Facebook and its associated apps WhatsApp, Instagram and others were inaccessible Monday, October 4, 2021 for nearly six hours affecting billions of users. Facebook attributed it to a bad configuration change made to its backbone routers. Several other researchers attributed the downtime to a Border Gateway Protocol or BGP.

As we know, internet is a network of networks. BGP plays a role in routing information from the massive networks to the rest of the internet. Basically, it is the way to exchange routing information in these systems. BGP acts as a postal service of the internet. It does data routing on the internet.

In the present breakdown, Facebook could not announce the routes, leading to their servers going offline. Facebook thus broke off the internet.