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70,000 ATT customers are without service across the US
(arstechnica.com)
This is a most excellent place for technology news and articles.
It was BGP
"According to an industry source who spoke on the condition of anonymity, the root of the outage appeared to be related to how cellular services hand off calls from one network to the next, a process known as peering. "
https://www.cnn.com/2024/02/22/tech/att-cell-service-outage/index.html