Explained | What is CDN and how is it linked to the massive internet outage?

The major websites were inaccessible due to an issue with the content delivery network (CDN) of Fastly, an American cloud computing service provider.   | Photo Credit: Reuters

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On Tuesday, a number of websites including Amazon, Reddit, BBC, New York times, Guardian, Financial Times, and Reddit became unavailable. All users could see was a ‘503 error’, meaning the browser was not able to access the server.

These major websites were inaccessible due to an issue with the content delivery network (CDN) of Fastly, an American cloud computing service provider. Fastly said it was investigating the impact of its CDN services and an hour later, it applied a fix. But what is CDN and why is it important for functioning of the Internet?

Dr. Corinne Cath-Speth, a P.H.D from The Oxford Internet Institute explained on Twitter the role of the content delivery network and cloud service providers like Fastly.

The internet was built as a peer-to-peer network that enables each user to request and access content on a peer’s computer, which acts as a server hosting that particular content.

However, the requested content on the hosting server can be far away and will take longer to load. The size of the world and the physical limits of the cables and wires restricts connectivity.

What is a CDN?

People connect to websites and applications from different parts of the world to access content. If a website’s servers are based in New York city for example, people farther from it will experience slower content delivery than those within the city. This creates inconsistency in user experience. Content Delivery Network, or CDN, solves this problem of delayed content.

CDN delivers content from the website to users in different geographies in a quick, reliable, secure and efficient way. It is made up of a distributed group of servers in different locations. This allows major websites to keep a copy of their website closer to the customers.

The CDN server closest to a user is termed as an edge server. Whenever a user requests content, they are connected to the closest edge server for fast delivery and improved user experience. Many platforms today keep their geographically relevant data closer to where it is consumed for this very reason.

Today, a large web traffic passes through CDNs. CDNs also help protect companies against traffic spikes and malicious attack such as Distributed Denial of Service (DDOS) attacks.

However, when a major CDN provider such as Fastly fails, multiple websites are affected. As requests to CDN hosted content were not serviceable, major websites went down.

Avinash Prasad, Vice President and Head for Managed Security Services and Content Delivery Network, Tata Communications said there has been a shift from conventional viewing to internet-based. People are increasingly moving from text to video and from recorded to live and interactive viewing and it has put pressure on network infrastructures of service providers, media houses and online businesses, he added.

This is not the first instance of CDNs causing many websites to go down. In 2020, issues with another CDN provider, Cloudflare, hit Discord, Shopify and few companies. These outages are an example for centralisation of internet in the hands of few.

Dr.Corinne reckons that this market is relatively small and each company serves a large number of clients.

"This means that a technical hiccup in a single company can have huge ramifications," she said. "This in turn--raises major questions about the dangers of (power) consolidation in the cloud market & the unquestioned influence these often invisible actors have over access to information."

Prasad suggested having real-time monitoring capability in-built within CDN eco-system, that predicts and prepares for any service issues enabling proactive resolution. This coupled with an integrated security capability helps detect malicious attacks early.

"This blended approach of leveraging software development and deployment, capacity management and scaling, and cyber resilience will help prepare both, the service providers and the media houses, for better levels of fault handling,” Prasad said.

(Update: Added quotes from Tata Communications)

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Printable version | Jun 22, 2021 10:39:23 PM |

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