[Outages-discussion] [EXTERNAL] Re: [outages] Outages Digest, Vol 184, Issue 18

[James Sharp]

On 2/22/24 1:50 PM, Bill Woodcock via Outages-discussion wrote:
>>>> On Fri, 23 Feb 2024 at 02:32, Gershon Chapman via Outages <outages at outages.org> wrote:
>>>> I strongly suspect this to be a BGP issue, and it's going to be a good 24 hours before we see the issue getting any better.
> I haven’t seen anything to suggest that their data network was involved.

As others have said, it unlikely wasn't.  AT&T's temporary work around 
was "Enable WiFi Calling", so that says something happened on the 
cellular network side rather than on the pure IP side.  Of course, that 
didn't help anyone who wasn't conveniently within a wifi network that 
was ipsec tunnel friendly or anyone who didn't have a phone that was 
compatible with AT&Ts wifi calling system (anything older than something 
like a Google Pixel 3 was boned).

Since there was some reports about the issue being in "how calls were 
handed off/over", I'm guessing something went completely bonkers in 
AT&T's LTE Home Location Register database.  If you stayed still, the 
system knew what cell/frequency you were attached to.  If you moved or 
did something that made your local tower have to move you to a different 
frequency/sector/antenna/tower, the HLR completely lost track of you.