WLC 2504 throughput

[Ruslan Moldaliev]

hi folks,

I have an very simple question but still can't find the answer:

we have a couple of them at the office and I want to see whether it's time to upgrade or time to troubleshoot network speed issues. how can I see/check current throughput on the WLC 2504?

I know I can see switch port load, I'm rather interested in native throughput counter.

thanks in advance!

[Scott Fella]

That is tough... Typically you can look at the switchport utilization of the issue is with the controller and being over utilized.  First off, I would not start at this. Define what the issue is being reported, is it everyone or a selected few, was there a change in code or anything on the network side?  I really doubt that it can be the controller. Usually is client side, configuration issue or network issue.  So you need to determine what it is by process of elimination. 

-Scott

[Ruslan Moldaliev]

do you mean ports utilization of the switch where WLC is connected under "..switchport utilization of the issue..."?

currently it's issues with WiFi quality mainly with MacBook Pro and I'm trying to exclude different factors that can influence. I know it's very popular "feature" of Apple products:).

Also user and AP population is constantly growing and I would like to predict when we will hit the throughput ceiling.

[Scott Fella]

With Apple devices, its best to make sure you only use one type of encryption.  You should use WPA2/AES and not have WPA/TKIP also enabled.  Apple devices have issues connecting with a mix encryption.

-Scott

[Ruslan Moldaliev]

thanks for the suggestion, I have this setting enabled already. maybe you have a couple other related tips? I would appreciate it, those Apple devices are driving me crazy.

do I understand you correctly that there is no possibility to see current throughput level at the WLC itself?

[Scott Fella]

You can try to look at the monitor tab and then ports to see some statistics. The fact that your mentioning issues with Apple devices and not all devices, means your code or configuration is the issue. Post your show WLAN <WLAN ID> for the SSID that Apple devices use. Explain to me some of the things end users complain about. 

-Scott

[Ruslan Moldaliev]

I'm sorry for the delay in answer. here in the attachment output of "show wlan X".

and usual issues are:

- long connecting time to the WLAN, not less then 1-2 minutes, sometimes turn off/on WiFi connection helps do it faster.

- random disconnections from WLAN, sometimes with long reconnection time.

[Scott Fella]

Disable client load balancing.  Also when you are having these issues, how many devices are associated to a given AP?

-Scott

[Ruslan Moldaliev]

client load balancing option has no matter, I tried on/off and no difference. after this information does it still need to turn off?

in average from 10 to 20, sometimes more, not optimal AP location is related with a little bit chaotically growth of company, AP location points was considered manually at that time.

[Scott Fella]

Load balancing should be turned off. This causes issue with clients connecting when you start hitting around 10 devices on an AP. Devices will take a long time to connect and some will not connect. Others that are already connected might drop off.  Also if your using 40mhz channel width, set that to 20mhz as some wireless NICs have issues with 40mhz.

-Scott

[Ruslan Moldaliev]

have you used this recommendation in the production environment? is it mainly used for backward compatibility with older devices? and am I thinking right that max data rate will be 72.2 mbit/s? information from here:

https://en.wikipedia.org/wiki/IEEE_802.11n-2009#Data_rates

also I wanted to ask if using FlexConnect with Local Switching will decrease throughput load on the controller?

thanks, I'll try to test your recommendations ASAP.

[Scott Fella]

Yes, that is our standard when we deploy. FlexConnect local switching might help or not. You just need to make sure you understand the limits of FlexConnect because it doesn't do everything local mode does. Cisco did a study recently and also mentioned that they have not seen throughout max even close to a gigabit. The issue your seeing can be because of client side issues.  Since wireless is half duplex, if you connect at 72mbps, the expected throughout is half of that with one device. Wireless is a shared media so the more devices the less throughput one has. It's like a wired hub.  

Mad far as client load balancing, that has caused issue for a very long time device manufactures that don't support status code 17 (what Cisco uses to try to load balance), have issue with this enabled.  

-Scott

[Ruslan Moldaliev]

I'm sorry, I lost part of sentence in this one: "is it mainly used for backward compatibility with older devices?". I meant: "20 mhz channel width, is it mainly used for backward compatibility with older devices?"

and could you give recommendations regarding max clients per AP in case when every user have a couple of wireless devices: notebook and smartphone. from your experience. I know it's not simple question, I would like to hear approximate numbers.

PS. for 2602i and 2702i AP and WLC2504. and whether own user's smartphone is count for "full" client.

[Scott Fella]

No.  The issue with 40 MHz is that some clients drivers are affected and causes client side issues. My rule of thumb that has worked for me is 30 or less devices on an AP.

-Scott

[Ruslan Moldaliev]

we moved to new office and I finally had a chance to implement your recommendations - turned off client balancing and set 20 Mhz wide channel. so far seems okay, but anyway better then earlier.

thanks