This document describes how to configure the wireless client in order
to minimize delays when roaming from access point to access point.
There are no specific requirements for this document.
The information in this document is based on these software and
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
Technical Tips Conventions for more information on document
Complete these steps in order to minimize delays when roaming from
access point to access point when you use the CB21AG/PI21AG (802.11a/b/g
wireless client adapter).
Note: These steps optimize roaming delays at the driver layer and are
applicable to all authentication types. If 802.1x authentication is used, there
might be additional optimizations possible, which are outside the scope of this
Note: Optimizing for faster roaming can potentially contribute to increased
battery use and to reduced throughput.
Use ADU client software version 4.4 or later.
Set the BSS Aging Interval to 30, and set the Scan
Valid Interval to 20.
Complete these steps in order to set these two parameters via the
Windows control panel:
Go to Windows Explorer.
Right-click My Network
Choose Properties from the drop-down
Right-click Wireless Network Connection#, where
# is the instance number of the Cisco CB21AG Wireless LAN
Choose Properties from the drop-down list. The
Wireless Network Connection Properties dialog box appears.
Click the Advanced tab.
Set the BSS Aging Interval to 30, and set the
Scan Valid Interval to 20.
These parameter values are the absolute lowest permitted values and
should not be set any lower. The default values are 120 for BSS Aging Interval
and 60 for Scan Valid Interval.
If your access point coverage permits it, configure the client
profile in the ADU only to use the 5 GHz (802.11a) or 2.4
GHz (802.11b/g) band, not both. In order to configure the client profile,
complete these steps:
Launch the ADU client software.
Click the Profile Management tab, highlight the
profile of interest, and click Modify.
Click the Advanced tab.
Under Wireless Mode, uncheck the rates that you do not intend to
If you do not use the ADU to manage the CB21AG, you must use
registry settings in order to select the rates. Complete these
Choose Start > Run, and type
regedit in order to launch the Registry
Navigate to HKEY_LOCAL_MACHINE > System >
CurrentControlSet > Control > Class >
4D36E972-E325-11CE-BFC1-08002bE10318 folder, and choose
Type NetBand in the search field in order to
locate the NetBand variable. This is under an [instance]
four-digit subkey that has a DriverDesc value of Cisco Aironet
802.11a/b/g Wireless Adapter.
The NetBand REG_SZ variable is a bitmask of supported rates. By
default this is 15. The values are:
(not used) 0x02
(not used) 0x10
For example, in order to support only 11b and 11g rates, this
is 0x04 + 0x08 = 0x0C = 12 decimal.