nanog mailing list archives

Re: comcast business service


From: Jared Mauch <jared () puck nether net>
Date: Thu, 20 Feb 2014 10:27:37 -0500


On Feb 20, 2014, at 4:08 AM, shawn wilson <ag4ve.us () gmail com> wrote:

A while ago I got Comcast's business service. Semi-idle connections
are get dropped (I haven't really diagnosed this - I just no that it
isn't the client or server but some network in between). However the
second and most obvious issue is that intermittently, the service will
grind to a halt:
--- 8.8.8.8 ping statistics ---
37 packets transmitted, 34 received, 8% packet loss, time 36263ms
rtt min/avg/max/mdev = 398.821/5989.160/14407.055/3808.068 ms, pipe 15

After a modem reboot, it goes normal:
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3003ms
rtt min/avg/max/mdev = 23.181/23.920/24.298/0.474 ms

This seems to happen about once or twice a day. I can't attribute it
to any type of traffic or number of connections. All of the rest of
the network equipment is the same and the behavior persists when a
computer is plugged directly into the modem. I called Comcast and they
said they didn't see anything even when I was experiencing ridiculous
ping times. I tend to think it's an issue with the 'modem' but I'm not
sure what the issue might be or how to reproduce it when asked to if I
tell them to look at it.

Is this on their DOCSIS service?  I've seen the F connector on the back of the CM
introduce noise to the local segment and cause troubles.  If so, you need to have them
dispatch and swap the CM with one that doesn't have this issue.

- Jared



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