PoE, Comcast Modems, and Service Outages

Kord Martin kord at firstnationscable.com
Tue Mar 29 20:41:29 UTC 2022

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.


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