Gateway (telecommunications)

A gateway [ geɪtweɪ ] (English for exit and entrance, literally gateway ) connects computer networks which may be based on completely different network protocols. As an example, a gateway e-mail in text or convert vice versa. The protocols for e-mail and SMS are incompatible with each other, but by means of e- mail -to- SMS gateway data can be transferred from one type of network to another. Another example would be e- mail to fax.

For historical reasons, the term gateway is used nowadays for some services even though no conversion between protocols takes place more. An example of this is the default gateway.

Operation

To this end, takes a Gateway from a protocol conversion. The Gateway everything is allowed that is necessary to convert the data, including the omission of information if it can not be transported in the target network. In detail, all the log information that is appended to a data packet (for example, IPX / SPX), removed and replaced with other ( for example, the Internet protocol suite ). There is also the gateway for many other uses, such as SMS gateways (email to Short Message Service), fax to email, email to language.

Demarcation to the default gateway as the router (default gateway)

In the early days of IP it was not uncommon forced to connect networks of different types with each other and thus inevitably to convert their protocols. Because IP was confronted with protocols such as DECnet, SNA and Novell's IPX / SPX. The term default gateway is the IP network configuration should make clear the administrator that he can enter a gateway here. But what is there actually used depends on the particular network architecture.

With the dominance of the IP protocol, the router attracted more and more often to the point of the gateway. There are now in this segment barely gateways, because the networks communicate almost exclusively via the IP protocol. A protocol conversion is no longer required.

Instead of converting protocols, only all not belonging to a subnet network requests heads the default gateway an IP configuration so today in a different subnet on and fulfilled simply the functions of a router, which is why the term "default router " would nowadays more appropriate. Gateways are therefore in common parlance often equated with routers, although routers are no gateways.

Routers operate at the third layer ( network layer ) of the OSI reference model, a gateway, however, can be implemented in four to seven layers.

Internet gateway

In some cases a device consisting of a DSL router and DSL modem is referred to as an Internet gateway in the home. These devices combine, in simple terms, the function of interconnect networks (routing), with the ability to use different protocols for this ( gateway). For IP packets are usually sent from the home network with broadband use over the PPPoE protocol in the network of the provider.

The protocol designation of a default gateway is to call at the implementation level as multilayered, because in contrast to the simple router is the ability of an independent, temporarily of a main system independent design and commissioning. This refers not only to WAN activities, but also to all processes which are possible today on operating systems.

On the other hand, may be another name for making a VPN connection through a secure tunnel the Internet gateway.

VPN Gateway

A VPN gateway enables over a public network such as the Internet, for example, secure access to a remote corporate network, which is normally not open to the public. Thus, various services, such as email, intranet or network shares, which actually only LAN internally available to be used on a tunneled connection.

Other gateways

The gateway as network service providers should not be confused with the "Service Gateway " concept, as represented for example by OSGi - even if there are certainly overlaps.

In the telecommunications gateway is also referred to as a gateway. Softswitch or media gateway in this case serve as an interface between different types of networks, which take over the the different media (language ) digital transcoding. A gateway may be used for example between a circuit-switched network (ISDN) and an IP-based packet-oriented network (NGN).

In the automotive technology, gateways often between different data buses such as CAN in different speed versions, the MOST bus, etc. A typical configuration in an automobile consists of a "fast" CAN bus for motor control and similar real-time control units and a "slow " CAN bus for control units with few and rarely occurring data ( " comfort bus " for tire pressure monitoring system or tank sensor ). For certain purposes ( diagnosis), some data must also be placed on each other's bus. The gateway copied for this purpose, the data from one bus to the other. This gateway can act as its own control unit or part of an existing, larger control device (for example, the instrument cluster ), which must operate connections to all bus versions.

• Network device
• Gateway ( Network Engineering)