FCC Seeks Comment on Effects of June 15 T-Mobile Outage

On June 15, 2020, T-Mobile suffered a substantial outage that prevented customers from making calls, receiving calls, and in some cases, sending text messages over T-Mobile’s Voice-over LTE (VoLTE) network. According to social media reports, the outage also affected 911 calling for T-Mobile customers. T-Mobile explained in a public statement that this outage was caused by “a leased fiber circuit failure from a third party provider in the Southeast.”  When this circuit overloaded, according to T-Mobile, it “resulted in an IP traffic storm that spread from the Southeast to create significant capacity issues across the IMS (IP Multimedia Subsystem) core network that supports [T-Mobile’s] VoLTE calls.”

The Public Safety and Homeland Security Bureau is conducting an investigation into this outage given the large area affected and the critical importance of dependable and resilient 911 service throughout the US. To permit a thorough and accurate analysis of this outage, the Bureau has opened a public docket and invites interested parties to provide all relevant information concerning the causes, effects, and implications of this outage. We seek comment on the impact of these outages from the perspective of affected public safety entities, as well as state and local governments.