[EAS] NWS Fun

[Sean Donelan]

On Sat, 11 Aug 2018, Mike McCarthy wrote:
> However, one phone blared the alert tones 5 times over the course of 15
> minutes. It was sitting in the kitchen as the owner was in a studio doing
> a live interview.

You can search for my posts over the last few years about WEA "stuck 
alerts" on cell phones. As far as I can tell, I've seen reports from 
customers using all the major carriers (at&t, sprint, t-mobile, verizon) 
and different models of cell smart phones (android and ios based) based on 
screenshots posted on twitter.

It seems to be one of those distributed problems, which would require 
different parties to cooperate to track down the cause and resolve 
the problem. Instead, all the parties point the fingers at all the other 
parties, and no party has ultimate responsibility.

How its supposed to work:

1. Carriers are supposed to periodically re-broadcast WEA alerts with a 
unique serial number from cell towers in the specified area.  How the WEA 
over-the-air unique serial number is generated and how often the 
re-broadcast occurs varies based on individual carrier tower management 
software and configurations. The over-the-air serial number has a maximum 
of 16-bits, and different than the IPAWS/CAP message ID.

2. Each cell phone is supposed to de-duplicate WEA alerts received with 
the same over-the-air serial number within 24 hours, and only alert the 
user once. However, serial numbers can have geographic scope or network 
scope, which means if the phone connects to different cell towers or 
networks it treats those serial numbers as different. If the user is 
making a phone call when the WEA broadcast is received, the phone is not 
supposed to interrupt the call in progress.

There may also be software bugs in both the cell phone and the carrier 
network management software. Turning the phone off-and-on, may reset the 
bug and stop the duplicate alerts.  Or the phone may forget the previous 
serial numbers and treat all new WEA broadcasts as new alerts.

The cell carriers do not control the cell phone manufacturers' software.

The cell phone manufacturers do not control the cell carriers' software.

FCC and FEMA, shrug, not our problem.

End result: ordinary people have phones that go crazy with duplicate WEA 
alerts.