Have you ever owned a suitcase or attache case combination lock? (click the picture on the left for a larger view)

How many different combinations are possible with that?

Well, if there are three wheels, you have 1,000 different combinations:

0-0-1, 0-0-2, 0-0-3, 0-0-4…and so on.
Continue reading ‘What your garage door opener has in common with Internet addressing’

Let’s do a thought experiment.

Imagine an automatic coffee-maker with its pot. Your job is to keep the coffee pot full.

Well, you certainly don’t want to have to get up all the time to check it. So you invent a device — a sensor — that can send you a signal when coffee is touching the sensor.

You put that sensor in the pot near the top. When the coffee reaches the same level as that sensor, the sensor sends you a signal that says “pot is full.” Cool!

But when the coffee level calls below that sensor, the sensor sends you a signal that means “pot empty.”

Not very accurate — sometimes you’ll wander over to make more coffee only to find as much as three-quarters of a pot (or more) left.

How can you improve this system?
Continue reading ‘More information is better’

In a previous post, I explained that networking involves the sharing of resources between two or more parties. But that is only possible if the two parties can find each other first.

In other words, before you can go to the movies, you have to know where the movie theater is. To make it easy, the movie theater has an address that describes its location in your town.

Computer networking is the same way. Before you can share a file or any other resource with another party, your computer must have an address that describes its location on the network.

There are many systems (or protocols) for computer addressing, but the most popular one is called Internet Protocol, or simply “IP.” That’s right, as in “TCP/IP.”

Here’s why you need to understand IP addressing:
Continue reading ‘What is your computer’s address?’