Specifications

Cisco Unified Wireless IP Phone 7921G Series Deployment Guide 31
Using Dynamic Frequency Selection (DFS) on Access Points
For autonomous solution access points, select Dynamic Frequency Selection (DFS) to use auto channel selection.
When DFS is enabled, enable at least one band (bands 1-4).
For unified access points, enable Auto RF unless there is an intermittent interferer in an area which select access points can have
the channel statically assigned.
In case of radar activity, have at least one access point per area that uses a non-DFS channel (UNII-1). This ensures that a
channel is available when an access point’s radio is in its hold-off period while scanning for a new usable channel.
For autonomous access points, enable band 1 only which allows the access point to use only a UNII-1 channel.
For unified access points, can manually select a UNII-1 channel (channels 36, 40, 44, 48) for the desired access points.
A UNII-3 channel (5.745 - 5.805 GHz) can optionally be used if available.
In this diagram, 5 GHz cells use a non-DFS channel while other nearby cells use DFS channels to permit maximum call
capacity under all conditions.
For 5 GHz, 20 channels are available in the Americas and 19 channels in Europe and Japan.
Where UNII-3 is available, it is recommend to use UNII-1, UNII-2 and UNII-3, to utilize a 12 channel set.
If planning to use UNII-2 extended channels (channels 100 - 140), it is recommended to disable UNII-2 (channels 52-64) on the
access point to avoid having so many channels enabled.
Having many 5 GHz channels enabled in the wireless LAN can delay discovery of new access points.
Ch 161
Ch 52
Ch 36
Ch 60
Ch 56
Ch 48
Ch 149
Ch 44
Minimum 20% Overlap