Appendix B - About Wireless LANs

performance. This capability is called Roaming. (Access Points do not have or require Roaming capabilities.)

Channels

The Wireless Channel sets the radio frequency used for communication.

•Access Points use a fixed Channel. You can select the Channel used. This allows you to choose a Channel which provides the least interference and best perform- ance. In the USA and Canada, 11 channel are available. If using multiple Access Points, it is better if adjacent Access Points use different Channels to reduce inter- ference.

•In "Infrastructure" mode, Wireless Stations normally scan all Channels, looking for an Access Point. If more than one Access Point can be used, the one with the strongest signal is used. (This can only happen within an ESS.)

•If using "Ad-hoc" mode (no Access Point), all Wireless stations should be set to use the same Channel. However, most Wireless stations will still scan all Chan- nels to see if there is an existing "Ad-hoc" group they can join.

WEP

WEP (Wired Equivalent Privacy) is a standard for encrypting data before it is transmit- ted.

This is desirable because it is impossible to prevent snoopers from receiving any data which is transmitted by your Wireless Stations. But if the data is encrypted, then it is meaningless unless the receiver can decrypt it.

If WEP is used, the Wireless Stations and the Access Point must have the same settings for each of the following:

WEP

Off, 64 Bit, 128 Bit

 

 

Key

For 64 Bit encryption, the Key value must match.

 

For 128 Bit encryption, the Key value must match

WEP Authentication

Open System or Shared Key.

 

 

WPA-PSK

WPA-PSK is another standard for encrypting data before it is transmitted. This is a later standard than WEP (Wired Equivalent Privacy), and provides greater security for your data. Data is encrypted using a 256Bit key which is automatically generated and changed often.

If all your Wireless stations support WPA-PSK, you should use this instead of WEP.

If WPA-PSK is used, the Wireless Stations and the Access Point must have the same settings for each of the following:

WPA PSK

Enter the same value on every station and the AP.

(Pre-shared Key)

The PSK must be from 8 to 63 characters in length.

 

The 256Bit key used for the actual encryption is de-

 

rived from this key.

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