A gateway is a node that allows you to gain entrance into a network and vice versa. On the Internet the node which is the stopping point can be a gateway or a host node. A computer that controls the traffic your network or your ISP (Internet Service Provider) receives is a node. In most homes a gateway is the device provided by the Internet Service Provider that connects users to the internet.
When a computer server serves as a Gateway node, the gateway node also operates as a firewall and a proxy server. A firewall is a system created to prevent unauthorized admission into a private network. A proxy server is located right between a client application such as a web browser and the real server. The proxy server sees if the client applications requests can be carried out by the real server.
Usually a gateway is associated with a router. A router is a device or sometimes computer software that lets you know the next network data should be sent to next. A router can be connected to two or more networks at a time, it decides the next destination of the data based on it's comprehension of the condition of the networks. A gateway is associated with a router because a router which uses headers and forwarding tables to figure out where packets or data is sent provides the path through which information is sent in and out a gateway.
So a gateway is one of the many ways we can communicate over the World Wide Web. The gateway allows us to enter different networks on the internet so we can transmit data back and forth. There's also software available where you can be able to run several networks on a computer. As you have come to see by now having a gateway on your computer has it's many benefits.