CompTIA Network+ Training Kit: Wireless Networking

Chapter Summary

• The wireless LAN equipment on the market today is based on the 802.11 standards published by the Institute of Electrical and Electronics Engineers (IEEE). Because the protocols are produced by the same standards body, the 802.11 wireless technology fits neatly into the same layered structure as the Ethernet specifications.

• The IEEE 802.11a amendment fundamentally changed the technology by adding the 5-GHz band.

• The 802.11b document increases the transmission speed to as much as 11 Mbps.

• The IEEE 802.11g amendment built on the 802.11b technology by adopting the OFDM modulation from 802.11a while retaining the 2.4-GHz frequency from 802.11b.

• The IEEE 802.11n amendment introduces a number of modifications to the technology, including the potential doubling of channel widths and the addition of the 5-GHz frequency band from 802.11a to the standard 2.4-GHz band from 802.11b/g.

• Multiple-Input Multiple-Output (MIMO) is a physical layer enhancement that enables wireless devices to multiplex signals over a single channel simultaneously.

• Frame aggregation is a technique that combines the payload data from several smaller frames into one larger frame.

• The fundamental building block of an 802.11 wireless LAN is the basic service set (BSS). A BSS is a geographical area in which properly equipped wireless stations can communicate.

• An arrangement in which all of the network devices in the BSS are mobile or portable is called an ad hoc topology.

• The service set identifier (SSID) is a 32-bit string that identifies a BSS and all its members.

• The 802.11 standard defines the use of a MAC mechanism called Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), which is a variation of the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) mechanism used by Ethernet.