The router, like it’s name implies, directs, or routes, data between networks and is one of the key components to any network, big or small. While it is not technically required for a network to function, it is needed to communicate outside of a given network.
A Very Brief History
The origin of the router dates back to the mid 1960s where the concept was first used by Welsh computer scientist, Donald Davies.1The ARPANET & Computer Networks Over the years it has gone by different names and has been combined with other devices; however, the basic functions remain the same.
The Default Gateway
Before we get too deep into routers, we need to know what a default gateway is. When a new client joins a network, it is given a few things from DHCP: an IP Address, default gateway, and some other settings. The default gateway is where clients send all data when a path is not known. Every client should have one default gateway set that points to the main router connected to the internet.
How It Works
In the diagram above, the router links two different networks together, Network A and Network B. Both clients, PC0 and PC1, have no idea how to reach the other or about the other’s existence. However, with the use of the router, data can be sent between them.
PC0 wants to send data to PC1, but does not know how to get to it. PC0 will send the message to its default gateway for the router to handle. The router knows about PC1 and can forward the message even though the two computers are on different networks. Remember, this is only possible because the router connects to both networks and can interact with both networks.
The functionality and concept is the same when interacting with the internet. Data is sent from a device to the router, which is then routed to the proper website online. While the device may not know how to get to the website, the router sends the data onto the internet for delivery. Data moving across the internet will generally go through multiple routers before reaching the final destination.
Ralph Breaks the Internet does a great job visualizing the internet and how it is all interconnected. Each of the large buildings are a visualization of a web server and the content within it. To access the data a user must use a door, or in our world a router.
A router at a fortune 500 company performs the same actions as your at home, but not all are created equal. Business grade routers are designed for high volume and fast response times. While a business router typically only performs one function, routing data, many home routers have multiple functions in the same unit. These other functions include wireless access points, modems, and switching capabilities. These devices are called multifunctional routers, but they still perform the basic router functions. We will take a look at these other devices in the future.