VWLc issues in a single site

[nhedhili]

Hello 

We have a customer, having one single site with one virtual wireless controller installed on a VM and 200 acesss points located in the Same site and connected to a single vlan ( Vlan 60 ).

the customer is facing multiple performance problems when connecting to internet.

please I need your help , to clarifying some ideas from your experience.

I know that virtual controller supports only flex connect , and I have read in the documentation that flex connect is dedicated to remote branch offices only with some limitations like 50 AP per Brahe office , but in our case we have only one VWLc with 200 access points , is this scenario accepted ? does this affect the performance ? 
do you recommand is to use local switching with groups To avoid the limitation of 500 Mbps performance limitation per virtual controller ?
Is it possible to exceed the 50 AP recommandations on a single site by using the groups or there is another ideas to avoid these limitations ?
thank you for your help and assistance 

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P recommmandations that I have seen in the documentations 

[balaji.bandi]

There are a couple of things you need to Look at.

here is the good document for vWLC 

https://community.cisco.com/t5/wireless-mobility-documents/cisco-virtual-wireless-controller-vwlc-release-7-3/ta-p/3123574

1.  you have given information 200 AP on the site?

2. how many clients?

3. do you have any only issue with the internet ? how about Local Lan connectivity?

4. what kind of internet pipe you have? 

5. do you have any NMS which can give you utilization of the ports - where internet-connected, where ESXi connected?

6. there is may factor you need to consider when you have this kind of issue.

7. is this issue only peak hours, how about non-peak of working hours? (in the night ?)

[Scott Fella]

Lets first review some data… The design to use a vWLC for a site with 200 ap’s rather than an appliance was a poor decision. Now before pointing the blame that its the vWLC issue, what have been done to identify this? What does an iperf test show from wireless to wired? What are some of the complaints the users are saying the notice? Are you able to reproduce the issue(s). When did the issue start happening and was there a change? Can you relate the issue to a particular radio band (2.4 vs 5ghx), SSID, device, OS and or Nic driver version? Does the VM met the requirements stated in the Cisco guide? Was there a site survey done initially? Is wireless design for density or pretty sparse?

[nhedhili]

Thank you for your replies,
1-the access points are a mixture between 1041 and 702.

2- thé L’an design is the following :

two central 3850 12S layer 3 switches Wich are connected to the cabinets on the different floors  via fiber optic 1Giga link , each cabinet contain One 2960S 48 ports with POE Connected to one central switch 
each 3850 has a DHCP server configuration, the firewall is connected to both Layer two switches and from the cable connected stations there is no performance

3-each 2969s switch contains from 8 to twelve 1041 LAP

4-we did multiple site surveys and the coverage is good

5-the VWLC is installed with respect to the installation guide requirements and recommandation 

thank you for your help and assistance 

[nhedhili]

We have only one ssid and one clan for the WiFi , we have about 1500 to 2000 clients , the frequency used is the same 2,4 GHz for all the AP which are composed for 195 AP 1041n and 5 AP 702

the performance problème is not observed on the PC connected to the switches by cables 

we have an NMS and the results show that the is no bottleneck on the fiber links of each 3850 L3 switch 

[patoberli]

The 1041n AP is very old and regarding todays standards very slow.
Have you enabled the newer 802.11n data rates?
Are you using WPA2 AES (or Enterprise) and no WPA1 and no TKIP? This is important for the speed.
If you don't have any legacy 802.11b clients, disable the data rates < 12 Mbit/s for both, 2.4 and 5 GHz. Set the mandatory data rate to 18 Mbps, all other rates to supported.
Also have a look at this document, mostly the linked chapter: https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-1250-series/design_guide_c07-693245.html#_Toc309331104

[nhedhili]

Thank you for your reply , I will apply these recommandations and let you know next  week , because I need to travel in the ustomer site.

in the meanwhile please can you help me to clarify some ideas from design purpose :

1- since the vwlc supports only flexconnect , in this case if we configure the local switching mode than the data traffic will not gi through the controller ? is it the case ? 

2- if data traffic will not go through the firewall, do we will overcome the limitation of 500 Mbps per vwlc controller ?

3 -really we are on the same site and we are using 200 access points with approximately 1500 clients , is this supported oon the Vwlc and  are there any recommandations or optimzations.

thanks and regards 

[Scott Fella]

Local switching dumps the user traffic onto the adjacent connected switch. So the backplane throughput is not an issue. As far as how many clients and AP’s, that depends on your install type and how many license you have purchased. Your design should keep the AP’s in the same FlexConnect group for areas or floor, I think max is 50. For example floor 1-3 on group 1, floor 4-6 on group 2 etc. you don’t have to have exactly 50 access points, just figure out how to split them into groups with the understanding that roaming will break between groups.

[patoberli]

1. You want to do local switching, that way the vWLC has much less to work and you have higher wlan performance.
2. Probably yes, as the client traffic doesn't go through the WLC (if I'm not mistaken)
3. see Scotts answer