Persistent Channel 13 Dynamic Channel Assigment (DCA)

Dear WiFi Experts,
Why is AP still choosing channel 13 when Dynamic Channel Assigment is enabled and channels 1,6,11 are the only channels selected/checked in the DCA list?
Can't the AP choose only 1, 6, and 11 and nothing more?
WLC country code is set to SA (Saudi Arabia).
WLC code 7.0.98

HI ,
It chooes the best channel.
Just info:
Here is the list of channels (and frequencies) of the ISM (industrial, scientific and medical band) (2.4 GHz) used in the WiFi technology:
Channel 1: 2.412 MHz
Channel 2: 2.417 MHz
Channel 3: 2.422 Mhz
Channel 4: 2.427 Mhz
Channel 5: 2.432 Mhz
Channel 6: 2.437 Mhz
Channel 7: 2.442 Mhz
Channel 8: 2.447 Mhz
Channel 9: 2.452 Mhz
Channel 10: 2.457 MHz
Channel 11: 2.462 MHz
Channel 12: 2.467 MHz
Channel 13: 2.472 MHz
Channel 14: 2.484 MHz
If you want then you can manually change Channle per AP:
Here is the process:
1. Login WLC GUI
2. Go to Wireless > Access Points > 802.11a/802.11b then on far right side of AP from drop dpwn menu click on configure.
Under RF channel assignment you can change the channle manually.
Regards
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Sabhasin,
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Service and Function Objectives
Solutions shall define mechanisms to provide the service listed below.
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Hello Everyone.
I want to say thank you for read my post.
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Source: http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/71113-rrm-new.html
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Questions on the Wireless Installation.

Experts,
We have a good number of wireless access point installed on our network and I want to make sure that these AP's are not conflicting with each other.
Why do all the wireless access points show me the channel as 1(for 2.4 GHz)? and channel 36(for 5GHz)?
If I run a WiFi analyses what does the singnal strength in dBm really indicate? Is -70 good?
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You can configure your WLC for Radio Resource Manager (RRM) and Dynamic Channel Assignment (DCA).
The radio resource management (RRM) software embedded in the controller acts as a built-in RF engineer to consistently provide real-time RF management of your wireless network.
RRM automatically detects and configures new controllers and lightweight access points as they are added to the network. It then automatically adjusts associated and nearby lightweight access points to optimize coverage and capacity.
The controller's dynamic channel assignment (DCA) capabilities are also useful in minimizing adjacent channel interference between access points. For example, two overlapping channels in the 802.11b/g band, such as 1 and 2, cannot both simultaneously use 11/54 Mbps. By effectively reassigning channels, the controller keeps adjacent channels separated.
Check more details on RRM and DCA in document.
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1. Do I configure each AP to non overlapping neighbor channels(1,6,11 for 2.4GHz) or leave that to controller to decide?
Let the controller(s) decide. By default the Dynamic Channel Assignment (DCA) verifies the channel for interferrence every 600 seconds. Because you have 3500 then make sure you enable Event Driven RRM (Radio Resource Management) on both channels.
Does controller change the channel of an AP when it sees congestion on a specific frequency?
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Sure.
What frequency to use for neighboring APs? OR again, leave it to controller to shift as needed?
Leave this option in default.
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Can config. influence this?
Regards, MH

Hi Mark,
Hope all is well with you :) The answer to this question is not really. Have a look at why this is;
RF Group Leader
The members of an RF group elect an RF group leader to maintain a "master" power and channel scheme for the group. The RF group leader is dynamically chosen and cannot be selected by the user. In addition, the RF group leader can change at any time, depending on the RRM algorithm calculations.
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The RF Group Name is an ASCII string configured per wireless LAN controller (WLC). The grouping algorithm elects the RF Group leader that, in turn, calculates the Transmit Power Control (TPC) and Dynamic Channel Assignment (DCA) for the entire RF Group. The exception is Coverage Hole algorithm (CHA), which is run per WLC. Because RF Grouping is dynamic, and the algorithm runs at 600-second intervals by default, there might be an instance where new neighbors are heard (or existing neighbors are no longer heard). This causes a change in the RF Group that could result in the election of a new Leader (for one or multiple logical RF Groups). At this instance, the Tx Power Threshold of the new group leader is used in the TPC algorithm. If the value of this threshold is inconsistent across multiple controllers that share the same RF Group Name, this can result in discrepancies in resultant Tx power levels when the TPC is run.
From this good doc;
Radio Resource Management under Unified Wireless Networks
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a008072c759.shtml
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Rob

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It's also possible DCA is disabled on the WLC, check it under:
802.11a > RRM > Dynamic Channel Assignment (DCA)
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802.11a > RRM > Tx Power Control(TPC)
Nabil

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I see this message come in from Cisco Prime every now and then on a 1242. I see other people have asked the question a few years ago. Has anyone else taken a look and figured out what the problem was?
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This sounds like Dynamic Channel Assignment (DCA) at work.
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Content admin - iview not in top level navigation bar

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Persistent Channel 13 Dynamic Channel Assigment (DCA)

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