[divbzero]

Besides BGP, are there other somewhat-obscure Internet protocols that have the power to cause major outages?

[mitchs]

BGP is spoken between networks. There are a lesser known "IGP" protocols stitching together the insides of those networks. IS-IS and OSPF being the most notable. Though the nature of the beast is that when you screw up BGP everyone sees it, and when you screw up your IGP it could just look like servers or load balancers having a bad day. Though if a telco messes them up everyone notices.

[midasuni]

DNS

[grishka]

DNS isn't obscure, most people who've ever used the internet have seen that acronym.

[midasuni]

Neither is BGP

[grishka]

BGP isn't used by end-user devices, so consequently no one outside of those who researched how the internet works knows about it.