The morning of this Tuesday (8) started with thousands of websites down, including those of major media groups, streaming services, companies from different sectors and the British government network. What appeared to be a hacker megaoffensive was the result of a technical problem with a CDN (content delivery network) in the cloud.
Websites from companies such as The New York Times, BBC, Financial Times, Spotify, Twitch, Hulu, HBO Max and Reddit used the same global CDN, from the San Francisco company Fastly, which reported an incident on one of its services at 9:58, on Greenwich Mean Time (6:58 GMT). The problem was identified and fixed an hour later, according to the company’s website.
While not a popular term among internet users, CDN is an essential piece of infrastructure. And it allows the simultaneous consumption of heavy files, such as movies and music among thousands of people.
Technically, it is a server that stores mini-copies of these files and has the function of quickly delivering content to the final consumer and oxygenating the providers’ networks.
A company may have multiple decentralized CDNs to supply its customers in different regions. This way, the internet user does not need to “search” the content in the data center of origin.
This technology has become popular as internet consumption has shifted from text and photo to video and voice—heavier and more time-consuming to reach multiple destinations at once. To improve the user experience, the industry started to distribute small copies of its content, which are stored on these servers.
CDNs are so common for internet traffic that a technical problem on a single machine can crash thousands of pages. In recent years, with the increased use of streaming, CDN operators have evolved their intelligence to meet the demand for certain content: a server in Brazil will not have the entire Netflix catalog, for example, but the videos most consumed by subscribers. Latin America in Brazilian Portuguese.
In fact, it was the Portuguese from Brazil who protected the country from this morning’s crash. As the national language is different from that of other regions, such as Cape Verde and Portugal, most of the content is hosted on CDNs in the country itself.
“Imagine if all Google content was in San José [cidade onde fica a sede da empresa, na Califórnia]. Everyone would have to ‘leave the house, get the content and come back’, going through undersea and terrestrial fiber, congesting traffic, Google would need an unimaginable amount of bandwidth. It only manages to deliver because it has broken down into zillions of CDNs around the planet,” says Professor Lacier Dias, a partner at the Solintel company.
According to him, there are hundreds of CDNs in Brazil, but telecommunications companies cannot say who owns them because the structure is considered sensitive. “An Apple CDN, for example, contains copies of the company’s applications.”
Who receives the CDN is the internet operator, such as Vivo or Claro. Companies can have their own structures, such as Google, Facebook and Netflix, or hire specialized ones, such as Fastly.
The content of a few services and some CDNs account for a large portion of an internet provider’s data traffic. It is estimated that Google, Youtube, Netflix and Facebook together account for 40% to 60% of a provider’s bandwidth, according to the Internet Steering Committee.