Characteristics of Wireless LANs
The following lists some characteristics of wireless LANs, and the data
transmitted over wireless networks.
■ WLANs use Carrier Sense Multi-Access/Collision Avoidance
(CSMA/CA). Wireless data is half-duplex. CSMA/CA uses Request to
Send (RTS) and Clear to Send (CTS) messages to avoid collisions.
■ WLANs use a different frame type than Ethernet.
■ Radio waves have unique potential issues. They are susceptible to
interference, multipath distortion, and noise. Their coverage area can
be blocked by building features, such as elevators. The signal might
reach outside the building and lead to privacy issues.
■ WLAN hosts have no physical network connection. They are often
mobile and often battery-powered. The wireless network design must
accommodate this.
■ WLANs must adhere to each country’s RF standards.
Clients can roam between APs that are configured with the same
SSIDs/VLANs. Layer 2 roaming is done between APs on the same subnet;
Layer 3 roaming is done between APs on different subnets.