Internet service got back online Monday afternoon following an outage that disrupted service in major cities across the United States.

Internet service got back online Monday afternoon following an outage that disrupted service in major cities across the United States.

“I was trying to use Snapchat, just the regular app,” recalled Gwen Doherty, a student at the Rochester Institute of Technology. “And it would not load at all.”

Doherty went from annoyed to alarmed upon learning this particular outage affected systems well beyond Rochester. “I haven't heard of something so widespread before,” she exclaimed. “Giant. Yeah. A little freaky.”

“The internet’s not perfect,” sighed RIT computer student Richard Joerger. “Apparently all it takes is one configuration problem and something goes down."

The problem developed about noon, not in the systems of Comcast, or AT&T, or Spectrum or any local system that provide internet service but rather in the system that provides them internet service, Century Link’s Level 3 internet “backbone.”

A statement from Century Link late Monday said, “Our network experienced a service disruption affecting some customers with IP-based services. The disruption was caused by a configuration error.”

Retired RIT technology manager Nick Francesco explained “configuration error” means some bad computer code mistakenly inserted into the Level 3 system. “…which means some human somewhere fat fingered something and screwed up massive numbers of routers!” Francesco exclaimed. “Clearly, someone was not paying attention.”

That error, he said, effectively cut local service providers off from Level 3 and from each other, but did not necessarily interrupt service within the individual providers’ systems.

The statement from Century Link said the error was addressed and service restored “within approximately 90 minutes” but Francesco said monitoring by the site Down Detector indicates the disruption lasted longer than that. “It took them hours fix the problem,” he said. “Problems travel at the speed of light on the Internet. Fixes, for some reason, are much, much, slower.”