Dynamic Wep - Cisco WAP121 Administration Manual

Wireless
Networks
Cisco Small Business WAP121 and WAP321 Wireless-N Access Point with PoE
- Both Open System and Shared Key. When you select both
authentication algorithms, client stations configured to use WEP in
shared key mode must have a valid WEP key in order to associate with
the WAP device. Also, client stations configured to use WEP as an open
system (shared key mode not enabled) can associate with the WAP
device even if they do not have the correct WEP key.
Static WEP Rules
If you use Static WEP, these rules apply:
• All client stations must have the Wireless LAN (WLAN) security set to WEP,
and all clients must have one of the WEP keys specified on the WAP device
in order to decode AP-to-station data transmissions.
• The WAP device must have all keys used by clients for station-to-AP
transmit so that it can decode the station transmissions.
• The same key must occupy the same slot on all nodes (AP and clients). For
example, if the WAP device defines abc123 key as WEP key 3, then the
client stations must define that same string as WEP key 3.
• Client stations can use different keys to transmit data to the access point.
(Or they can all use the same key, but using the same key is less secure
because it means one station can decrypt the data being sent by another.)
• On some wireless client software, you can configure multiple WEP keys and
define a client station transfer key index, and then set the stations to encrypt
the data they transmit using different keys. This ensures that neighboring
access points cannot decode other access point transmissions.
• You cannot mix 64-bit and 128-bit WEP keys between the access point and
its client stations.

Dynamic WEP

Dynamic WEP refers to the combination of 802. 1 x technology and the Extensible
Authentication Protocol (EAP). With Dynamic WEP security, WEP keys are changed
dynamically.
EAP messages are sent over an IEEE 802. 1 1 wireless network using a protocol
called EAP Encapsulation Over LANs (EAPOL). IEEE 802. 1 X provides dynamically
generated keys that are periodically refreshed. An RC4 stream cipher is used to
encrypt the frame body and cyclic redundancy checking (CRC) of each 802. 1 1
frame.
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