The gateway allows networks to be interconnected through different protocols and architectures at all communication levels, and these devices are often referred to as a computer.
What Does a Gateway Do?
The main purpose of gateways is to convert the information from the protocol used in a network to the protocol used in the target network.
Gateways do not work as a Bridge and are not simply a bridge that conveys information without conversion between two systems. These devices modify and transmit the packet or syntax of information to match the target system. Also, they work at the Application layer of the OSI model.
While there are many ways to connect computer networks, they can be difficult. For example, different networks with TCP/IP and SNA architecture can also be interconnected.
Gateways do not provide routing functions in the network, but only transmit packets so that data traffic can be read.
When a GW receives a packet from a network, it translates the packet from the format used on the network to a common format among gateways. It then sends the packet to another GW, the target device receives this packet and translates it into the format used on its network.
How Does It Work?
The gateway normally routes computers belonging to a local area network connected to it to gain access to an external network and often performs IP address conversion.
This address translation function enables computers on the local area network to access the Internet, usually by sharing a single Internet connection and a single IP address externally.
In-home environments, ADSL or cable modem routers are used as gateways to connect the home’s local network to the Internet, but they cannot connect two separate networks with different protocols, they can only connect two independent networks using NAT.
The address of a GW is usually determined by the IP block in your Internet modem’s LAN settings. For example, if your modem’s IP block is 192.168.1.0/24, the GW address of clients on the network will be the modem’s IP address, since the modem’s IP address will most likely be 192.168.1.1.
Or if a server computer is configured as a GW, it will necessarily need at least two network adapters, since one network adapter will be configured for the local network and the other for the target network.
In this case, the default gateway server will be the default route assigned to the local network, and its function is to send the packet over the default route by sending any packets that it does not know through which interface the incoming packets will send or that cannot be defined in network device routes.
There are two types of gateways: network adapters or software or external hardware.
Network Adapter or Software Based System
These devices are defined as computers equipped with network adapters of different protocols that correspond to segments of different network types to be interconnected.
This type allows different software protocols usually assigned to computers to translate data traffic.
External Hardware-Based System
Hardware-based GW devices not only translate protocols but are specialized smart devices that allow communication between devices with different architectures and even in different operating system environments.