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.
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Unselect the 802.11a (or 802.11b/g) Network Status check box.
-
Click Apply.
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Step 2 |
Choose Wireless > 802.11a/n/ac or 802.11b/g/n > RRM > DCA to open the Dynamic Channel Assignment (DCA) page.
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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, but only when you click
Invoke Channel Update
Once.
Note
|
The Cisco WLC 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.
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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 Cisco WLC 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.
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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.
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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.
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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.
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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.
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Step 9 |
Select the
Avoid Persistent Non-WiFi
Interference check box to enable the Cisco WLC to ignore persistent
non-WiFi interference.
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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 3. DCA Sensitivity
Thresholds
High
|
5 dB
|
5 dB
|
Medium
|
10 dB
|
15 dB
|
Low
|
20 dB
|
20 dB
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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.
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Step 12 |
Select the
Avoid
check for non-DFS channel to enable the Cisco WLC 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.
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Step 13 |
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, 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
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These extended UNII-2 channels in the 802.11a band do not appear in the channel list: 100, 104, 108, 112, 116, 132, 136, and
140. If you have Cisco Aironet 1520 series mesh access points in the -E regulatory domain, you must include these channels in the
DCA channel list before you start operation. If you are upgrading from a previous release, verify that these channels are included in the DCA channel list. To include
these channels in the channel list, select the Extended UNII-2 Channels check box.
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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, select its check box in the Select column. To exclude a channel, unselect 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
The defaults are as follows:
802.11a—20, 26
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Step 15 |
Click
Apply.
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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.
-
Select the
802.11a
(or
802.11b/g)
Network Status check
box.
-
Click
Apply.
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Step 17 |
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.
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