ZyXEL Communications NWA-3100, User Manual

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Chapter 8 Other Wireless Configuration
ZyXEL NWA-3100 User’s Guide
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8.4 Configuring Roaming
A wireless station is a device with an IEEE 802.11a/b/g compliant wireless interface. An
access point (AP) acts as a bridge between the wireless and wired networks. An AP creates its
own wireless coverage area. A wireless station can associate with a particular access point
only if it is within the access point’s coverage area.
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 known as
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 other
access points on the LAN about the change. An example is shown in
Figure 65 on page 111 .
With roaming, a wireless LAN mobile user enjoys a continuous connection to the wired
network through an access point while moving around the wireless LAN.
Enable roaming to exchange the latest bridge information of all wireless stations between APs
when a wireless station moves between coverage areas. Wireless stations can still associate
with other APs even if you disable roaming. Enabling roaming ensures correct traffic
forwarding (bridge tables are updated) and maximum AP efficiency. The AP deletes records of
wireless stations that associate with other APs (Non-ZyXEL APs may not be able to perform
this). 802.1x authentication information is not exchanged (at the time of writing).
Figure 65 Roaming Example
The steps below describe the roaming process.
1 Wireless station Y moves from the coverage area of access point AP 1 to that of access
point AP 2 .
2 Wireless station Y scans and detects the signal of access point AP 2 .
3 Wireless station Y sends an association request to access point AP 2 .