interdomainreititystä

Interdomain reititystä, commonly known as interdomain routing, is a fundamental concept in computer networking that deals with how data packets are forwarded across different autonomous systems (ASes). An autonomous system is a collection of IP networks and routers operated by one entity that has a single, clearly defined routing policy. Interdomain routing is distinct from intradomain routing, which manages routing within a single autonomous system.

The primary protocol used for interdomain routing is the Border Gateway Protocol (BGP). BGP is a path-vector routing protocol, meaning it exchanges reachability information in the form of paths. When a router in one AS needs to send a packet to a destination in another AS, it uses BGP to learn the best path through a series of interconnected ASes. This path information includes the sequence of AS numbers that the packet must traverse.

BGP allows ASes to exchange routing information and make decisions based on complex policies. These policies can consider factors such as link costs, performance, security, and business agreements between network providers. The goal of interdomain routing is to ensure that data packets can reach their intended destinations across the global internet, even though the internet is composed of many independent networks. The efficiency and effectiveness of interdomain routing are crucial for the overall functioning and scalability of the internet.