ZyXEL Communications ZYAIR, User Manual

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ZyAIR Wireless Gateway Series User’s Guide
6-8 Wireless Configuration and Roaming
In a network environment with multiple access points, wireless stations are able to switch from one access
point to another as they move between the coverage areas. This is roaming. As the wireless station moves
from place to place, it is responsible for choosing the most appropriate access point depending on the signal
strength, network utilization or other factors.
The roaming feature on the access points allows the access points to relay information about the wireless
stations to each other. When a wireless station moves from a coverage area to another, it scans and uses the
channel of a new access point, which then informs the access points on the LAN about the change. The new
information is then propagated to the other access points on the LAN. An example is shown in
Figure 6-6 .
If the roaming feature is not enabled on the access points, information is not communicated between the
access points when a wireless station moves between coverage areas. The wireless station may not be able to
communicate with other wireless stations on the network and vice versa.
Figure 6-6 Roaming Example
The steps below describe the roaming process.
Step 1. As wireless station Y moves from the coverage area of access point AP 1 to that of access point
AP 2 , it scans and uses the signal of access point AP 2 .
Step 2. Access point AP 2 acknowledges the presence of wireless station Y and relays this information
to access point AP 1 through the wired LAN.
Step 3. Access point AP 1 updates the new position of wireless station.
Step 4. Wireless station Y sends a request to access point AP 2 for re-authentication.