A residential gateway is a small consumer-grade gateway which bridges network access between connected local area network (LAN) hosts to a wide area network (WAN) (such as the Internet) via a modem, or directly connects to a WAN (as in EttH), while routing. The WAN is a larger computer network, generally operated by an Internet service provider.
A modem (e.g. DSL modem, cable modem) by itself provides none of the functions of a router. It merely allows ATM or PPP or PPPoE traffic to be transmitted across telephone lines, cable wires, optical fibers, wireless radio frequencies, or other physical layers. On the receiving end is another modem that re-converts the transmission format back into digital data packets. This allows network bridging using telephone, cable, optical, and radio connection methods. The modem also provides handshake protocols, so that the devices on each end of the connection are able to recognize each other. However, a modem generally provides few other network functions.
A cellular wireless access point can function in a similar fashion to a modem. It can allow a direct connection from a home LAN to a WWAN, if a wireless router or access point is present on the WAN as well and tethering is allowed.
Many modems now incorporate the features mentioned below and thus are appropriately described as residential gateways, such as some Internet providers which offer a cable modem router combo.
It may also provide other functions such as Dynamic DNS, and converged triple play services such as TV and telephony.
Most gateways are self-contained components, using internally stored firmware. They are generally platform-independent, i.e., they can serve any operating system.
perform the same functions as a wired router and base station, but allow connectivity for wireless devices with the LAN, or as a Network bridge between the wireless router and another wireless router for a mesh networking (the wireless router-wireless router connection can be within the LAN or can be between the LAN and WWAN).
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