| Term | Description |
| Router | A router is the central switching device in a packet-switched network that directs and controls (routes) the flow of data. A traditional router routes packets within a single address realm, while a NAT router directs datagrams between different address realms. A NAT router sits on the border between two adress realms and performs such "transparent routing" by modifying addresses in IP headers, so that when packets enter another address realm they can be valid and routed properly. Routers are differentiated from data communications switches by the ability to perform higher-level functions necessary to the interconnection of different networks. Related: gateway |