You’ve probably been wondering about this for some time. How does the Internet work anyway? Well, its designers and engineers really don’t want you to have to worry about it. We say that the technology should be “transparent” to the user. Like when you go to start your car. It should just work!
But for you curious cats out there, let’s see if we can provide a basic overview to give you some understanding of the Internet’s inner workings. Let’s start with 0’s and 1’s. If you remember from your math classes in junior high (oh, I mean middle school – did I just date myself?), a binary form of counting consists of only two digits. But with those two digits you can count just as high as you can with the decimal system (0-9). Let’s count to ten in binary:
0000 — 0
0001 — 1
0010 — 2
0011 — 3
0100 — 4
0101 — 5
0110 — 6
0111 — 7
1000 — 8
1001 — 9
1010 — 10
Notice that in our decimal system, using 1 in the second place from the right signifies the number ten. But in binary, that same 10 is equal to the number two. Now what happens if we string eight places together in binary to form an octet. Each place is called a bit, and eight bits make a byte. Here is the number four in binary using eight places:
Now suppose we use a series of four octets. And let’s associate that binary number with its digital equivalent. Here is an example:
11000000.10101000.00011001.00000100 = 192.168.25.4
That, my friend, is called an IP address. Now we will assign that IP address (let’s not worry about how for the moment) to only one device in the network — your laptop, for instance! (If we assign it to two devices on the network, we will have something called an “IP address conflict”. You really don’t want one of those.) Once you decide which IP address you want to give to your laptop, you need to associate it with a Media Access Control address (MAC address). In doing so, you have associated your network address (IP address) with your physical address, or MAC address. Voilà, you have placed your laptop onto the network!
Figuring out binary equivalents might take a bit of effort. No problem. Rather than doing all the conversions on paper or in your head, why not let the computer do the work? You might want to play around with this IP Address to Binary Converter.
Now you may wonder how networks are divided. Let’s say you have 25 workstations to add to your network. Let’s cheat using this online subnet calculator. For the IP address, enter “192.168.25.1” (Just the number without the “”).
For the Subnet Mask, enter “255.255.255.224” (again, just the number without the “”). We only need enough IP addresses for 25 workstations (hosts). Now looking at the results, you will see that we have enough IP address for 30 workstations (hosts) in a range from 192.168.25.1 to 192.168.25.30. This is a range that you might use to put a group of people into their own separate networks – the accounting department, for example.
So now you may be wondering what your IP address is. Here’s how to find out in a Windows machine:
Click the Start button.
In the box, type in “cmd”. A black box should appear on the screen
.At the user prompt (are you feeling like a network engineer already?), type “ipconfig”.
Look for your IP address (you may need to scroll up). Find it? Great! (You may find more than one if your computer has multiple interfaces.)
What about the MAC address?
Let’s find it. Go back to your black box and type “ipconfig/all”. Look for something called “Physical Address”. You should see a number that looks like this:
##-##-##-##-##-## (It consists of numbers or letters.)
This is the physical address assigned to an interface your device by the manufacturer. What about the IP addresses and MAC addresses of other devices that you have encountered on your network? Try this: type “arp -a”. You should now see a whole list of addresses that represent interfaces on computers that have been stored in your computer’s Address Resolution Protocol (ARP) table. You computer has been busy talking to its computer buddies.
So now you have an introduction to how the Internet works with your computer. But there is so much more to learn. The Internet Protocol (IP) is on the network layer of what is called the OSI model. Networks consist of more than IP addresses.
One simple email address or tweet may cross a number of physical devices between you and the recipient of your message. For years network engineers have referred to that “transparent” technology between one point and another as a network “cloud”. (Today the term often refers to virtualization and centralized computing.)
Would you like to know more about networking? Are you wondering how network professionals troubleshoot? Want to know more about Internet protocols and technologies? Feel free to reply with any questions or comments. Let me know if you would like to know more.