[shahsyed]

Understood.

I had question: This is what we can only perceive through internet/routing table entries right?

Internal to FB, we don't know what had caused issues that led to the BGP UPDATE.

That's kind of what has been confusing me - there's a lot of speculation around FB's data center design and what actually happened, but we actually don't know for sure until they post an RCA - please correct me if I'm wrong here.

[jcims]

You are on the right path. It's entirely possible the BGP routing updates that we witnessed 'out here' on the Internet were simply a side effect of the actual network problem that impacted the company. As toast0 mentioned above it is less likely to be DNS-related just because most of the related services don't tend to build dependencies on DNS (in part for this reason).