What is BGP (Border Gateway Protocol)?
How does BGP Work?
Internet traffic is directed by routers, and those routers have massive, continuously updated lists of potential routes by which to deliver network packets from origin to destination. They are like Waze for the internet: if one route is too backed up, they choose a different one. But how does a router know which routes and networks are available?
BGP manages routing and communications between networks that have an assigned ASN. Networks that have an assigned ASN are groups of smaller networks containing hundreds or thousands of routers. BGP allows traffic originating from a router assigned to a given ASN to find the most efficient path for traffic to take in order to reach a given destination. This includes routing traffic within a network that has a specific ASN as well between networks that have different ASN designations.
BGP facilitates this communication by keeping a list of all available pathways between ASN identified networks, IE knowing all possible paths that traffic can take, then taking into account traffic conditions in much the same way a driver will route around a backed-up highway using side streets.