BGP, or Border Gateway Protocol, is a protocol that allows different networks to communicate and exchange routing information. BGP works by exchanging information called BGP updates between routers, which contain information about network prefixes and the path to reach them. This information is used to construct a routing table, which determines the best path for traffic to flow between different networks.
BGP operates on a system of autonomous systems (AS), or networks that are under a single administrative control. Each AS advertises its network prefixes to its neighboring ASes using BGP updates, and these updates are propagated throughout the internet until all networks have the necessary routing information to reach each other.
BGP is a complex protocol that uses multiple mechanisms to ensure stable and efficient routing. These mechanisms include route aggregation, which reduces the number of routes that need to be advertised, and route filtering, which allows networks to selectively advertise or block certain routes. BGP also includes mechanisms for detecting and resolving routing loops, maintaining path diversity, and balancing traffic across multiple paths.
Overall, BGP plays a critical role in ensuring the smooth operation of the internet, allowing networks to interconnect and exchange traffic in a flexible and efficient manner.
