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New Member

Many AP on same (1) Channel (TPC / DCA Auto)

Hi experts,

I have WLC 5508 v8.0.140.0 who manages 50 AP in WH

My problem is that many neighbours AP are in channel 1 and my clients are facing interrupted roaming - disconnections

 

Well I have already seen this when AIR-CAP2702E-E-K9 is used, antennas were not fixed correctly so AP could not see them each other and naturally all stayed in Channel 1 TxPow 1

 

But now  i have AIR-CAP2702I-E-K9, so how is it possible ?

I scheduled an auto DCA/TPC Update and increased the Min TxPow to make them see each other, but nothing changes.

What do I miss ? I can't have  HW problem on half of my AP's.

 

Where the WLC is misconfigured ? It should detect and change the values automatically , that's why we by Cisco.

WLCCA shows some "health problem" on few AP, how do he checks that ? Can I trust it ?

Thanks for any help, it's getting red hot

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Gold

CleanAir will detect and

CleanAir will detect and classify interferers.

EDRRM will allow the WLC to change channels and/or lower the power of the AP to minimize the effects of co-channel interference. 

33 REPLIES
Hall of Fame Super Gold

Is CleanAir and EDRRM enabled

Is CleanAir and EDRRM enabled?

New Member

Thanks for response,

Thanks for response,

Not for now.

CleanAir will be activated at 12h (I planned this) but not EDRRM.

Should I enable it also ? I don't know this feature, what will get better with it ?

Hall of Fame Super Gold

CleanAir will detect and

CleanAir will detect and classify interferers.

EDRRM will allow the WLC to change channels and/or lower the power of the AP to minimize the effects of co-channel interference. 

New Member

Thanks

Thanks

I'll give you a feedback in the end of the day

PS: "EDRRM will allow the WLC to change channels and/or lower the power of the AP to minimize the effects of co-channel interference"

Correct me if I'm wrong, but WLC is already doing this without EDRRM. Isn't he ?

Hall of Fame Super Gold

but WLC is already doing this

but WLC is already doing this without EDRRM. Isn't he ?

If DCA & RRM are both enabled, the WLC will change channels (DCA) and/or Tx power (RRM) to joined AP to "de-conflict" potential co-channel interference of itself.  EDRRM is totally different because the APs themselves will look at other WiFi interference and react accordingly.

New Member

OK thanks for clarifing to me

OK thanks for clarifing to me.

CleanAir activated but doesn't get better....

on open space (9500m2)I haev 5 AP. 4/5 are in channel 1 TxPow 3.

WLC should detect this and manage it correctly.

I miss something but can't find what. I'll maybe change the AP

New Member

I just noticed that my 2nd

I just noticed that my 2nd WLC is Auto-Leader and the one who has most of the AP's is a member...does it change anything ?

Hall of Fame Super Silver

When you have multiple

When you have multiple controllers in an RF group, one is always going to be the leader.  This shouldn't matter at all. Now on the 2.4ghz, you only have three channels to use and there is always a chance that you have neighbor AP's on the same channel, 5ghz is different. So the question is, are your clients dual band or not?  If so, you should look at client band select and adjusting the threshold to push the client to the 5ghz.  If you have clients that are 2.4ghz only, then you need to use a tool to look at the environment also. If you are in a shared tenant space, RRM is probably doing its job because of the neighboring AP's.  Tools can also show you the channel utilization, how many 802.11 and non-802.11 interference there are etc.  

From one of the AP's you can issue a show AP auto-RF 802.11b <AP name> and look how many neighbors that AP's seeing and the TX power.  Also you can see the number of clients and the channel utilization.  Make sure the list of neighbors is correct or else you might be running into a bug or possibly AP's that are mis-labeled.

-Scott 

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-Scott
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New Member

Thanks Scott,

Thanks Scott,

My clients are not dual band, only 2.4GHz.

I put in attachement the output for 3 neigbours AP in same cellule

AP330 <> AP328 <> AP329

all on open space in 65 - 75 meters.

WLC TPC Auto Max 30 Min 7 / DCA Auto

How can I exploit this output / file ?

Hall of Fame Super Silver

I do t see any attachments

I do t see any attachments but remember that RRM requires an AP to hear 4 AP's or more. If your AP's are spread apart, then RRM might not be working for you.  So that is why you need to look at the output and hopefully you see neighbor AP's with a good rssi.  

Remember that RRM will place AP's on a channel that it believes is the best.  You need to understand the RF on the 2.4ghz to be honest.  Get some free tools that look at the spectrum and go to various areas and see how congested the 2.4ghz is. Your trying to improve the user experience on the 2.4ghz but if the 2.4ghz is very congested, there will be nothing much you can do.  You also need to identify other source of interference on the 2.4ghz in the areas users complain.

-Scott

*** Please rate helpful posts ***  

-Scott
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Hall of Fame Super Silver

You should also check the

You should also check the client count per AP.  If your going above 30 for example, you might need to add access points.  We have open space also and our AP's are probably 75' at most so we cover for density. However we have to disable the 2.4ghz on AP's to reduce the channel utilization from our own AP's and external 2.4ghz AP's and interference.

-Scott 

*** Please rate helpful posts *** 

-Scott
*** Please rate helpful posts ***
New Member

OK Thanks to all.

OK Thanks to all.

For now this strange behavion remains but i'll try to manage it out.

Something wrong with the RRM, but i don't know how to t-shoot.

Kepp you informed

Hall of Fame Super Silver

You need to look at the

You need to look at the existing environment.  If there are neighboring APs from adjacent tenants, that can be your issue.  If your 5ghz is working fine and the channels are good, then I would say RRM is fine.  If you don't like what RRM is assigning on the 2.4ghz, then you have a choice if manually assigning channels. Find some free tools and go to the area and see how many other AP's besides yours are on adjacent channels. That is what you need to do to troubleshoot. 

-Scott 

*** Please rate helpful posts *** 

-Scott
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New Member

Hi all :)

Hi all :)

Well,

- I checked physicaly the AP & antenas > NO Problem

- I checked sh int xxx to see if some errors are occuring on the port (never knows)

- I assigned manualy the channels for some of the AP to get better channel distribution

When I put these same AP on auto mode they just came back to a wrong channel !

Can a WLC restart resolve something ? I'm out of ideas :(

Bronze

Maybe your APs are too far

Maybe your APs are too far apart and don't see each other, so they all default to 1 ?

New Member

Thanks all

Thanks all

I'll be on site next Monday.

I'm using inssider.

If you have some advice that was not mentioned yet, I’ll take it

New Member

Hi everyone

Hi everyone

I've been on site... and found no logic.

AP's are on good distance to see themself...

No important obstacles, but still some neigbours are on same channel.

I even changed an AP and antenna to see if it is not an invisible HW problem issue

I have many dis connections.

In lack of ideas i'll  do a manual setup by this makes me worry, I'm missing out something

New Member

I can't find the solutionI'll

I can't find the solutionI'll upgrade IOS and switch for 802.11g

topic closed

Thanks all

If you're on Android for your

If you're on Android for your cell phone, get something like WiFi Analyzer to see what channels are used in both the 2.4 and 5 Ghz bands.  If all your neighbors have switched to 6, 11; then the best channel for you to use might actually BE 1.

Anyway, a view of channel usage is a starting point.

New Member

Hi Leo,

Hi Leo,

I have kinda similar issue. DCA works fine for APs on 2 levels and I can see 40MHz channels assigned to APs.

But on another level, all APs are assigned 20MHz channels (either 36 or 56).

All the APs are in same AP Group.

What am I missing?

Hall of Fame Super Gold

But on another level, all APs

But on another level, all APs are assigned 20MHz channels (either 36 or 56).

All the APs are in same AP Group.

What am I missing?

Check each individual APs' configuration.  Maybe someone statically assigned the APs to operate on 20 Mhz.

New Member

Checked again on individual

Checked again on individual APs, they show channel width 'Globally Configured' with an asterisk * next to them.

Hall of Fame Super Gold

What firmware are they on?

What firmware are they on?

New Member

Running 8.3.102.0

Running 8.3.102.0

Hall of Fame Super Gold

Uhhhh ... Upgrade first.  

Uhhhh ... Upgrade first.  

Hall of Fame Super Silver

To add to Leo's comments, I

To add to Leo's comments, I have seen things like this in the past. Have you tried to statically set it to 40 and then set it back to global?  That usually will fix the issue as it may be a glitch.

-Scott 

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-Scott
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New Member

Would this change restarts

Would this change restarts APs and/or WLC?

Hall of Fame Super Silver

No... you are making a change

No... you are making a change to a specific AP. You first would set the channel and then set it to 40mhz. Apply that and then set it back to global.

-Scott 

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-Scott
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New Member

It worked actually.

It worked actually.

I have 25 APs, guess I'd have to do it manually on all of them.

Also, it worked on Radio Slot 1.

What about Dual Band Radio?

Can't make same changes to them.

P.S. We have set Radio Role Assignment manually to serve clients in 5 GHz.

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