What is Fastly and why did it just take a bunch of major websites offline?
The logo of US cloud computing services provider Fastly is seen on a smartphone screen. Pavlo Gonchar | SOPA Images | LightRocket via Getty Images  A slew of major websites including Amazon, Reddit and news publishers like The New York Times were affected by a massive internet outage Tuesday. The outages started at around 6 a.m. ET, with users reporting they were receiving error messages including "Error 503 Service Unavailable" and "connection failure" when attempting to visit various websites. The sites  which also included the U.K. government website  are now mostly back online. Early reports have pointed the blame at Fastly, an American cloud computing services firm. Fastly's status page said Tuesday morning that it was investigating a technical issue. It now says the issue has been resolved. Shares of Fastly were down in U.S. premarket trading, but rose as much as 6% as markets opened for trading Tuesday. Fastly operates what's known as a content delivery network, or CDN. CDNs are networks of servers and data centers distributed around the world that allow for the transfer of assets needed for loading internet content. The company describes its technology as an "edge cloud" platform, which essentially means it places its infrastructure closer to the location where it's needed to offer users faster response times. Fastly's tech is designed to counter common causes of online outages, such as distributed denial-of-service attacks which overwhelm a website with a sudden wave of traffic. "The intention of CDNs is to route (or distribute) internet traffic and services through 'nodes' in order to balance the load of traffic, prevent bottlenecks and result in high availability and faster content delivery," said Mark Henry, director of data protection and cyber security at global law firm DWF. "Requests for content are directed by an algorithm, for instance the algorithm might direct the traffic so that it routes through the most available or highest performing node, or so that the traffic takes the fastest network route to the requestor." Henry said that some of the organizations affected by the outage were reverting to non-CDN distribution schemes to get their sites back up and running, but that this could result in a "slower than normal" experience for users.