Slightly off topic, but if I want to understand the concepts discussed in this article, what all topics should I learn? Is this a good starting place or enough to understand everything in this article - https://beej.us/guide/bgnet/
Kind of like wanting to learn how a car engine works and asking about fleet management in trucks/ lorries.
BGP is one of things I've learnt then forget the next day (multiple times)
The goal for me is conceptual understanding, not to build an ISP. And network knowledge is light... just enough to be a cloud monkey
BGP is just the way networks exchange routes (paths to a specific IP address) between each other. Once you know a little bit about how routing works it will make sense.
http://freedman.net/bgp102.ppt
http://avi.freedman.net/fromnetaxs/multi.html