The two major components in a small computer network are a modem (cable or DSL) and a wireless router. The router is wired to the modem, and the modem is wired to the cable company's coaxial cable or the telephone company's DSL phone line. For Internet access via satellite, the router is wired to a satellite modem.
Modem - Establish and Convert
The modem establishes and maintains the connection with the Internet provider's service and converts the signals from and to the router appropriately.
Router - Route and Keep Track
The router forwards traffic destined for the Internet to the modem, while keeping internal traffic (computer to computer, computer to printer, etc.) from leaving the network. Using assigned numbers, the router keeps track of which computer made a request to the Internet in order to send responses back to that computer only. For details on the assignment process, see TCP/IP port
A wireless router is commonly used in the home and small business, which adds other functions. For more details, see wireless router
and wireless LAN