A Comcast outage is hitting users across the US

WIDESPREAD INTERNET OUTAGES around the United States on Friday afternoon quelled productivity and sent irate customers to Twitter to complain. Comcast and Xfinity suffered the biggest service interruptions across its internet, cable, and landline products. The company, which has more than 29 million business and individual customers, said on Friday that the outages stemmed from fiber optic cables at two internet infrastructure companies that were cut or otherwise disrupted.
Like virtually all internet providers, Comcast relies on a combination of its own fiber-optic infrastructure and that of other partner companies to seamlessly route data around the world. Comcast, the nation's largest broadband provider and one of the largest pay-TV providers, had a nationwide outage of some services Friday.
The Philadelphia-based company said it was aware Friday afternoon some of its TV, broadband and telephone customers across the U.S. were affected. The underlying physical backbone of the internet is surprisingly fragile, and failsafes don't always work. For example, in November, a tiny misconfiguration error at Level 3 caused outages around the US. And a digital attack on the internet infrastructure company Dyn famously caused major outages in 2016 because they were targeted at destabilizing one of the internet's underlying routing protocols.

"We are profoundly and globally dependent on a fundamentally fragile infrastructure," says Roland Dobbins, a principal engineer at the DDoS and network-security firm Arbor Networks, which monitors global internet operations. "Some redundancies exist, but many times they don't."

By Friday evening, Comcast service had come back for many customers. But the underlying message should resonate: The internet can be frailer than you'd think, and sometimes all it takes to shut it down is a couple of cuts.