Step 1 |
Disable the 802.11a/n/ac or
802.11b/g/n network as follows:
-
Choose
or
to open the Global Parameters
page.
-
Unselect the
802.11a/n/ac
(or
802.11b/g/n)
Network Status check
box.
-
Click
Apply.
|
Step 2 |
Choose
or
to open the Dynamic Channel Assignment (DCA)
page.
|
Step 3 |
Choose one of the following options from the
Channel Assignment Method drop-down list to specify
the Cisco WLC’s DCA mode:
-
Automatic—Causes the Cisco WLC to periodically evaluate and,
if necessary, update the channel assignment for all joined access points. This
is the default value.
-
Freeze—Causes the Cisco
WLC to evaluate and update the channel assignment for all joined access points,
if necessary, only when you click
Apply after selecting the
Freeze option.
Note
|
The Cisco WLC does not
evaluate and update the channel assignment immediately when you click
Apply after selecting the
Freeze option. It waits for the next interval to
elapse.
|
-
OFF—Turns off DCA and sets all access point radios to the
first channel of the band. If you choose this option, you must manually assign
channels on all radios.
Note
|
For optimal performance, we
recommend that you use the Automatic setting.
|
|
Step 4 |
From the Interval drop-down list, choose one of the
following options to specify how often the DCA algorithm is allowed to run:
10 minutes,
1 hour,
2 hours,
3 hours,
4 hours,
6 hours,
8 hours,
12 hours, or
24 hours. The default
value is 10 minutes.
|
Step 5 |
From the AnchorTime drop-down list, choose a number to
specify the time of day when the DCA algorithm is to start. The options are
numbers between 0 and 23 (inclusive) representing the hour of the day from
12:00 a.m. to 11:00 p.m.
|
Step 6 |
Select the
Avoid Foreign AP
Interference check box to cause the Cisco WLC’s RRM algorithms to consider
802.11 traffic from foreign access points (those not included in your wireless
network) when assigning channels to lightweight access points, or unselect it
to disable this feature. For example, RRM may adjust the channel assignment to
have access points avoid channels close to foreign access points. The default
value is selected.
|
Step 7 |
Select the
Avoid Cisco AP Load
check box to cause the Cisco WLC’s RRM algorithms to consider 802.11 traffic
from Cisco lightweight access points in your wireless network when assigning
channels, or unselect it to disable this feature. For example, RRM can assign
better reuse patterns to access points that carry a heavier traffic load. The
default value is unselected.
|
Step 8 |
Select the
Avoid Non-802.11a (802.11b)
Noise check box to cause the Cisco WLC’s RRM algorithms to consider noise
(non-802.11 traffic) in the channel when assigning channels to lightweight
access points, or unselect it to disable this feature. For example, RRM may
have access points avoid channels with significant interference from nonaccess
point sources, such as microwave ovens. The default value is selected.
|
Step 9 |
Select the
Avoid Persistent Non-WiFi
Interference check box to enable the Cisco WLC to ignore persistent
non-Wi-Fi interference.
|
Step 10 |
From the DCA Channel
Sensitivity drop-down list, choose one of the following options to specify
how sensitive the DCA algorithm is to environmental changes such as signal,
load, noise, and interference when determining whether to change channels:
-
Low—The DCA algorithm is not particularly sensitive to
environmental changes.
-
Medium—The DCA algorithm is moderately sensitive to
environmental changes.
-
High—The DCA algorithm is highly sensitive to environmental
changes.
The default value is
Medium. The DCA sensitivity thresholds vary by radio band, as noted in the
following table:
Table 1. DCA Sensitivity
Thresholds
High
|
5 dB
|
5 dB
|
Medium
|
10 dB
|
15 dB
|
Low
|
20 dB
|
20 dB
|
|
Step 11 |
For 802.11a/n/ac networks only, choose one of the
following channel width options to specify the channel bandwidth supported for
all 802.11n radios in the 5-GHz band:
-
20 MHz—The
20-MHz channel bandwidth (default)
-
40 MHz—The
40-MHz channel bandwidth
Note
|
If you choose 40 MHz, be
sure to choose at least two adjacent channels from the DCA Channel List in
Step
13 (for example, a primary channel of 36 and an extension channel of 40).
If you choose only one channel, that channel is not used for 40-MHz channel
width.
|
Note
|
If you choose 40 MHz, you
can also configure the primary and extension channels used by individual access
points.
|
Note
|
To override the globally
configured DCA channel width setting, you can statically configure an access
point’s radio for 20- or 40-MHz mode in the 802.11a/n Cisco APs > Configure
page. if you then change the static RF channel assignment method to WLC
Controlled on the access point radio, the global DCA configuration overrides
the channel width configuration that the access point was previously using. It
can take up to 30 minutes (depending on how often DCA is configured to run) for
the change to take effect.
|
Note
|
If you choose 40 MHz on the
A radio, you cannot pair channels 116, 140, and 165 with any other channels.
|
-
80 MHz—The
80-MHz bandwidth for the 802.11ac radios.
Note
|
If you choose 80 MHz, be
sure to choose four adjacent channels from the DCA Channel List in
Step
13 (for example, a primary channel of 36 and an extension channel of 40).
If you choose only one channel, that channel is not used for 40-MHz channel
width.
|
Note
|
If you choose 80 MHz, you
can also configure the primary and extension channels used by individual access
points.
|
Note
|
To override the globally
configured DCA channel width setting, you can statically configure an access
point’s radio for 20-, 40-, or 80-MHz mode on the 802.11a/n Cisco APs >
Configure page. if you then change the static RF channel assignment method to
WLC Controlled on the access point radio, the global DCA configuration
overrides the channel width configuration that the access point was previously
using. It can take up to 30 minutes (depending on how often DCA is configured
to run) for the change to take effect.
|
Note
|
If you choose 40 MHz on the
A radio, you cannot pair channels 116, 140, and 165 with any other channels.
|
This page also shows the
following nonconfigurable channel parameter settings:
-
Channel Assignment Leader—The MAC address of the RF group
leader, which is responsible for channel assignment.
-
Last Auto Channel Assignment—The last time RRM
evaluated the current channel assignments. This is used only for RF leader and
not for the RF member.
|
Step 12 |
In the DCA Channel List area, the DCA Channels text box
shows the channels that are currently selected. To choose a channel, select its
check box in the Select column. To exclude a channel, unselect its check box.
The ranges are as follows:
-
802.11a—36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116,
132, 136, 140, 149, 153, 157, 161, 165 (depending on countries).
-
802.11b/g—1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
(depending on countries).
The defaults are as follows:
-
802.11a—36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116,
132, 136, 140, 149, 153, 157, 161
-
802.11b/g—1, 6, 11
|
Step 13 |
Click
Apply.
|
Step 14 |
Reenable the
802.11 networks as follows:
-
Choose
or
to open the Global Parameters
page.
-
Select the
802.11a/n/ac
(or
802.11b/g/n)
Network Status check
box.
-
Click
Apply.
|
Step 15 |
Click
Save Configuration.
|