Network Part 4 - Where to Split, Why to Read?

Published: April 29, 2026 October 4, 2021. Facebook, Instagram, and WhatsApp went completely dark for roughly six hours — all at once. The servers were fine. No bad deploy. A single command run during routine maintenance withdrew every one of Facebook's BGP routes. The internet forgot how to reach Facebook's data centers. Traffic had nowhere to go. Facebook ceased to exist on the internet. The servers were running. The load balancers were healthy. Everything was fine. Requests just couldn't get