Step 1 |
Disable the 802.11a/n/ac or 802.11b/g/n network as follows:
-
Choose Wireless > 802.11a/n/ac or 802.11b/g/n > Network to open the Global Parameters page.
-
Uncheck the 802.11a (or 802.11b/g) Network Status check box.
-
Click Apply.
|
Step 2 |
Choose Wireless > 802.11a/n/ac or 802.11b/g/n > RRM > DCA 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 controller’s DCA mode:
-
Automatic—Causes the controller to periodically evaluate and, if necessary, update the channel assignment for all joined access points.
This is the default value.
-
Freeze—Causes the controller to evaluate and update the channel assignment for all joined access points, if necessary, but only
when you click Invoke Channel Update Once.
Note
|
The controller does not evaluate and update the channel assignment immediately after you click Invoke Channel Update Once. 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, which is the default value. 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.
Note
|
If your controller supports only OfficeExtend access points, we recommend that you set the DCA interval to 6 hours for optimal
performance. For deployments with a combination of OfficeExtend access points and local access points, the range of 10 minutes
to 24 hours can be used.
|
|
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 |
Check the Avoid Foreign AP Interference check box to cause the controller’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 uncheck 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 |
Check the Avoid Cisco AP Load check box to cause the controller’s RRM algorithms to consider 802.11 traffic from APs in your wireless network when assigning
channels, or uncheck 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 |
Check the Avoid Non-802.11a (802.11b) Noise check box to cause the controller’s RRM algorithms to consider noise (non-802.11 traffic) in the channel when assigning channels
to lightweight access points, or uncheck 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 |
Check the Avoid Persistent Non-WiFi Interference check box to configure the controller to stop ignoring persistent non-Wi-Fi interference in new channel calculation. The
persistent non-Wi-Fi interference is considered during the metric calculation for channels.
|
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 table below.
Table 4. DCA Sensitivity Thresholds
Option
|
2.4-GHz DCA Sensitivity Threshold
|
5-GHz DCA Sensitivity Threshold
|
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.
-
80 MHz—The 80-MHz bandwidth for the 802.11ac radios.
-
160 MHz—The 160-MHz bandwidth for 802.11ac radios.
-
best—It selects the best bandwidth suitable. This option is enabled for the 5-GHz radios only.
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.
|
Step 12 |
Select the Avoid check for non-DFS channel to enable the controller to avoid checks for non-DFS channels. DCA configuration requires at least one non-DFS channel
in the list. In the EU countries, outdoor deployments do not support non-DFS channels. Customers based in EU or regions with
similar regulations must enable this option or at least have one non-DFS channel in the DCA list even if the channel is not
supported by the APs.
Note
|
This parameter is applicable only for deployments having outdoor access points such as 1522 and 1524.
|
|
Step 13 |
In the DCA Channel List area, the DCA Channels field shows the channels that are currently selected. To choose a channel, check its check box in the Select column. To exclude a channel, uncheck 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, 190, 196
802.11b/g—1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
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
Note
|
Depending on the countries configured on the controller, only a subset of
the channels are available.
|
|
Step 14 |
If you are using Cisco Aironet 1520 series mesh access points in your network, you need to set the 4.9-GHz channels in the
802.11a band on which they are to operate. The 4.9-GHz band is for public safety client access traffic only. To choose a 4.9-GHz
channel, check its check box in the Select column. To exclude a channel, uncheck its check box.
The ranges are as follows:
802.11a—1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 26
|
Step 15 |
Click
Apply.
|
Step 16 |
Reenable the
802.11 networks as follows:
-
Choose Wireless > 802.11a/n/ac or 802.11b/g/n > Network to open the Global Parameters page.
-
Check the 802.11a (or 802.11b/g) Network Status check box.
-
Click
Apply.
|
Step 17 |
If you have implemented major changes to your wireless network, such as
installing new APs or changing your channel plan, you must now run the startup
mode. You can do this in the CLI by entering this command:
config {802.11a | 802.11b}
channel global restart
|
Step 18 |
Click
Save Configuration.
Note
|
To see why the
DCA algorithm changed channels, choose
Monitor and then choose
View All under Most
Recent Traps. The trap provides the MAC address of the radio that changed
channels, the previous channel and the new channel, the reason why the change
occurred, the energy before and after the change, the noise before and after
the change, and the interference before and after the change.
|
|