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Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
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Chapter19 Configuring Repeater and Standby Access Points and Workgroup Bridge Mode
Understanding Workgroup Bridge Mode
bridges, that can associate to an access point or bridge. To increase beyond 20 the number of workgroup
bridges that can associate to the access point, the access point must reduce the delivery reliability of
multicast packets to workgroup bridges. With reduced reliability, the access point cannot confirm
whether multicast packets reach the intended workgroup bridge, so workgroup bridges at the edge of the
access point's coverage area might lose IP connectivity. When you treat workgroup bridges as client
devices, you increase performance but reduce reliability. You use the no infrastructure client
configuration interface command to configure access points and bridges to treat workgroup bridges as
simple client devices. This is the default setting.
You should use a workgroup bridge as an infrastructure device if the devices connected to the workgroup
bridge require network reliability equivalent to that of an access point or a bridge. You should use a
workgroup bridge as a client device if these conditions are true:
•More than 20 workgroup bridges associate to the same access point or bridge
•The workgroup bridge associates using an SSID that is not an infrastructure SSID
•The workgroup bridge is mobile
Configuring a Workgroup Bridge for Roaming
If your workgroup bridge is mobile, you can configure it to scan for a better radio connection to a parent
access point or bridge. Use this command to configure the workgroup bridge as a mobile station:
ap(config)# mobile station
When you enable this setting, the workgroup bridge scans for a new parent association when it
encounters a poor Received Signal Strength Indicator (RSSI), excessive radio interference, or a high
frame-loss percentage. Using these criteria, a workgroup bridge configured as a mobile station searches
for a new parent association and roams to a new parent before it loses its current association. When the
mobile station setting is disabled (the default setting) the workgroup bridge does not search for a new
association until it loses its current association.
Configuring a Workgroup Bridge for Limited Channel Scanning
In mobile environments such as railroads, a workgroup bridge instead of scanning all the channels will
be restricted to scan only a set of limited channels in order to reduce the hand-off delay when the
workgroup bridge roams from one access point to another. By limiting the number of channels the
workgroup bridge scans to only those required, the mobile workgroup bridge achieves and maintains a
continuous wireless LAN connection with fast and smooth roaming.

Configuring the Limited Channel Set

This limited channel set is configured using the mobile station scan <set of channels> CLI command
to invoke scanning to all or specified channels. There is no limitation on the maximum number of
channels that can be configured. The maximum number of channels that can be configured is restricted
only by the number of channels a radio can support. When executed, the workgroup bridge only scans
this limited channel set. This limited channel feature also affects the known channel list that the
workgroup bridge receives from the access point to which it is currently associated. Channels are added
to the known channel list only if they are also a part of the limited channel set.