[175756] in North American Network Operators' Group
Re: Comcast Enterprise Fiber Slow Connection Problem from TW Telecom
daemon@ATHENA.MIT.EDU (Zachary Frederick)
Fri Oct 31 15:35:06 2014
X-Original-To: nanog@nanog.org
From: Zachary Frederick <zcfrederick@gmail.com>
In-Reply-To: <CAOQYbjpBGo-XQW+WkLdqqRhCc4Tjayjp=8CDet7PLkjQ7++E9w@mail.gmail.com>
Date: Fri, 31 Oct 2014 15:29:56 -0400
To: John Neiberger <jneiberger@gmail.com>
Cc: NANOG Mailing List <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
I apologize I should have said it starts out about 3 meg max and slows =
to about 400kpbs for most of the transfer.
> On Oct 31, 2014, at 3:27 PM, John Neiberger <jneiberger@gmail.com> =
wrote:
>=20
> With a max bandwidth of 25 Mbps and a 40ms RTT, the max is more like =
14MB/s or 1.75 Mbps.=20
>=20
> =
https://www.switch.ch/network/tools/tcp_throughput/index.html?mss=3D1460&r=
tt=3D80&loss=3D1e-06&bw=3D25&rtt2=3D35&win=3D64&Calculate=3DCalculate =
<https://www.switch.ch/network/tools/tcp_throughput/index.html?mss=3D1460&=
rtt=3D80&loss=3D1e-06&bw=3D25&rtt2=3D35&win=3D64&Calculate=3DCalculate>
>=20
> But that's only if either endpoint is stuck at a 64 KB receive window. =
A quick packet capture would be able to see what was happening. Check =
the TCP setup and make sure that both ends are doing TCP window scaling =
properly.
>=20
> John
>=20
> On Fri, Oct 31, 2014 at 1:02 PM, Pedro Cavaca <pmsac.nanog@gmail.com =
<mailto:pmsac.nanog@gmail.com>> wrote:
> On 31 October 2014 18:32, Zachary Frederick <zcfrederick@gmail.com =
<mailto:zcfrederick@gmail.com>> wrote:
>=20
> > We have been having a problem receiving software releases from our
> > developer. The releases are typically around 1G in size. The =
developer=E2=80=99s
> > connection is a 100m metro fiber with TW Telecom, our connection is =
a 25m
> > Comcast Enterprise Fiber.
> >
> > Our traffic graphs show very little utilization of our connection.
> > Typically on average we are at about 7 meg utilization of our 25.
> >
> > Every other partner that shares in our software development that =
receives
> > the software releases can receive the updates 3-4 times faster than =
we can.
> >
> > Typically we receive the releases at about 3mbps.
> >
>=20
> Are you using an application that uses TCP transport for the transfer?
>=20
> =
https://www.switch.ch/network/tools/tcp_throughput/index.html?mss=3D1460&r=
tt=3D38&loss=3D1e-06&Calculate=3DCalculate&bw=3D100&rtt2=3D80&win=3D64 =
<https://www.switch.ch/network/tools/tcp_throughput/index.html?mss=3D1460&=
rtt=3D38&loss=3D1e-06&Calculate=3DCalculate&bw=3D100&rtt2=3D80&win=3D64>
>=20
> 3Mbps looks about right. Time for a tune up
>=20
>=20
> > I have tried contacting Comcast Enterprise Tech support, however =
I=E2=80=99ve been
> > told that if I run a speed test from my connection and the test runs =
at the
> > speed we are paying for, there is very little they are willing to =
look into.
> >
> > Can anyone check on the Comcast Routers on the Tracert below, or is =
there
> > anything that can be throttling this connection between the two =
connections?
> >
> > Also, our firewall and connection is able to run at the full 25. We =
have
> > no throttling or QOS set to prevent a good connection to our =
developer. For
> > example, we can run a multi-threaded upload, in the middle of the =
night, to
> > Amazon Glacier storage and completely saturate our connection when =
doing
> > so. The firewall and connection is able to handle our full bandwidth
> > capacity during that backup.
> >
> > If there is any other information I can provide to help track this =
problem
> > down, please let me know.
> >
> > Thanks in advance, everyone!
> >
> >
> > Trace Route below:
> >
> >
> >
> >
> > 1 (172.16.150.1) 1.143 ms 1.132 ms 1.122 ms
> >
> >
> > 2 (173.227.204.1) 1.585 ms 1.583 ms 1.574 ms
> >
> >
> > 3 chi2-pr1-xe-0-3-0-0.us.twtelecom.net =
<http://chi2-pr1-xe-0-3-0-0.us.twtelecom.net/> (66.192.245.166) 10.477 =
ms
> > 10.485 ms 10.478 ms
> >
> >
> > 4 x-eth-0-0-4-pe05.350ecermak.il.ibone.comcast.net =
<http://x-eth-0-0-4-pe05.350ecermak.il.ibone.comcast.net/> =
(75.149.230.141)
> > 10.470 ms 10.465 ms 10.457 ms
> >
> >
> > 5 he-2-1-0-0-cr01.350ecermak.il.ibone.comcast.net =
<http://he-2-1-0-0-cr01.350ecermak.il.ibone.comcast.net/> (68.86.86.37) =
10.733
> > ms 10.731 ms he-2-0-0-0-cr01.350ecermak.il.ibone.comcast.net =
<http://he-2-0-0-0-cr01.350ecermak.il.ibone.comcast.net/>
> > (68.86.86.33) 12.146 ms
> >
> >
> > 6 be-10206-cr01.newyork.ny.ibone.comcast.net =
<http://be-10206-cr01.newyork.ny.ibone.comcast.net/> (68.86.86.225) =
33.202 ms
> > 32.144 ms 32.127 ms
> >
> >
> > 7 68.86.91.30 (68.86.91.30) 41.508 ms 41.322 ms 41.599 ms
> >
> >
> > 8 te-0-0-0-1-sur01.greensburg.pa.pitt.comcast.net =
<http://te-0-0-0-1-sur01.greensburg.pa.pitt.comcast.net/> =
(69.139.168.26)
> > 38.196 ms te-0-0-0-3-sur01.greensburg.pa.pitt.comcast.net =
<http://te-0-0-0-3-sur01.greensburg.pa.pitt.comcast.net/>
> > (162.151.21.82) 44.644 ms =
te-0-0-0-0-sur01.greensburg.pa.pitt.comcast.net =
<http://te-0-0-0-0-sur01.greensburg.pa.pitt.comcast.net/>
> > (69.139.195.18) 38.266 ms
> >
> >
> > 9 (107.1.72.98) 39.781 ms 39.785 ms 39.912 ms
>=20
