslo (where, apologies, I haven't >> yet looked into de-bloating my modem and access point), and from my >> office in Oslo to someone else's office in the US. >> >> I'm wondering: was that always due to bloated equipment along the path >> (including the end hosts), or does Skype poorly handle its internal buff= ers? >> >> Any experiences? I suppose the way to find out is to run Skype over a >> verifiably de-bloated path. If, then, the problem never occurs, the >> fault is with the equipment and not with Skype (and vice versa). >> >> Cheers, >> Michael >> >> _______________________________________________ >> Bloat mailing list >> Bloat@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/bloat >> > > > ------------------------------ > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat > > > End of Bloat Digest, Vol 23, Issue 10 > ************************************* > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat --=20 Dave T=E4ht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.= html