nanog mailing list archives

Re: PoE, Comcast Modems, and Service Outages


From: Kord Martin <kord () firstnationscable com>
Date: Tue, 29 Mar 2022 16:41:29 -0400

On 2022-03-29 5:46 p.m., Joe Greco wrote:
On Tue, Mar 29, 2022 at 03:42:54PM -0400, Josh Luthman wrote:
There's a certain manufacturer of TDD radio where the CPU clock is at the
same frequency as what Verizon's enodeB will transmit.  Even at miles away,
it can and will cause PIM issues.  Again, don't rule it out.
I'm not ruling anything out, but on the flip side, here in this group
of professional networkers, you'd think lots of people would have piped
up by now with "me too"'s if PoE ghosts killing cable CPE on a 24 hour
cycle were a common thing.

As a small DOCSIS operator, I suppose my sample set isn't large enough to be significant but I can tell you PoE has never been an issue with our modems.

We've had a significantly higher failure rate due to things such as customers driving nails through the modem in an attempt to mount them to walls, and concerned citizens shooting birdshot into our overhead distribution in an attempt to curb the rodent population.

K


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