The internet is a global system of interconnected computer networks that connect billions of devices worldwide using the TCP/IP protocol. It consists of private, public, academic, business and government networks linked together using various networking technologies. The internet facilitates the sharing of a vast range of information resources and services, including the World Wide Web, email, and file sharing between users in over 100 connected countries, representing billions of people worldwide. IP addresses and domain names are different but connected identifiers that allow devices and networks to be located online. Data is broken into packets which are transmitted individually and reassembled at their destination to reform the original data, allowing for message routing flexibility. Routers determine the pathways for sending information between computers over the internet.