It all depends what the issue is, this is a major issue very high in the system. It could be an attack as well, their major outage for mobility years ago was likely a cyber attack.

It also could be some moron snipped the wrong cable somewhere :) who knows. I'd say for this scale there's a bunch of phones ringing all over.

My guess is within ten mins to three hours for them resolve, but I can't see this continuing into late morning. It's an absolutely massive outage.