In telecommunications networking, a residential gateway allows the connection of a local area network (LAN) to a wide area network (WAN). The WAN can be a larger computer network (such as a municipal WAN that provides connectivity to the residences within the municipality), or the Internet. WAN connectivity may be provided through DSL, cable modem, a broadband mobile phone network, or other connections.
The term "residential gateway" was originally used to distinguish the inexpensive networking devices designated for use in the home from similar devices used in corporate LAN environments (which generally offered a greater array of capabilities). In recent years, however, the less expensive "residential gateways" have gained many of the capabilities of corporate gateways and the distinctions are fewer. Many home LANs now are able to provide most of the functions of small corporate LANs. Therefore the term "residential gateway" sometimes implies a less expensive, lower capability networking device.
The home gateway tends to have abundant interfaces, powerful functions and a more user-friendly interface. It is a manageable terminal with auto-configuration, and multi-service perceiving and bearing. The home gateway provides Quality of Service to simultaneously support different types of services. As a part of the carrier network, the home gateway supports remote control, detection and configuration.
Since the early 2000s the residential or home gateway has been used by Telecommunications Multiple Service Operators [MSOs] as a termination device for connecting consumer premises to a broadband delivery network.
One of the world’s first residential gateway devices was developed for Italian telecommunications service provider Fastweb in 2001 as part of the launch of the first commercial triple play service. Using its fiber network, Fastweb delivered voice, video and data services to a home gateway device – the first with embedded fiber termination – and enabled them to be distributed around the home via set-top boxes and routers.
Multiple devices have been described as "residential gateways":
- Cable modem
- DSL modem
- Wireless router
- Network switch
- Voice over internet protocol (VoIP) Analog telephony adapter
- Wireless access point
or any combination of the above.
A router usually provides:
- Internet protocol routing
- Network address translation (NAT)
- DHCP functions
- firewall functions
- LAN connectivity like a network switch
Most routers are self-contained components, using internally stored firmware. They are generally OS-independent (i.e. can be used with any operating system).
Wireless routers perform the same functions as a router, but also allow connectivity for wireless devices with the LAN, or between the wireless router and another wireless router. (The wireless router-wireless router connection can be within the LAN or can be between the LAN and a WAN.)
A modem (e.g. DSL modem, Cable modem) provides none of the functions of a router. It merely allows ATM or Ethernet or PPP traffic to be transmitted across telephone lines, cable wires, optical fibers, or wireless radio frequencies. 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 USB modem plugs into a single PC and allows a connection of that single PC to a WAN. If properly configured, the PC can also function as the router for a home LAN.
- An internal modem can be installed on a single PC (e.g. on a PCI card), also allowing that single PC to connect to a WAN. Again, the PC can be configured to function as a router for a home LAN.
A wireless access point can function in a similar fashion to a modem. It can allow a direct connection from a home LAN to a WAN, if a wireless router or access point is present on the WAN as well.
Beyond basic connectivity and routing, residential gateways can provide addition features, such as:
- Configuration via a web interface
- Dynamic DNS
See also 
- The Residential Gateway (a vision paper published in International Engineering Consortium’s 1996 Annual Review of Communications, p.457)
- IBM's Residential Gateway initiative (circa 1996)
- Home Gateway Initiative, a group of broadband providers proposing specifications for residential gateways
- The Residential Home Gateway on About.com
- Linux router HOWTO