Router - How it works
If you've been brought up in the 21st century then you probably take a lot of
things for granted that 30 years ago people just didn't have. One of those
things is the Internet and its ability to be able to connect people from all
over the world and allow them to interact with each other in a variety of ways
including sending email, visiting web sites, joining forums, attending online
chats and countless other things. But none of this would be possible if it
weren't for a device that most people have never seen and probably don't even
know exist, called a router.
Routers are pieces of equipment that send messages from everyone connected to
the network along thousands of different pathways. We're going to take a behind
the scenes look at exactly how these routers work.
Let's say you're sending an email to a friend of yours who is living across
country or even in another part of the world. How does the email know to end up
on your friend's computer instead of all the other millions of computers all
over the world? A good part of the work to get these messages from one computer
to another is handled by routers. Rather than pass messages within networks,
routers pass messages from one network to another.
To get an idea of how this works, let's take a very simple example.
Let's say you have two departments. Department A with 5 employees and
Department B with 5 employees. Let's say that Employee 1 from Department A wants
to send an email to Employee 3 at Department B. Each department is part of its
own network of computers. A router links the two networks together so that they
can communicate with each other. It is the only piece of equipment that sees
both networks. Many people ask, why not just make one network? The simple answer
is that if the two departments do two completely different jobs for the company
and send massive amounts of info within the department, you don't want to slow
down the other department with the one department's info. To ease what they call
the "traffic burden" the two departments are separated into two networks with a
router put between them to connect them just in case they do want to communicate
for some reason.
The way the router knows what to send where is with what is called a
configuration table. These configuration table consists of info on which
connections lead to which addresses, priorities for each connection, and rules
for how to handle the passing of info between networks. The router then has two
basic jobs. The main task is to make sure that information doesn't go where it's
not needed so that the volume of data doesn't clog up the network and the next
task is to make sure the information goes to where it's supposed to go.
To simplify how this happens, the router looks at the destination address of
each packet sent from the source location. It checks its table to see where this
address is and sends each packet to that address, bypassing all the other
addresses in the network so as not to slow the network down.
By Michael Russell