nanog mailing list archives
Re: PoE, Comcast Modems, and Service Outages
From: Joe Greco <jgreco () ns sol net>
Date: Tue, 29 Mar 2022 16:00:05 -0500
On Tue, Mar 29, 2022 at 03:07:47PM -0400, Josh Luthman wrote:
We've routinely seen where lines not even connected to the same circuit in any way (ie an OTA antenna coax line and cat5 POE) cause issues with one another. As much as we would all love to have a perfect line in the sand, there isn't. Don't rule anything out until the issue is resolved. As someone that sees this in the field and watches people simply hate on someone because there's a frustrating situation, it's worth taking a breath before too upset.
You can run cable lines next to A/C wiring and get problems too. Or ethernet lines next to A/C wiring. That does not justify wild claims about PoE such as what this tech was making, and until someone shows me a graph of "PoE buildups" observable via SNMP or whatever the cable company is using to graph trends, it seems pretty clear that this is a bogus answer. There's a lot of difference between "we observed this very specific kind of interference related to PoE in a particular circumstance" and the crazy generalizations being made by the tech. Asking to please make sure your switch is grounded properly? That'd be good. Asking for PoE to be disabled on the port? Yeah fine. Suggesting separation of cables? Sure. Checking for proper grounding of the ground block (on the cable inlet)? Sure. There's room for things to happen. I'm all for investigating with an open mind, but I draw the line at crazy. Given that so much of the world works on PoE, it seems like the other potential resolution would be to note that there's an implication here by the tech that Comcast's hardware is standards noncompliant and ask them what they plan to replace their cheap CPE with. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.'"-Asimov
Current thread:
- PoE, Comcast Modems, and Service Outages Aaron de Bruyn via NANOG (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Joe Greco (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Josh Luthman (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Joe Greco (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Josh Luthman (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Joe Greco (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Aaron C. de Bruyn via NANOG (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Kord Martin (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Matt Ertle (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Sabri Berisha (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Grant Taylor via NANOG (Mar 30)
- Re: PoE, Comcast Modems, and Service Outages Aaron de Bruyn via NANOG (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Grant Taylor via NANOG (Mar 30)
- Re: PoE, Comcast Modems, and Service Outages Kord Martin (Mar 30)
- Re: PoE, Comcast Modems, and Service Outages Josh Luthman (Mar 29)
- Re: PoE, Comcast Modems, and Service Outages Joe Greco (Mar 29)