From: "Jay Hennigan" <jay@west.net>
To: nanog@nanog.org
Sent: Wednesday, June 15, 2022 4:20:40 PM
Subject: Re: Comcast Rolling Outages
On 6/15/22 14:03, Mike Hammett wrote:
> I recently saw this on Facebook:
>
> BREAKING: Some Xfinity/Comcast users are getting a message in the
> Chicago and Springfield, Illinois markets that they are shutting down
> Internet service until 11:15 PM this evening due to overheating
> equipment...
> Update: some areas are doing rolling outages.
Are you sure this isn't a spoof?
> Are rolling outages due to heat something common for ISPs to do? I've
> never heard of it for any of the hundreds of ISPs I've talked to.
Not in my experience. Network gear generates heat. Datacenters are or
should be designed to remove this heat, with appropriate redundancy.
In outside HFC cable plant, there are distributed cable trunk amplifiers
and fiber equipment. These are designed to survive a wide range of
temperatures. A failure in the outside plant distribution would also
take out their cable television offerings.
This outside plant equipment is typically locally powered from the local
utility, with power injected into the coaxial trunk cable. In many cases
there is no battery backup or very little for these trunk amplifiers and
fiber media converters.
If the local power utility is having rolling power blackouts, it's going
to affect cable modem customers in the area of the rolling power
blackouts, many of which won't notice because their power is also out.
Direct fiber customers (GPON, etc.) shouldn't have an issue.
--
Jay Hennigan - jay@west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV
To: nanog@nanog.org
Sent: Wednesday, June 15, 2022 4:20:40 PM
Subject: Re: Comcast Rolling Outages
On 6/15/22 14:03, Mike Hammett wrote:
> I recently saw this on Facebook:
>
> BREAKING: Some Xfinity/Comcast users are getting a message in the
> Chicago and Springfield, Illinois markets that they are shutting down
> Internet service until 11:15 PM this evening due to overheating
> equipment...
> Update: some areas are doing rolling outages.
Are you sure this isn't a spoof?
> Are rolling outages due to heat something common for ISPs to do? I've
> never heard of it for any of the hundreds of ISPs I've talked to.
Not in my experience. Network gear generates heat. Datacenters are or
should be designed to remove this heat, with appropriate redundancy.
In outside HFC cable plant, there are distributed cable trunk amplifiers
and fiber equipment. These are designed to survive a wide range of
temperatures. A failure in the outside plant distribution would also
take out their cable television offerings.
This outside plant equipment is typically locally powered from the local
utility, with power injected into the coaxial trunk cable. In many cases
there is no battery backup or very little for these trunk amplifiers and
fiber media converters.
If the local power utility is having rolling power blackouts, it's going
to affect cable modem customers in the area of the rolling power
blackouts, many of which won't notice because their power is also out.
Direct fiber customers (GPON, etc.) shouldn't have an issue.
--
Jay Hennigan - jay@west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV