Step 1
| Disable the 802.11a/n or 802.11b/g/n network as follows:- Choose Wireless > 802.11a/n or 802.11b/g/n > Network to open the Global Parameters page.
- 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 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 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.
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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.
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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. |
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-WiFi 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 table below.
Table 1 DCA Sensitivity ThresholdsOption
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2.4-GHz DCA Sensitivity Threshold
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5-GHz DCA Sensitivity Threshold
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High
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5 dB
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5 dB
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Medium
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10 dB
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15 dB
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Low
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20 dB
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20 dB
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Step 11
| For 802.11a/n 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:
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
| 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. |
Step 16
| Reenable the 802.11 networks as follows: Choose Wireless > 802.11a/n 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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