Let's call the Nashville bombing today what it is: a domestic terrorism attack on our telecommunications infrastructure.
That much is clear on the basis of facts in evidence even at this early date.

Vehicle shows up in the wee hours.
Parks directly in front of the AT&T transmission building.
6:15-blares music from loudspeakers (gets attention), and verbal warning that there is a bomb. 15-minute 'get clear' countdown commences.
6:30-bomb explodes and devastates AT&T bldg--

and the server farm it houses, along with switches, trunk lines, and much more. AT&T telecomms go offline throughout the Nashville region. Phones down, wifi down. Nashville airport cancels flights because comms are affected by this outage. Even in Murfreesboro, ~50 miles away...

(and other places around the region), there are widespread outages. I discover this personally when we fail to have Christmas dinner as planned. I'm just outside Murfreesboro, but suddenly Grubhub cancels our order: they suddenly can't communicate with local restaurants.

Restaurants can't be reached by phone, and can't access the internet--so companies (and individuals!) trying to do business remotely via AT&T services are SOL for the duration.
We have a lot more to learn about this event, but the above facts are already in evidence. They..