Week 1 MIST 7500 - What is a router?

If you have ever sent an email, viewed a webpage, or bought anything online (which unless you've been living under a rock for the past decade, you most certainly have) then you have used a router.  Most people, however, wouldn't even know that or probably care for that matter because it's all happening behind the scenes.  The internet is an enormous network or networks that allows intercommunication and without routers none of it would be possible.

So what is a router actually?  What does it do?  To put it in simple terms, think of a big intersection in a major city.  You've got cars coming in all sorts of directions, with different types of people going to many different places.  In the middle of all of this is a traffic light that decides who goes and who stops.  It's very similar to how a router works, it "routes" the traffic on the internet making sure you can send and receive those emails and buy that great deal you found on eBay.

Here is an image of a industrial sized router that handles enormous traffic loads:

And here is a picture of a home router:

So let's discuss more specifically what a router does, as it pertains to doing things on the internet.


MAC Address - every device on the internet needs an address to identify itself as unique to other devices.  When you send a piece of mail there is a Sent From and Send To address and both have to be unique so you know exactly where your mail is going and who it came from.  Much is the same with the internet and routers.  The router knows when your device is trying to access information because it recognizes your unique address.  Think of this example, imagine you and someone else are both accessing your internet connection in your home at the same time.  Both computers are going through a router after you connect and access websites or send/receive email.  The router will know which computer is trying to access what based on the MAC address.  So you get to pull up your website, and your family member gets to send/receive emails.



Packets - everything that you do on the internet is handled through packets.  When you send an email, for instance, the entire email is broken up into several different packets that contain information like who sent it, where it is going, and of course the actual contents (your message) in the email.  The router handles all of these packets by routing and distributing what needs to go where.  There are packets that make their destination, packets that fail and are deleted, and packets that are sent in redundancy.  The router handles all of these very concisely and very quickly, there are several steps that occur when a packet is first sent to when the packet is finally received and the router handles most all of this in the blink of an eye.

Routing Table - the routing table is basically a collection of information that allows all this packet switching to occur without errors.  There are a set of instructions or "protocols" that determine how each packet is handled and any exceptions.  It could just be a series of a half dozen lines or thousands depending on the complexity of the data or the network the data is on.


All of these technologies together allow you to access content on the internet within a matter of seconds.  All of this information travels through the router within a matter of seconds.  The router is really the backbone of how the internet works, it is said that without routers there would be no internet.


We could talk about this topic in much more detail and fill up several pages, but hopefully this post provides you with a basic understanding of what a router is and how it works.  Maybe after reading this you will appreciate the fact that routers exist to get us that much needed facebook update or email that we just can't seem to live without.