Wireless Networks
Copyright Nash Networks 2007
Wireless networks work by transmitting data as radio waves - much like mobile phone, TV and radio signals. The radio waves are transmitted through a wireless router to another device, e.g. computer, printer or cable Internet connection.
Requirements For A Wireless Network
Wireless networks are relatively easy and inexpensive to set up, and most routers' Web interfaces are virtually self-explanatory.
Most new laptops and some new desktop computers have built-in wireless adapters. Other computers need to have a wireless adapter installed. You also need a wireless router, to link the wireless computer(s) to the network and/or cable Internet connection.
Wi-Fi Hotspots
Wireless hotspots are wireless networks in public places. Typically, they are found in cafes, hotels and other public spaces. They can be open, meaning they can be freely accessed by anyone with a wireless-enabled computer, or restricted, which usually means you have to pay to use the service.
If you switch on a Wi-Fi-enabled computer inside a hotspot, it will pop up a message telling you that you are inside a network, and ask if you want to connect to it. At that point, or when you try connect to the Internet, you might be asked for a password or payment.
Toronto Hydro Telecom recently announced plans to roll out a huge Wi-Fi hotspot covering the entire downtown core. This is due to be completed on 31 December 2006, and will be free for the first six months. THT claim that the connection will be extremely fast.
Risks
For all the convenience of hotspots, they also pose dangers. If your computer isn't properly secured, other network users can "see" it and attempt to gain access. At the very minimum, you need to switch on Windows Firewall, use strong passwords for user accounts ("strong" meaning a complex password consisting of a mix of numbers and letters) and minimize the number of shared folders on your laptop. Seek expert security advice if your computer contains sensitive data.
Advantages Of Wireless Networks
Wireless provides what people are increasingly coming to expect - mobility, convenience, affordability, flexibility and independence.
Wireless cuts down dramatically on those annoying tangles of physical wires, and makes it much easier to move computers from place to place and to add computers to a network. You can work outdoors or at the coffee-shop, or move the laptop to be within earshot of the children after bedtime.
The wireless workspace is no longer defined by location and becomes a concept rather than a physical place.
Wireless Network Performance
Range
Most wireless routers provide coverage of about 100 feet (30.5 meters) in all directions, Walls, doors and metal can reduce the signal. Inexpensive range extenders or repeaters are used to increase the range, for example in a large house.
Signal strength and quality
If the signal is poor, you will be unable to get a connection, or the connection will be intermittent or very slow.
There are a few main culprits to look for if this happens:
- Location of computer in relation to the router - for example, if a large block of metal like a furnace is between the two, the signal will be compromised.
- Interference from other devices that share the same radio frequencies, such as cordless phones, microwaves and baby monitors.
- The number of wireless computers on the network might exceed the specification.
- If there are other networks nearby using wireless connections on the same frequency, this could interfere with your signal.
- High-speed enhancements added to your network (such as those that purport to go up to 108 Mbps or 125 Mbps on an 802.11g device) will affect signals on nearby wireless networks, and will also worsen the effect of neighbouring networks on your signal.
Speed
Wired networks are about ten times faster than wireless, so if you regularly copy large files between computers, wireless is a bad idea. When communicating between a wired and a wireless device, a good rule of thumb is that you can expect to average roughly a third of the data rate advertised on the packaging. This is because of the nature of the technology, network protocols and radio transmissions.
In most cases, wireless won't affect the speed of Internet access, because the limiting factor is the ISP cable connection into your home, and on most networks this connection is slower than both the wireless and wired connections.
Speed and signal are closely linked, so if performance is unexpectedly low, check the signal quality.
You can use Qcheck, a free utility from Ixia, to measure your network speed http://www.ixiacom.com/solutions/display?skey=qcheck.
Security
Many wireless networks are open, meaning that anyone within range can connect to them. This is a seriously bad idea. Wireless networks are open by default, so you need to take active steps to secure them. Try driving around your neighbourhood with a wireless-enabled laptop - you will be shocked at how many unsecured networks there are.
Outsiders simply hitching a free ride on the network may not cause any direct harm, but can slow down Internet or network access. If your ISP charges you for bandwidth, and the hitch-hiker pulls down big files, you will have to pay for their usage.
More seriously, anyone who links into your network hides behind your firewall and looks like you to the outside world. If that individual uses your network for unacceptable or criminal purposes, you might find yourself in trouble with your ISP, or even having to prove your innocence to the police. Unauthorized outside activity can range from unacceptable (junk e-mailing), to malicious (hacking, denial of service attacks), to downright pathological (distributing child pornography).
You can also see why it would be in these people's interest to parasitize on another network and be untraceable to the authorities, so they might well be actively looking for an open network. Don't let it be yours. Apart from the inconvenience and potential harm to you, nobody wants to aid and abet criminal activity through negligence.
Another danger of open networks is that a wireless intruder is coming in behind your Internet firewall, so it's as though they're sitting down at a computer in your house. That means they can cruise around your private documents and access confidential information.
Securing the network
There are two main technologies that keep strangers out of your wireless network. Both are reasonable, but not ultra-secure. Encryption methods password-protect the network. Address filtering requires authorized computers to be actively registered before the network will admit them.
For more robust security, you would need to configure a VPN (virtual private network). This provides a kind of virtual tunnel for your data that can't be seen or hacked easily.
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Sources And Further Information
http://computer.howstuffworks.com/framed.htm?
parent=wireless-network.htm&url=http://www.vicomsoft.com/knowledge/
reference/wireless.html
http://www.pcnineoneone.com/howto/80211bsecurity1.html
http://www.practicallynetworked.com/support/071006wireless_speeds.shtml
http://www.thtelecom.ca/zone-qa.html
