From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ia0-x233.google.com (ia-in-x0233.1e100.net [IPv6:2607:f8b0:4001:c02::233]) (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 C0C9A21F175 for ; Sun, 27 Jan 2013 23:41:39 -0800 (PST) Received: by mail-ia0-f179.google.com with SMTP id x24so3795323iak.10 for ; Sun, 27 Jan 2013 23:41:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:date:message-id:subject:from:to :content-type; bh=YpUBDuBvBHKVlRfF2Qe6obn9xMglFZJhDAWRzTSrBeE=; b=ak5COugUN7DYD1/JkpQfY0A+vMCXm/lsrcmjNUKRFlescH8PXLrqzjWZRZV6X+fNMQ GjKrhio9UseYH+jZxQ1xoUlRznZe2jTj/nDUXF4ZkhAX2o62Kn4+n/kFREd9miF+t5zm 6kWQtiFxQ/xMKjLdij86hOgxIP21JzC+aulmrgYBPaEWecsVavg1ESH26Iv7xMc496Pc ygno2i9PXWMn3+tcq1gUH/4gUGNgPHDTpHTrg7fus2GdrGqKuQLhZ81PaeHQPc9CXFb5 e3CZQiqtQIRcuqcBg0py1TQbpq4nAbXssrjv52DaiXPGy+xGmqURYAg14lQ4+R2XqzSK iU2g== MIME-Version: 1.0 X-Received: by 10.50.196.164 with SMTP id in4mr4233396igc.86.1359358897913; Sun, 27 Jan 2013 23:41:37 -0800 (PST) Received: by 10.64.135.39 with HTTP; Sun, 27 Jan 2013 23:41:37 -0800 (PST) Date: Sun, 27 Jan 2013 23:41:37 -0800 Message-ID: From: Dave Taht To: Robert Bradley , Felix Fietkau , cerowrt-devel@lists.bufferbloat.net Content-Type: multipart/alternative; boundary=14dae93405c93b7ea804d4546832 Subject: [Cerowrt-devel] deployed some cero this weekend, chasing checksums 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: Mon, 28 Jan 2013 07:41:40 -0000 --14dae93405c93b7ea804d4546832 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable I have been debugging some weirdness for a while. You might want to do some captures on the latest cero and look at checksums. An unreasonably high number of checksum issues seem to be happening, but there doesn't appear to be a whole lot of pattern to it, as yet. I will simplify. I pinged locally and 8.8.8.8 and surfed the web, and a symptom is that some other routers can't ping sometimes nor access much of the internet beyond the gateway. They can always reach the gateway. in the interim, the topology on this capture are 172.30.102.17 - laptop via ethernet to 172.20.102.1 - cerowrt 3.7.4-4 via ethernet to 172.20.6.1 - ubnt 3.3.8-26 via mesh to 172.20.142.11 - ubnt 3.7.4-4 via ethernet to * 192.168.100.1 - cerowrt 3.7.2 capture point (yes, updating that) 10.0.10.1 - comcast box (yes, double nat, fixing that) I took a capture on the se00 interface tcpdump -i se00 -w/tmp/yurt.cap host 172.20.102.17 and stuck that capture there: http://snapon.lab.bufferbloat.net/~d/yurt/yurt.cap and then looked at it with wireshark with this filter ip.checksum_bad =3D=3D 1 and scratched my head at the error rate (about 1%) and the pattern (lack thereof) I will simplify in the mroning --=20 Dave T=E4ht Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html --14dae93405c93b7ea804d4546832 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

I have been debugging some weirdn= ess for a while. You might want to do some captures on the latest cero and = look at checksums.

An unreasonably high number of checksum issues s= eem to be happening, but there doesn't appear to be a whole lot of patt= ern to it, as yet.

I will simplify. I pinged locally and 8.8.8.8 and surfed the web, and a= symptom is that some other routers can't ping sometimes nor access muc= h of the internet beyond the gateway. They can always reach the gateway.=A0=

in the interim, the topology on this capture are

172.30.102.17 -= laptop via ethernet to
172.20.102.1 - cerowrt 3.7.4-4 via ethernet to172.20.6.1 - ubnt 3.3.8-26 via mesh to
172.20.142.11 - ubnt 3.7.4-4 vi= a ethernet to
* 192.168.100.1 - cerowrt 3.7.2 capture point (yes, updating that)
10.0.= 10.1 - comcast box (yes, double nat, fixing that)

I took a capture o= n the se00 interface

tcpdump -i se00 -w/tmp/yurt.cap host 172.20.102= .17

and stuck that capture there:

http://snapon.lab.bufferbloat.net/~d/yurt/yurt= .cap

and then looked at it with wireshark with this filter

ip.checksum_bad =3D=3D 1

and scratched my head at the error rate= (about 1%) and the pattern (lack thereof)

I will simplify in the mr= oning

--
Dave T=E4ht

Fixing bufferbloat with cerowrt: h= ttp://www.teklibre.com/cerowrt/subscribe.html=20 --14dae93405c93b7ea804d4546832--