Internet Connection Sharing

Why buy Wi-Fi? I answered that question in the first paragraph of this chapter: The #1 reason people put wireless networks in place is to share an Internet connection among family members without knocking holes in the walls and pulling wires. In older times, families sometimes shared a single Internet dialup account, but it often required a second phone line, and only one family member could be logged in at once. This led to a lot of yelling down the halls of things like 'Mike, dammit, are you still on that thing??!?' and fistfights among siblings.

Sharing Internet connections can be done with wires, of course. Creating a wired network using a cheap broadband router appliance like the famous Linksys BEFSR41 'blue box' has for years allowed several people to use the same Internet connection at the same time. The Internet connection cable was plugged into the back of the router, and all the computers wishing to share the connection were plugged into the router as well, all with cables.

Sharing an Internet connection seamlessly is possible because the Internet is a packetbased network. Files or data streams like text from a Web site are broken up into little chunks called packets, which are then routed individually to wherever they have to go. The router splits an Internet connection by looking at the packets entering the house single-file on the Internet connection, deciphering the addresses attached to all the packets, and then routing those packets individually to whichever computer in the house the packets are addressed to. The router works like a post office sorting mail: The mail comes into the post office on the back of a truck in one huge unsorted sack, and then the postal workers sort the pile into smaller piles, each of which is then delivered to a separate home or office.

If everybody in the house is bringing down MP3 music files or other large data files at the same time, the connection may seem to slow down. Still, because all the data is bundled into individually addressed packets, nothing in the data stream interferes with anything else, and each person in the house has the impression that he or she is the only one using the Internet connection.

This worked (and still works) beautifully. However, in those older times every computer in the house had to be connected to the router via a relatively fat wire called a 'category 5' cable, 'CAT5' for short. Wi-Fi put an end to the running of wires. More recently, the router and access point have been combined into a single appliance called a wireless residential gateway. This saves some space, some cable, and some complexity, and works just as well.

The router or gateway knows another trick that can be very useful: It limits how much the outside world can learn about the house's network. Some Internet Service Providers (ISPs) object to people sharing a single Internet connection among several computers, but the router makes it almost impossible for an ISP to determine how many computers are connected to the network. The router makes the network look like only one computer from the outside, no matter how many computers are in fact connected to the router. Most ISPs now cease to make a fuss over this, but some still do. Read the fine print of your ISP service agreement to see what the details are. There seems to be a general policy of 'don't ask, don't tell' about this issue, and if you have trouble getting your home network to work, it's probably best not to ask your ISP for help. Their job is to get Internet packets into your home. What you do with the packets once they arrive is your challenge-and helping you with that challenge is what this book is about.



Jeff Duntemann's Drive-By Wi-Fi Guide
Jeff Duntemanns Drive-By Wi-Fi Guide
ISBN: 1932111743
EAN: 2147483647
Year: 2005
Pages: 181

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