A Wireless Challenge

[jtpntx]

I work for a large school district and I have recently accepted the position as Wifi manager and I have a lot of work to do.

The good, the bad and the ugly.

Good: Everything is new. Core, Distribution and Access all new deployment. 9800 WLC, New AP deployment 9120,9130 and 9166 at every campus. Recently launched DNAC and currently transitioning from Prime.

Bad: I'm solo and I have few resources as of yet. “They” decided not to migrate from Prime so I have to build DNAC wireless maps for 70+ campuses/over 4000 APs.

The Ugly: None of the Campus Wireless Networks were designed properly. Its a 1 AP per classroom design and a lot of hallway APs also.

Even before the recent equipment upgrade the network performed okay. However in the last few years with student 1 to 1 devices problems have begun as expected. Especially with Elementary campuses. Old buildings and IPADs. Middle school and High School use Chromebooks. You might say they have less problems than IPADs but there are too many factors to discuss.

Now I must say that with the campus construction and layout especially in the older buildings the 1 AP per Classroom approach on 5Ghz isn’t completely off the rails but again there are too many IPAD issues and that is going to be my focus initially.

As soon as DNAC is fully functional I’m hoping it lives up to the hype in terms of diagnostic info, monitoring and remedy.

I also believe that I desperately need to begin validation surveys and spectrum analysis. It appears a good option would be Ekahau AI Pro using a Sidekick 2.

I welcome any and all advice.

[balaji.bandi]

Personally to get optional outcome of Wireless (you need site survey with professional level)

Good to have Local equiment to be in place to ongoing survey done when you have issue.

For intial setup these kind of deployment always hire professional services to validate the desing and deploy for you and move transtion for you to maintain.

DNAC and Prime can be in the same estate until full confident and Migrade to DNAC.

Make sure you need to consider what kind of end device stundents used.

[No Cables on Me]

Take it slow.. dont try to fix everything at one.. 

DNA-C is not all it cracked up to be, and before people jump on.. there was a told call Cisco Works and another OPenView ( dated myself).

Survey budget can be a beast specially for public institutions, since you mention SideKick sound like you have some experience..  Prob too late to do APOS, but you can do your own validation.. 

Start with a configuration review, use the analyzer tool.. make sure you doing as much best practice. 

[ammahend]

You can import everything from prime into dnac and add only additional, you don't have to build everything again in DNAC.  

Seems like you have sufficient APs, to start with run the basic KPI check on wireless intra. Things you can do for free. 

 https://cway.cisco.com/wireless-config-analyzer/

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/217738-monitor-catalyst-9800-kpis-key-performa.html

can you elaborate on endpoint issues you are seeing with ipads and chromebooks ?

[jtpntx]

I haven't found yet where I can only migrate/import the maps. 

Regarding the endpoint issues. MacBook, Chromebook and Win10 issues aren't consistent. What is consistent is IPADs dropping connection or not acquiring connection. You get the spinning wheel as they call it until "no internet".
A very common method teachers and students use is to walk to another location in the building usually a known sweet spot. Could be a hallway or caferteria. It varys. Once you have connection the student can return to the class room and usually will be fine for a while at least.
Often times this happens when there is 15-20 students in a group.
At 1st it makes no sense. I don't see overlapping channels. It is not an infastrucure issue. 
This problem seems to be more common in what we call "H" Buildings. Two long parrell halways with a connector hallway.
In these building it is usually and consistently at the end of the halls.
I don't believe the students are taking the IPAD "To" something to get a signal. They are getting away "FROM" something and I haven't figured it out yet.
Co-Channel interfenence isn't it. Adjacent Channel interference...Maybe but it isn't obvious.

I think that leaving the Channel selecition up to DCA and the power setting left in "Global" is not working. The reason I mention that is there are those who will object to having to manually and selectively configure every AP. 
It isn't what has been done in the past and I say that actually my point. 

[jtpntx]

Definately looking into it having a pro come in. At least on a couple of campuses to start off.

[jtpntx]

Couple of examples

[jtpntx]

[jtpntx]

clearly a lot of ACI and some co-channel.
It will be a task to tweek DCA/RRM to handle this. Im think at least at the Elementrys it's going to be manual config.
IPADS do not play well in this enviorment.

[jtpntx]

Turns out, the problem that has rendered this wireless network unstable for longer than anyone wants to admit is Load Balanace enabled. At least to the extent that I turned it off and the problem goes away.
It appears that IPADS are the canary in the coal mine. They getting impacted 1st or have less ability to recover when wifi issues are encounterd.
Followed by Iphones, Macbooks, Chromebook and finally Windows. In that order so it seems. Nothing documented here.
The problem was IPADs loosing connection or not connecting at all. Totally random but consistent. Students would have to relocate to acquire a signal then return to class. External APs in close proximity seem to be common

Using packet capture I got a ton of association denials. 17 STA MAX. which indicates the AP is saying max connections.
I turned off load balance (thanks to a reddit post) and it all went away. 

Acutally I've turned load balance off on the backup 8500 WLC and have been moving APs to it a few campuses at a time. I am now convinced and ready to disable it on the main controller.

Chromebooks get the same association deinals but they recover rather than just stalling out. Recently we deployed the latest DELL student model and it seems to be affected more so than the previous CBs.
So it is not and IPAD problem necessarilly. Depends on how you look at it.

So maybe there is a way to implement load balance correctly but as it stands teachers are able to do their jobs without it.

[Rasika Nayanajith]

I would use WLC config Analyzer (WCAE - 9800 & WLCCA - AireOS) and get a bigger picture assessment. Then if 9800 AP migration already in place, then do that and only focus on 9800 to address the issues highlighted in WCAE. Refer below post for more guidance
https://mrncciew.com/2022/08/12/cisco-wlc-config-analyzer/ 

RF issues has to fix in that level and no controller setting can fixed it permanently. If you are using 6GHz (9166), then Ekahau SK2 is the tool to go for as of today. Having it inhouse make more sense as you can look into spectrum, validation surveys as need basis.

HTH
Rasika
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