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LM821 User Manual
system can recover from problems faster. RTS packets consume valuable bandwidth,
however, so setting this value too low will limit performance.
Beacon Interval
In addition to data frames that carry information from higher layers, 802.11 includes
management and control frames that support data transfer. The beacon frame, which
is a type of management frame, provides the "heartbeat" of a wireless LAN, enabling
stations to establish and maintain communications in an orderly fashion. Beacon
Interval represents the amount of time between beacon transmissions. Before a
station enters power save mode, the station needs the beacon interval to know when
to wake up to receive the beacon (and learn whether there are buffered frames at
the access point).
Preamble Type
There are two preamble types defined in IEEE 802.11 specification. A long preamble
basically gives the decoder more time to process the preamble. All 802.11 devices
support a long preamble. The short preamble is designed to improve efficiency (for
example, for VoIP systems). The difference between the two is in the Synchronization
field. The long preamble is 128 bits, and the short is 56 bits.
WPA2
It is the second generation of WPA. WPA2 is based on the final IEEE 802.11i
amendment to the 802.11 standard.
Temporal Key Integrity Protocol (TKIP)
The Temporal Key Integrity Protocol, pronounced tee-kip, is part of the IEEE 802.11i
encryption standard for wireless LANs. TKIP is the next generation of WEP, the Wired
Equivalency Protocol, which is used to secure 802.11 wireless LANs. TKIP provides
per-packet key mixing, a message integrity check and a
re-keying mechanism, thus fixing the flaws of WEP.
802.1x Authentication
802.1x is a framework for authenticated MAC-level access control, defines Extensible
Authentication Protocol (EAP) over LANs (WAPOL). The standard encapsulates and
leverages much of EAP, which was defined for dial-up authentication with Point-to-
Point Protocol in RFC 2284. Beyond encapsulating EAP packets, the 802.1x standard
also defines EAPOL messages that convey the shared key information critical for
wireless security.
