Major Websites Knocked Offline

Several high-profile websites went offline for around an hour this week thanks to problems with a content delivery network (CDN). The disruption to sites like the New York Times, Amazon and Reddit was a reminder of weak points in the way the Internet works today.

The problem also affected CNN, the United Kingdom's government sites, online video site Hulu and gaming streaming site Twitch. Not only were the sites unavailable but visitors saw a range of error messages that often weren't much help explaining the problem. (Source: theguardian.com)

The outage is widely believed to be related to services from Fastly, a content delivery network that describes itself as an edge cloud platform.

Traffic Load Spread

In simple terms, Fastly frequently makes copies of its clients' sites and makes them available on servers around the world. That means visitors can access a copy on a server that's physically near them, meaning it loads quicker. (Source: bloomberg.com)

The setup also means Fastly can cope better if a site suddenly gets extremely popular. Rather than have a single server overloaded, it can spread the traffic across its network. That might mean a situation where every visitor connects a fraction of a second slower than normal rather than a situation where some people can't connect at all.

Single Point Of Failure

A content delivery network can also better cope with denial-of-service (DoS) attacks where criminals, protestors or trouble-makers flood a site with bogus traffic, often from hijacked computers, in the hope of making it unavailable.

The big problem is that the setup inherently means every connection from a visitor to a site has to go through Fastly. If, as appears to be the case, Fastly was out of action, that effectively acts as a complete blockage.

While an hour might not sound like long, it's a significant disruption to the businesses concerned. The effects may have been even more noticeable had the disruption not been mid-morning European time, meaning the US hadn't started business hours yet.

Although the most likely explanation in this case is a technical error, it does show why content delivery networks are an appealing target for cyber criminals, hostile governments and other groups looking to cause large scale disruption.

What's Your Opinion?

Is major sites being offline for an hour a big deal? Is it concerning that so many sites are reliant on a single business? Are the benefits of content delivery networks worth the risk of a very occasional outage?