Outages in Indiana, Kentucky, Tennessee and Alabama potentially caused by AT&T backhaul network

All four major U.S. wireless carriers – Verizon Wireless, AT&T Mobility, Sprint and T-Mobile US – experienced extensive network outages yesterday, apparently due to a hardware failure on AT&T’s network.

RCR Wireless News first reported outages affecting major metros on the East and West coasts, which ultimately shifted to cover a large area including Indiana, Tennessee, Kentucky and part of Alabama.

Based on reports from the carriers, service was restored around 9 p.m. Eastern time.

Re/code, siting telecom industry insiders, reported that, “AT&T is the dominant landline provider for the region, and all the major cellular providers use its networks for backhaul – that is, helping transport the data once it leaves their collection of cellular towers.”

Around 10 p.m. Tuesday, AT&T tweeted, “Wireless and wireline service has been restored for all customers in parts of the Southeast affected by a hardware-related network issue.”

Verizon, at about 8 p.m., tweeted, “Verizon engineers worked with our vendors to identify and resolve the issue and service was restored.”

Sprint also weighed in: “Good news, vendor issues impacting wireless service in the [Southeast] have been resolved.”

A spokesman for the Kentucky Public Service Commission, speaking to Kentucky.com, said the issue was based on “interconnection and roaming arrangements. Carriers have agreements to route calls over each others’ facilities, so if a major cable or other facility is damaged, it affects more than just the owner/operator of that facility.”