WASHINGTON, August 19, 2019—The Federal Communications Commission today released a report detailing the cause and impact of a nationwide CenturyLink network outage that occurred last December, along with recommendations to help prevent similar outages from occurring in the future.

“This massive ‘sunny day’ outage was completely unacceptable and impacted millions of customers across the country. Americans expect and deserve reliable phone and broadband service—especially the ability to call 911,” said FCC Chairman Pai. “It’s important for communications providers to take heed of the lessons learned from this incident. I also thank the Public Safety and Homeland Security Bureau for its thorough investigation and recommending next steps to promote network reliability.”

Beginning on December 27, 2018, CenturyLink experienced an outage on its fiber network that lasted for almost 37 hours. As described in today’s report, the outage was caused by an equipment failure that was exacerbated by a network configuration error. The outage affected communications service providers, businesses customers, and consumers who relied upon CenturyLink’s transport services, which route communications traffic from various providers to locations across the country. The outage resulted in extensive disruptions to phone and broadband service, including 911 calling. As many as 22 million customers across 39 states were affected, including approximately 17 million customers across 29 states who lacked reliable access to 911. At least 886 calls to 911 were not delivered.

Today’s report outlines lessons learned from the incident and identifies specific network reliability best practices that, if implemented, could have prevented the outage, or at least mitigated its effects. These include:

· Turning off or disabling system features that are not in use;

· Including in network monitoring memory and processor utilization alarms that are regularly audited to ensure functionality and evaluated to improve early detection and calibration; and

· Having standard operating procedures for network repair that address cases where normal networking monitoring procedures are inoperable or otherwise unavailable.

Among next steps, the Bureau will engage in stakeholder outreach to promote best practices and contact other major transport providers to discuss their network practices. In addition, the Bureau will offer its assistance to smaller providers to help ensure that our nation’s communications networks remain robust, reliable, and resilient.