Wireless networks are sufficient for accessing the Internet and e-mail programs but with today's higher speed applications usage at the workstation is decreasing. Wireless networks are great for allowing laptop computers or remote computers to connect to the LAN. Wireless networks are also beneficial in older buildings where it may be difficult or impossible to install cables.
Wireless LANs have several disadvantages. They provide poor security, and are susceptible to interference from lights and electronic devices. They are also slower than LANs using cabling. Since most wireless applications are used to access the internet and e-mail, even this slower speed is more than sufficient.
Wireless LANs-Basic information
The most widely used technology for (radio based) wireless LANs is known as Spread Spectrum.
The US military invented this technique to avoid jamming and eavesdropping.
That is good to know because network security is still a concern; a hacker now has to intercept radio transmissions on several frequencies before he/she can even reassemble the packets he/she is trying to intercept.
There are two basic types of Spread Spectrum technology being used:
"frequency hopping spread spectrum (FHSS)" and "direct sequence spread spectrum (DSSS)".
The distinctions are quite technical at this level.
You are saying, "It has to have a catch," aren't you?
There are a couple of small catches.
The main hang up is that, like any other type of radio, interference is a factor of range.
Normal conditions will provide you with a range of up to 100 meters indoors and 300 meters outdoors.
Normal 10base-T Ethernet requires a repeater every 100 meters, so this probably will not affect you any more than your typical wired network would. Again, like any other type of radio signal, steel buildings or locations near power lines may not be suitable for transmission; at least not at the maximum advertised range. You
will have to check.
The next thing that could be a problem for some of you is the bandwidth available.
Most networks do not need bandwidth in excess of 11Mbps; in fact, until recently (prior to 100Mbps Fast Ethernet), Ethernet operated at 10Mbps and the fastest token ring has ever operated at is 16 Mbps.
In most cases you are not going to have Internet access in excess of 11Mbps. Unless you are moving many large files across your intranet or have many machines on each segment of your network, you probably do not need much more than 11Mbps.
Great, so what do you need to make it work?
You will need an access point. This piece of hardware acts as a bridge and a hub combined. On one side it will transmit and receive data to and from your wireless nodes. On the other side it has your garden variety 100Mbps Fast Ethernet for connection to an
Ethernet network, or, via a crossover cable, to a single machine (server, I'm guessing).
This picture is of an access
point by HP
The access point will need power either by P.O.E. (Power Over Ethernet), or the more conventional means of an outlet with in reach of the point's power supply cord.
The picture
is of HP 'injectors' that supply P.O.E. to the W.A.P. (Wireless Access
Point)
For
additional surge protection a device such at The STC-PoE Series is ideally
suited to protect expensive equipment and critical communication/data transfer
from internally generated transients and noise.
Ethernet systems are closed systems. That is, there is no direct connection to either the public communication system or the electrical distribution network. This limits the magnitude and probability of high-energy transients, but does not decrease the probability of internally generated transients. The protection circuitry of the Sola STC-PoE Series provides protection between each conductor in a set, as well as each conductor set for signal circuits
For those of you wondering about DHCP and BootP capabilities, these devices are usually BootP enabled,
so no special configuration for DHCP and BootP clients will be necessary
Next, you will need your client devices.
These are available as either PCMCIA or PCI adapters. These will communicate with the Access
Point's)
to provide your network connectivity (networking, network cards, wireless).
Another thing is the idea of cells (and borrowed from the cellular phone industry).
A cell is the area around an access point that will allow communication with wireless clients.
(ie. Picture the cell as a sphere with the access point at the center. The surface of the sphere would be the same distance away from the center of the sphere as
the effective range of the Access Point.) If you were to overlap cells, you would be able to "roam" between cells with no loss of transmission. Pretty cool, huh?
You may not find much documentation on compatibility amongst manufacturers of these devices.
With that in mind, I believe it would be wise to use components from the same manufacturer
in order to avoid compatibility issues. Some may require additional hardware or software specific to them.
We are sure that when this technology is not so new anymore that this will become less of an issue.
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