What’s a Router and What Does it Do?

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The router is the black box that sits quietly, but not necessarily invisibly, in your home unobtrusively giving you access to the Internet.

Some of you won’t care how it does this, so long as it continues to sit there with its blinking lights serving up your entertainment, but for the rest of you who’d like an insight into what this bit of kit does and how it does it then read on.

A router is in fact absolutely essential: it makes sure that the right data from the Internet gets passed to the right device; it knows the best routes to send your data on; and, it is the connection between the millions of networks on the Internet. Think of it like the mail service; picking up your letter, reading the address, and then deciding the quickest way to get it to its destination.

So How Does this All Work?

Envelopes, boxes, and packets

When you make a request for data from a website – or fill in a form and send data – that information is wrapped up in many self-contained envelopes called “packets”. These packets not only contain the data but also include the name and address of the recipient as well as a label telling them which order to reassemble the packets in – this is because the data is often too large to fit into a single packet.

Addressing packets

Online there aren’t any street names; everything on the Internet has an IP address. Web sites may have names we understand in our languages, but behind that there is an IP address working in the background to make sure the computer networks know how to read it. When the packet is created the label also gets a return address and that is your IP address. If you have a static IP address, when you sign up with an ISP it will assign your network an IP address. In most cases, when the IP address is dynamic, it is allocated to when your modem/router links up to the ISP network.

Making sure all your home devices have an address

Home routers have an extra job: rather than just route data between networks in the best possible way, they also have to create a local network for your devices. They need to do this because when you get an IP address from your ISP, that IP address is for your network, not for every device on your network. You no doubt have phones, tablets, notebooks, and gaming devices all connected to your router requesting different information at the same time. Your router has to be able to distinguish between your different devices by assigning a local network address to each device.

The next issue for your router is that the Internet is only going to understand your network IP address, not your local one; this means that it must readdress the packets it receives from your devices with your network IP address and then remember to put the correct device address back on when it receives it the packet back.

Sending your request in the right direction

Now the packet is ready to hit the Internet Superhighway.  The reason for this name is because it’s like a gigantic road system with a complicated network of highways, byways, lanes and footpaths, taking data from one device to another in the blink of an eye. However, the next issue is that while a packet has an address it doesn’t actually have a map of how to get there. This is where routers come in again.

Routers take the data, read the address and then, using a map or “routing table”, shoot it off in the right direction using the fastest route possible to the next router, which in turn sends it to the next nearest router and so on until it reaches its destination.

Some analogies

Think of those quest movies where they have to get to a mythical land and the only thing they have to go on is the name of the person who might have been there. Invariably, that person knows another person and eventually they get to their destination. The router is that person bouncing you around. Of course, routers can do this at light speed and they don’t make you answer cryptic questions to know where the next router is. They are also able to dynamically learn the best routes for your data requests so next time a packet sets out from one of your devices it knows exactly where to go.

Another example

You can also think of the router as similar to the sorting, collecting and delivering of a letter. If you want to send a letter to another country, it will go from your mailbox to a local sorting office, state, national, international and then back to a local office in the other country. At each stage someone is making a decision about the best way to get from A to B. Your local mail sorting office won’t know where a particular address is in another country and they can’t deliver it there themselves, but know how to pass it along. This is what a router does, learning all the time.

Checking an information superhighway journey

If you want to see the journey from your computer to a how many hops it is between the computer you’re reading this on and the securifi.com website type the following into a Windows command prompt: tracert www.securifi.com, on a Mac go to the Network Utility and click Traceroute and enter www.securifi.com.

Conclusion

So there you have it. Your humble router is extremely important because, without it, you would not be able to have more than one device using your Internet connection and your favorite TV show would be wandering around in cyberspace lost.

Now a router can either be wired or wireless. The difference being that you are connecting devices to it either over WiFi or through an Ethernet cable: WiFi offers greater flexibility of movement around your home while wired can offer greater speeds. Almost all routers now have both WiFi and Ethernet functionality – with WiFi being the primary way people connect to the net and get their daily fix.

But all routers aren’t created equal: there are a number of different standards for WiFi and these affect your WiFi signal strength, and there are also lots of features that you can use to enhance and maximize your signal strength – as well as improve privacy. We will cover that in another the next article.

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