How are IP addresses structured to enable efficient routing?

Routing is a critical core internet function. It has to be fast. Really fast. If all IP address required their own routes that each router would have to store, routing tables would have around 4 billion entries. Routers use special hardware to improve routing performance and those hardware components cannot hold anywhere close to 4 billion entries. Instead, to reduce the number of routing table entries we organize IP address hierarchically. This allows routers to make routing decisions by only examining some part of the prefix of the IP address, rather than the entire address.
Credits: Talking: Geoffrey Challen (Assistant Professor, Computer Science and Engineering, University at Buffalo). Producing: Greg Bunyea (Undergraduate, Computer Science and Engineering, University at Buffalo).
Part of the www.internet-c... online internet course. A blue Systems Research Group (blue.cse.buffa...) production.