WLC 5508 multiple country codes, limitations

[Stefan Engel]

Hi CSC,

Currently we are running 2x 5508 (7.2.111.3) in our Regional DC and all AP's from APAC are connected in H-REAP mode.

On each WLC the following country codes are configured:

Configured Country Code(s):

CN, ID, IN, J2, J3, J4, JP, KE, KR, PH, PH2, TH, TW

Regulatory Domain:

802.11a:      -ACEJKNPTU

802.11bg:    -ACEJP

We have some sites (mainly China), which facing issues on WLAN recently (slow performance, weak signal..etc.

RF & power level are 'managed' by WLC.

After reviewieing some sites with our vendor, the feedback to improve stability/perfromace, was to either run just 1 country code/WLC..or set RF/power level manually for each AP. (which of course would be an admin nightmare!!)

I havent found the same information on cisco.com & thought connecting AP's from different country's to the same WLC works well (incl. having the WLC manage power/rf)?

Are there any limitations, when having multiple country codes on same WLC?

Appreciate your feedback.

Thanks,

Stefan

[Jacob Snyder · Accepted solution]

One thing to remember when running multiple country codes is that you always run the lowest common setting. You could improve things by splitting the APs up by country and only run specific countries on certain controllers.

The other thing is making sure that your AP placement is conducive to RRM deciding your power levels. For example, APs all placed in a row down a hallway will power down to low levels based on how well they see each other.

You can tune the RRM settings for a particular site by leveraging AP and RF groups, that way you can alter the TPC thresholds for each site.

Sent from Cisco Technical Support iPhone App

[Flavio Boniforti]

Hi Jacob,

RRM is not to be used - it won't ever work right, wether it's Cisco or with any other vendor.

The right approach is static channel plan.

F.

[Brian Taylor]

RRM works fine with altering the min/max RRM power limits. If RRM is not working for you, that is a design issue.

Now that FRA is out, static configuration is even less ideal. In newer code Cisco is optimizing TPC for 5Ghz by making it CCI aware.

[Brian Taylor]

RRM works fantastic if you tune its settings and do a proper design.

[Leo Laohoo · Accepted solution]

Stephan,

Running multiple country codes in a single WLC is a bad idea.   Only common channels will be allowed.  Power will also be curtailed to the most common one.

The best thing is to get another WLC and group them by using the same regulatory domain. 

[Flavio Boniforti]

Hi Leo,

can you explain why this is as you describe it? I mean: why is it possible to enable multiple country codes (regulatory domains) on the same WLC but then you got the limitations of being restricted/reduced to the lowest common settings?

I'm facing this setup with an 8.2 IOS on a 5508 WLC which serves APs in different countries and regions (NL, BE, RU, CH, IT, BG at least).

Thanks for your help and best regards,

Flavio.

[Leo Laohoo]

why is it possible to enable multiple country codes (regulatory domains) on the same WLC but then you got the limitations of being restricted/reduced to the lowest common settings?

It's common sense.  Let say you have an AP with -B and another with -E.  Both APs will join the controller fine, however, both APs will only operate in channels and power settings common to both Regulatory Domain.  

I'm facing this setup with an 8.2 IOS on a 5508 WLC which serves APs in different countries and regions (NL, BE, RU, CH, IT, BG at least).

They are different countries but they all far under one big Regulatory Domain, -E.  So this means the APs deployed in these countries will be fine.

[Flavio Boniforti]

Hi Leo.

Sorry but I don't see any "common sense" other than marketing-driven setups. Cisco wanting the end customer to buy one controller per regulatory domain.

Let's say I have APs in -B and APs in -E regulatory domains. Of course my WLC will allow both APs to join. But there's no rational reason for them only being able to operate in channel/power settings common to both regulatory domains. It is simply a matter of not having this "intelligence" in the WLC, because there are use cases in which a company has one WLC (maybe redundant in HA) and has APs managed from it all over the world. So I'd expect the WLC to allow the -B APs to use the corresponding channel/power settings, and the same with -E APs. Why would a WLC limit this functionality?

Also, you're wrong: the mentioned countries do not share the same regulatory domain. RU has -R reg. domain. So in my case I need both reg domains (-E and -R).

[Brian Taylor]

Even in 8.2 it seems it will use common power and channel.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-2/config-guide/b_cg82/b_cg82_chapter_01111010.html?bookSearch=true

[Manish Mathur]

Hi All,

Going by this thread and also my personal experience with multiple country codes allowed on a single WLC , I did a bit of research and testing in the Wi-Fi environment.

The results:

1. In the 8.2 code (not sure since what version of code but I guess at least after 7.4) , there is no such concept of "common denominator" for channels or power.

2. In a setup where we have APs in Taiwan and Copenhagen connected to the same WLC in Flex mode , both the APs are able to work as per their own regulatory domain channels and max power. with no issues.

3. My assumption is that the same behavior will be seen if the APs are in local mode. But that kind of a deployment is kind of absurd. APs of different regulatory domain on the same WLC in local mode. :) 

4. The point is "how do u know that the power the AP is operating on is not the max power that the regulatory domain allows" ?

Answer: The deciding factors will be : regulatory domain , HT/VHT mode , 20/40/80 MHz , number of antennas . Cisco has recently started providing the excel sheets for "channel and power settings for AP" . You can download this for your AP in use and verify the max allowed power.

Hope this helps.

Cheers,

Manish

[fb_webuser · Accepted solution]

As far as I remember, every AP with a different country code have different permissible level of power and a regulatory authority board monitors these. So in case you wanna mix the AP with different codes, it will choose the ones with lower power level and operate which might not be to your advantage since the users might want to operate at higher power level. So, you can find out the permissible level of Transmission power and group AP with same level together and get another WLC. Also, run a site survey to check for interference. Might help

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Posted by WebUser Shalini Menon from Cisco Support Community App

[Stefan Engel]

Thanks for your comments.

Looks like our current design is not best practice and by having a WLC by country 'should' improve stability/performance.

To summarize:

• having multiple country codes on a single WLC is not a recommended design
• only common channel's (lowest common setting) available
  • Question:
  • --> on 2.4GHz..all our AP's use 1,6,11..this wont change, even I'd have just a single country code configured?
  • so what would change with having a WLC/country?
• power level assignment is not ideal --> most common use

Thanks,

Stefan

[Leo Laohoo]

on 2.4GHz..all our AP's use 1,6,11..this wont change, even I'd have just a single country code configured?

Some countries support 14 channels.  But since one of your APs won't support this channel, then this is the lowest common denominator.

[Stefan Engel]

Got it..thanks for clarify Leo