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What is the "default" RRM channel?

Let's pretend you have a brand new building with brand new controllers and access points and you put it all together and make it work.  If there are no clients in the building, the access points will not have the channels and power levels changed via RRM.

I read somewhere in the recent past there is a default channel.  I thought I read the access points will go to full power and sit on the highest channel out of the DCA list.

Does anyone know what the "default" channel is?  Do they boot up and sit on the high or low channels?

Thanks in advance...

12 REPLIES
Hall of Fame Super Silver

What is the "default" RRM channel?

If you have TPC and DCA disabled, the AP will default to channel 36 and channel 1.  IF 40mhz channel is used then the AP will default to channel 36 & 40. As for power, You can freeze TPC, but it will reduce TX power only once.  SO if you have a lot of ap's you can see TX power of 1-8.

-Scott
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New Member

Re: What is the "default" RRM channel?

Do you recall where you found that information, by chance?

Hall of Fame Super Silver

Re: What is the "default" RRM channel?

I tested it with a 1142. 1252, 1941w, and 3600. I disabled RRM and bounced all the AP's.

Thanks,

Scott Fella

Sent from my iPhone

-Scott
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Hall of Fame Super Silver

Re: What is the "default" RRM channel?

Now if I was going to migrate from an existing wireless network to a Cisco wireless, I would by default have RRM enabled, but have the network disabled. So when I'm ready to bring up the new network, the existing is shut down while I just have to enable the network.

Thanks,

Scott Fella

Sent from my iPhone

-Scott
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New Member

Re: What is the "default" RRM channel?

In my case, I have an old building without any WiFi in it. I am verifying coverage using Survey Pro, and proving it with AirWise. Everything looks good with the exception of channel interference.

My theory was that RRM needed to have a bakeoff, so I asked some folks to bring some 5GHz clients into the building, and they placed them all on the 6th floor. That’s the floor with the interference from other adjacent channels. I figured that RRM would start to make changes once it saw three clients, etc, etc.

That is when I remembered reading somewhere that the APs actually default to a channel when they boot up and RRM hasn’t done anything yet. I recalled it being the high channels or low channels, or something like that. If the co-channel interference is on 36, then we’ll know that RRM hasn’t done anything because there are no clients.

Agree? I must admit my logic could be flawed along the way…

P.S. Must be nice to have that little lab of yours. J

Hall of Fame Super Silver

Re: What is the "default" RRM channel?

With RRM disabled, it doesn't matter if you have clients or not, the channels are not going to change unless you manually change the channel.  If you are doing some sort of post survey, set rrm and let it settle for a couple hours and then turn it off or set to freeze.

-Scott
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New Member

Re: What is the "default" RRM channel?

RRM is enabled and always has been. I recall reading how the RRM algorithm works, and it needs a certain number of clients in order for the channel and power to change, if memory serves me correctly.

So, when you have a new wlan with no clients, theoretically RRM won’t do anything. The APs should go to channel 36 and sit there until clients arrive and then it can do its magic. My question was… what is that channel, and I think we came to the conclusion that is channel 36.

I will go take a look at my floors and channels to see the power and channel selection.

Hall of Fame Super Gold

Re: What is the "default" RRM channel?

Just want to add to Scott's post that with the new 7.2.X code (and future codes), DCA and TPC will be sporting a brand new algorythm.  Currently, TPC 2.0 is recommend as "do not use ... yet".

New Member

Re: What is the "default" RRM channel?

A new algorithm, eh? You first. Haaaahhhhh.

Hall of Fame Super Silver

Re: What is the "default" RRM channel?

RRM should adjust the channels due to the fact it will hear the other AP's. Yes on the 5ghz the channel is 36 and on the 2.4ghz it's 1. Now if your talking about TPC, then coverage hole detection can make an ap increase or decrease the TC power. Your channels should change unless something is wrong. there was an issue with an older code and RRM not working, but I have not had an issues with any of the code in the 5508 with RRM not working. Bounce the wlc.

Sent from Cisco Technical Support iPhone App

-Scott
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New Member

Re: What is the "default" RRM channel?

Sometimes we don't bounce the controller, but accidentally trip on the power cord instead.

Hall of Fame Super Silver

Re: What is the "default" RRM channel?

That's how it's done:)

Thanks,

Scott Fella

Sent from my iPhone

-Scott
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