From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x233.google.com (mail-wm0-x233.google.com [IPv6:2a00:1450:400c:c09::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id C22F53B2A2 for ; Thu, 8 Dec 2016 21:35:09 -0500 (EST) Received: by mail-wm0-x233.google.com with SMTP id g23so6385325wme.1 for ; Thu, 08 Dec 2016 18:35:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:from:date:message-id:subject:to; bh=HNHmJSnteS5GZKgmffGG2THldg2OfjCxP3xESTclLqU=; b=rU62BTW7uLIGjwIORur+zXIYFOaFwMUpQ8O0usrUer3yWjj9CQ2vGiAfuajNCKzv5y XfOibY7nc940tdcsofybJx7F1gP7/9HPgim+nMTcgZzlbWvK9eosS7MWED7XQCklddSA A3niG6ykVhEET0wzY/oKD9jtjLxphd7v1m9Xg/wix4KY6+YMuLm3dWMVvReDzNo/JuwM suP2ymwPGeBiFyEO0ya7qmZhDxJ/XuvjCbCK+Z8CFN84J7KjiD5h3p9+A0VNvGaKpxn4 Rybfc4fRCsIDqNpuJetwxys0kwrPUZ7uGija3fh3Q2nG8oYhYMrsaTYdPxdm4e1A9phB FvRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:from:date:message-id:subject :to; bh=HNHmJSnteS5GZKgmffGG2THldg2OfjCxP3xESTclLqU=; b=NzJ3qvp0SI6oWCMIT3wgyIFtO8Ld6jeTs2yEYMiLjGN/u3TCXQaKhFhktJgebw56aI I2VSxoxPQ20ukn+h9aa54hUQV/3JdfZuwRd3+WSTd0ujUR+SwBLN4sQmqzX/e0yY0+2k IgbtxPpyWqkVqqZNTQXLBKpHHgRCTtodBWOKOfdcOsqPZ5Wp+KoCzefg9+pw9IPxnWC9 g6SZCLUCMlPmtWZDFwWsulEQViVvDMrBc4A5CFKPoEk6ZyD17zCHKEOUfn9k/NL1vxGU 8hkZ0yZVEmfGyZ8D8Qu9Ye8WPt/KPkrjRbqqeX0NpizeLHCeJeA+mFdIpBNiDBNAJA/0 8fWg== X-Gm-Message-State: AKaTC00raJx18m+dCn7uz9KX+BYhJ3iJ+Nh0ak2Q8x7W2rsxQv2XuR909jdxrk6+T+nAraOilp77h2tYLu7iZQ== X-Received: by 10.28.141.18 with SMTP id p18mr4358169wmd.31.1481250908620; Thu, 08 Dec 2016 18:35:08 -0800 (PST) MIME-Version: 1.0 Sender: justinbeech@gmail.com Received: by 10.28.16.195 with HTTP; Thu, 8 Dec 2016 18:34:28 -0800 (PST) From: jb Date: Fri, 9 Dec 2016 13:34:28 +1100 X-Google-Sender-Auth: sIgZIs_AuNSz6h3jIHPW_rEgCN0 Message-ID: To: bloat Content-Type: multipart/alternative; boundary=001a114700fa3b4ea50543309afc Subject: [Bloat] What does cablelabs certification actually do? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Dec 2016 02:35:09 -0000 --001a114700fa3b4ea50543309afc Content-Type: text/plain; charset=UTF-8 http://www.cablelabs.com/specs/certification/ So a number of our users have ganged together to share information and discovered that Puma6 chipset based cable modems all seem to have a very bad flaw. Whether this flaw is fixable in firmware isn't known. The only company initially participating in the discussion - Arris - has gone a bit quiet. We built a tiny tool to identify whether a cable modem has the issue: http://www.dslreports.com/front/puma6.html The distribution of latencies for a puma6 modem is terrible, stretching over 100ms and beyond often as high as 500ms. This appears to be some kind of systemic packet loss or delay involving small packets and while it doesn't influence speed over an established connection it screws up DNS lookups and short TCP transactions. So its rather a strange issue but very irritating for any owner of these new modems until it gets fixed. The modem / chipset is increasingly widely used so we got the register to warn about the issue, I think they are going to do a new article next week: http://www.theregister.co.uk/2016/12/03/intel_puma_chipset_firmware_fix/ Anyway while looking at this data and the number of these Puma6 driven modems out there now, I wondered how it got certified! And then wondered why certification can't also include verification for correctly sized buffers as well? --001a114700fa3b4ea50543309afc Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
= http://www.cablelabs.com/specs/certification/

So= a number of our users have ganged together to share information and discov= ered that Puma6 chipset based cable modems all seem to have a very bad flaw= . Whether this flaw is fixable in firmware isn't known. The only compan= y initially participating in the discussion - Arris - has gone a bit quiet.=

We built a tiny tool to identify whether a cable = modem has the issue:

The distribution of latencies for a puma6 modem is terrible, stretc= hing over
100ms and beyond often as high as 500ms. This appears t= o be some
kind of systemic packet loss or delay involving small p= ackets and while it doesn't influence speed over an established connect= ion it screws up DNS lookups and short TCP transactions. So its rather a st= range issue but very irritating for any owner of these new modems until it = gets fixed.

The modem / chipset is increasingly wi= dely used so we got the register to warn about the issue, I think they are = going to do a new article next week:
Anyway while looking at this data and the number of these Puma= 6 driven modems out there now, I wondered how it got certified!
<= br>
And then wondered why certification can't also include ve= rification for correctly sized buffers as well?
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