PoE, Comcast Modems, and Service Outages

Tue Mar 29 20:25:57 UTC 2022

On 3/29/22 11:21, Aaron de Bruyn via NANOG wrote:
> I just got off the phone with a Comcast tech, and wanted to double-check 
> my sanity.
> 
> Somehow in the last 6 months I've managed to reach the exact same rep 
> twice when dealing with an outage or a degraded service event.
> 
> I asked him to remotely reboot the modem because there was high packet loss.
> 
> Both times I've talked with him, he noted the high packet loss, started 
> to reboot the modem, and then asked me point-blank if we had any PoE 
> switches on our network.
> 
> When I said "yes", he said I needed to disable PoE because it messes 
> with the Comcast modems and he can see "buildups" in his graphs that 
> show power is "leaking" to the Comcast modem every 24 hours.

Obligatory relevant xkcd: https://xkcd.com/806/

-- 
Jay Hennigan - jay at west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV