BGP

BGP (Border Gateway Protocol) is a standardized exterior gateway protocol designed to exchange routing information between different networks on the internet. It ensures that data packets find their way across the complex web of interconnected ISPs and enterprises to reach their destination. BGP is fundamental to the functioning of the global internet as it facilitates the determination of the most efficient routes for data transmission.

BGP was developed by the Internet Engineering Task Force (IETF) and first introduced in 1989, replacing the older Exterior Gateway Protocol (EGP). The protocol is defined chiefly by RFC 4271, among others. BGP operates by maintaining a table of IP networks or 'prefixes' that designate network reachability among autonomous systems (AS). By comparing these routes and their associated path attributes, BGP ensures that data packets take the most appropriate path across multiple ASes, improving efficiency and reliability. BGP's core functionality relies on its path vector mechanism, which records the entire route that data traverses. The protocol's ability to handle multiple pathways simultaneously and its policies for route selection make it robust and scalable, meeting the demands of today's extensive internet infrastructure.