A network of networks
The internet is not one network. It is tens of thousands of independent networks — ISPs, content platforms, universities, enterprises — each run by its own team. Each is an Autonomous System with its own number.
The job of BGP
The Border Gateway Protocol lets these networks tell each other which IP address blocks (prefixes) they can deliver traffic to. When your ISP learns from a neighbour that it can reach a content network’s prefix, it can send your request that way.
Paths are lists of networks
Each BGP route carries an AS path — the sequence of networks the announcement has passed through. Routers prefer shorter paths by default, but that is only one factor.
Policy decides
Networks configure preferences based on business relationships. They generally prefer routes learned from customers (who pay them), then from peers (settlement-free), then from transit providers (whom they pay). That is why traffic sometimes takes a longer physical path than you might expect.
Why it matters to you
The paths chosen by BGP determine latency, cost and resilience. Exchange points like Peer1IX change the options available, creating short, direct paths between networks in the same city.
See it yourself
Type any IP or prefix into our BGP looking glass to see the AS paths that route collectors around the world observe.