Gateway in the computer network world is a piece of software or hardware device that translates between two dissimilar protocols. For example, VOIP gateway translates between IPnetwork and PSTN network for telephony communications. Unlike a proxy, a gateway receives messages as if it were the final receiver for the message. Due to possible mismatches between the inbound and outbound interfaces, a message may be modified and may have some or all of its meaning lost during the conversion process.
Gateway devices are commonly divided into the following three functional categories, or any combination of these three:
- Data Gateway - Data gateways are simple routers primarily used for data throughput. They provide pass-through support for network protocols and services and typically support both wired and wireless networking. Data gateways can be used to pool multiple Internet connections and secure private networks using a firewall. Some data gateways may also provide storage, such as e-mail and voice mail storage.
- Multimedia Gateway - In addition to data gateway features, multimedia gateways provide capabilities for audio and video content delivery. Multimedia gateways are often used in conjunction with digital entertainment devices and can provide centralized storage. Multimedia gateways also typically include encoding capabilities that transcode analog audio and video signals so users can enjoy media such as cable TV on a personal computer screen.
- Home Control Gateway - A home control gateway enables home control and security service management over a network. For example, users with a home control gateway can access automated lighting, heating, and security systems from work or while on vacation. Home control gateways also allow network service providers to offer new service packages and generate new revenue streams.