A router relays information between two different computer networks. The most common use of a router is relaying data to and from a personal computer and the Internet.
A router is able to both send and receive packets of information from computer networks. If a person is connected to the Internet via an ISP, or Internet service provider, the router obtains packets from the personal computer, before sending them to the Internet using the ISP's modem. The response, which is typically a Web page or other information from a queried address, returns to the router, which is then relayed back to the user's computer.