Ask HN: What causes large-scale ISP outages like Comcast's current One

1 point

10 years ago

This is a part of the world that is so far removed from what I believe reality to be, and I'm wondering if you can help me to understand: what can possibly be responsible for the kinds of outages that Comcast/Xfinity is currently experiencing in the US? [0]

From a network operations standpoint, it feels like it could be something like some kind of faulty metadata/signaling data being propagated all around, but I'm not sure if that's a thing or if my brain invented it.

Can the folks with deeper experience with large-scale ISP operations help shine a light on what can cause these sorts of massive outages/performance issues?

Currently, for example, my cable modem is unable to acquire sync timing synchronization, with QAM and FEC failing to acquire (I don't know what FEC is, and loosely understand QAM). It seems to be scanning large swathes of frequencies to acquire a downstream channel (usually I'm bonded to 8 downstream channels and 4 upstream)

Folks all over the country are reporting the same kinds of failures. Is there something that can cause what appear to be physical failures to acquire an electromagnetic signal propagation on wires from head ends all over the country? Solar activity? Trump protesters? Gamma ray bursts?

I'm lost and want to understand more of this black box.

[0]: http://downdetector.com/status/comcast-xfinity/map/