Tag Archives: internet

What Browser?

Ok so you probably know eactly what a browser is and will have made an informed choice as to the one you are using right now (unless constrained by policies at work).
Ask your friends and family (you know – the ones who don’t need to ‘get a life’ as they do actually already have one!) this question though and you might be surprised at their answers!

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Technology Explained: How Does Wireless Internet Work?

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Technology Explained: How Does Wireless Internet Work?

radiotowerIn my role supporting SCADA units in the field, I’ve often been asked how does Wireless Internet work. I usually answer with the question, “Which kind of wireless Internet?” Some people say that WiFi is wireless Internet, some think of radio-based Internet access as wireless, some even think of satellite Internet access as wireless. Then there is cellular based Internet access as well. At that point, you guessed it, glazed over eyes and wandering away. Please don’t do that – I’ll get to the point soon.

Canopy 440 ReceiverReal wireless Internet access is most accurately described as the kind that is based on radio frequencies. You might see homes with the little white rectangular box mounted near their eaves trough. Those are folks with Wireless Internet Access.

Let’s work this from the Wireless Internet Service Provider (WISP) to your computer.

From your ISP there will either be cabling or a radio transmitter that will relay signals to a tower. It may go through several towers before it gets to your home, or you might be close enough that you catch it off the first one.

See, the challenge with wireless Internet service is that it should be line-of-sight. That means that if you were to put your head in the middle of the receiver and look straight ahead, you have to be able to see the tower. (I do NOT recommend doing this since those signals could be less-than-healthy for you.)


Once the signal makes it to your nearest tower, it then travels directly to your receiver.  From your receiver, it will go over ordinary networking cable (RJ-45) to your modulator/demodulator (you know it as a modem). When it is modulating, it is turning your outgoing information into something that the wireless network understands. When it is demodulating, it is turning the signal into something your computer will understand. Clear as mud? I thought so. Here’s a picture.

total_network

As I said before, this is all done with radio frequencies. Do you have a cordless telephone? It will probably have numbers on it that read something like 900 MHz, 2.4 GHz, 5.2 GHz or 5.7 GHz.? These are the radio frequencies in which your cordless phone operates. Well, so does wireless Internet!

The WISP’s use these frequencies because they don’t require a license to do so. Licenses cost money and come with severe restrictions, so why wouldn’t you use public frequencies? Ah hah! I heard someone say ’security’! You are correct. Yet communications over these frequencies are acceptably secure. That’s because encryption is added to the signal. They take something that someone might possible be able to unravel, put it through encryption and, voila, secure Internet signal. Well, as secure as it can be anyway. DES encryption is commonly used.

Now, I hear someone asking why there are different frequencies. Think of them like highways – too many cars on it and everything comes to a standstill. So we use more than one highway.

Something else to consider with wireless Internet is that the frequencies also offer different attributes. Have you noticed that you can’t take your new 5.2 GHz cordless phone three doors down and still be able to talk on it? Yet when you are in your house the clarity of voices on it beat your old 900Mhz phone easily.

It’s similar with wireless Internet. Looking at Motorola’s Canopy receivers, you’ll notice that the 900 Mhz receiver has an effective range of up to 40 miles! Then the 2.4GHz receiver is limited to about 5 miles. That’s a huge difference! Go all the way up to the 5.7 Ghz receiver and we’re down to a measly 2 miles. However, the 900 Mhz receiver is more likely to have its signal interfered with by other signals out there. So, your choice, range or quality of signal? Choose wisely.

Are you currently using stationary wireless a.k.a broadband wireless? Like it? Hate it? Does this article help you to understand better what is going on with it? Let us know, down below!

(By) Guy likes words and occasionally forms complete sentences. He can count to potato. Check out his USB shilling at USBDriven.com.Follow MakeUseOf on Twitter!

Yes It IS my mission to educate you all and these articles are a fairly painless way to do just that!

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Technology Explained: How Does a Router Work?

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Technology Explained: How Does a Router Work?

Oct. 10th, 2009 By Guy McDowell

routerLately, the Technology Explained articles have talked about the Internet and communications in general. This article will add to that series by explaining a very important piece of equipment – the router.

In order for a computer to connect to more than one other computer, you need a router or a hub. Two very different pieces of equipment that perform somewhat similar jobs. We’ll focus on the router since you very well may have one in your house.

Let me take a moment to explain to the more technically inclined that I understand that there are such things as token ring networks that don’t require a router or a hub. Yet, our average Internet user isn’t going to employ a token ring, so leave that alone, please.

Many of you will have wireless routers, a few of you may have wired routers. How the information gets to and from the router isn’t that important to this discussion. What is important is how does a router work – what happens inside the router with all that data coursing through it. To keep it simple, I’m going to use a 3 computer network to explain the routing principles.

So, let’s say you have three computers in your home and a connection to the Internet. This will give us a network that looks like such:

how does a router work

In the middle of that, is the wireless router. I know you knew that, but it had to be said. Wirelessly attached to it are a laptop, a PC, and a Mac (just for you Jackson!). Actually, the Mac is in there to show that the computers don’t necessarily need to be the same kind or platform. One might be sending up a file to work, one might be downloading something from YouTube and one is reading MakeUseOf.com – of course. All this information is coming down from, and up to, the Internet.

Believe it or not, the router can only talk to one of these things at a time! The process I’m about to talk about just happens so fast that it seems to happen all at once.

Let’s say that the Mac is uploading a file to work, the laptop is watching YouTube and the PC is surfing MakeUseOf.com.

Each communication happens in small packets of data. You might recall this from the How the Internet Works article I did awhile back. The IP address in that article was the important thing that allowed packets to find their way to your computer. Here’s a packet:

how does a router work

The important parts, for this article, are the Source Address and the Destination Address. These will be Internet Protocol (IP) addresses.

However, if you are using a router, your computer’s IP address is going to begin with either 198.168.0 or 10.0.0. This is because the powers-that-be decided that those IP address would be reserved for local network use. Like in a home network.

Here’s the catch. There are millions of local networks out there. So, at any point in time, there are millions of people using an IP address exactly like the one your computer is using on your home network. Your router will have to keep track of that AND tag the outgoing packets with the true IP address that your Internet Service Provider has given to your modem.  I’ll call that the external IP address. How does the router do that? That’s the question.

I am going to oversimplify this, not to speak down, but to keep this article a reasonable length. The router takes your computer’s local IP address out of the packet’s Source Address and puts it in a table. It then puts the external IP into the packets Source Address space. The router also copies the Destination Address IP from the packet and puts it in the table associated with your local IP. Confuzzled? Me too. I really had to think about how to say this in everyday speak and not geek-speak. Here’s a picture:

how does a router work

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how does a wireless router work

When the packet comes back from that server somewhere out on the Internet, the Destination Address IP is now your external IP and the Source Address IP is now the IP address of the server sending you a packet. (Note: that is the IP address of Telus.com – not my home IP address.)

Think of it like a letter. You send a friend a letter and the return address is yours, and the send-to address is theirs. They write a letter back and the return address is theirs and the send-to address is yours. See how that works? We should write more letters.

how does a wireless router work

Well, the router looks at the Source Address IP of the incoming packet and looks it up in the table as a former Destination Address IP. When it finds it, the router says, “Aha! Guy’s computer sent a packet to that IP address. His computer must be waiting for a reply! Here’s Guy’s local IP address so I’ll pull out the external IP address, pop his local IP address in and send it on its way!” That’ll do router, that’ll do.

how does a wireless router work

You can imagine, with how many thousands of packets travel in and out of your home every minute, how fast this sorting process has to be! It happens so fast, you never even notice the fact that at one moment the router is talking to the Mac, then the laptop, then maybe the Mac again, and then the PC. Miracles everywhere – just stop and notice.

I hope you enjoyed this article on how a router works, and now have a better appreciation of what’s going on in that silly box of electronics next to your modem. If there are any other technologies you’d like me, or our other great writers, to break down for you, I’d be glad to hear about it in the comments!

Image Credit: A.Mohsen Alhendi

(By) Guy likes words and occasionally forms complete sentences. He can count to potato. Check out his USB shilling at USBDriven.com.Follow MakeUseOf on Twitter!

All good useful stuff!

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