AT&T statement says nearly all services have been restore in Nashville as
of Monday, 5pm CST
They are working on permanent repairs.
https://about.att.com/pages/disaster_relief/nashville.html
AT&T's Network Disaster Recovery group faces management questions nearly
every year to justifying their budget. While no one wants disasters,
business continuity has to be part of the business. There are also mutual
aid agreements between companies, but I don't know how many were invoked
for this incident.
https://about.att.com/ecms/dam/pages/disaster_relief/NDR_edited_04.22.19.pdf