Which of the following standards is an amendment to the original IEEE 802.11 and specifies
security mechanisms for wireless networks?
A.
802.11b
B.
802.11e
C.
802.11i
D.
802.11a
Explanation:
802.11i is an amendment to the original IEEE 802.11. This standard specifies security
mechanisms for wireless networks. It replaced the short Authentication and privacy clause of the
original standard with a detailed Security clause. In the process, it deprecated the broken WEP.
802.11i supersedes the previous security specification, Wired Equivalent Privacy (WEP), which
was shown to have severe security weaknesses. Wi-Fi Protected Access (WPA) had previously
been introduced by the Wi-Fi Alliance as an intermediate solution to WEP insecurities. The Wi-Fi
Alliance refers to their approved, interoperable implementation of the full 802.11i as WPA2, also
called RSN (Robust Security Network). 802.11i makes use of the Advanced Encryption Standard
(AES) block cipher, whereas WEP and WPA use the RC4 stream cipher.
Answer option D is incorrect. 802.11a is an amendment to the IEEE 802.11 specification that
added a higher data rate of up to 54 Mbit/s using the 5 GHz band. It has seen widespread
worldwide implementation, particularly within the corporate workspace. Using the 5 GHz band
gives 802.11a a significant advantage, since the 2.4 GHz band is heavily used to the point of
being crowded. Degradation caused by such conflicts can cause frequent dropped connections
and degradation of service.
Answer option A is incorrect. 802.11b is an amendment to the IEEE 802.11 specification that
extended throughput up to 11 Mbit/s using the same 2.4 GHz band. This specification under the
marketing name of Wi-Fi has been implemented all over the world. 802.11b is used in a point-tomultipoint configuration, wherein an access point communicates via an omni-directional antenna
with one or more nomadic or mobile clients that are located in a coverage area around the access
point.
Answer option B is incorrect. The 802.11e standard is a proposed enhancement to the 802.11a
and 802.11b wireless LAN (WLAN) specifications. It offers quality of service (QoS) features,
including the prioritization of data, voice, and video transmissions. 802.11e enhances the 802.11
Media Access Control layer (MAC layer) with a coordinated time division multiple access (TDMA)
construct, and adds error-correcting mechanisms for delay-sensitive applications such as voice
and video.
802.11i