The IP Protocol

The IP protocol allows sending data across an entire Internetwork. It handles routing of data (using routing tables), and packet fragmentation.

The IP protocol knows two device types: hosts, and routers. Hosts can send packets directly to devices on the same network. Routers can forward packets to machines on other networks.

The IP protocol is unreliable - IP packets may be discarded at any point in their transmition route, may arrive out of order, may arrive with corrupt content, may get lost, may arrive in duplicates, etc.