MR52 Auditorium Deployment

[SFascot]

I have inherited an issue and looking for the fastest, cleanest way to resolve it.  We have an auditorium that seats 821 people.  We have 4 production SSID's.  2 of which are password protected, 2 of which are open with radius mac address authentication.  And we offer a BYOT network.  The previous person that handled the WiFi before me never planned on every person having a device and attempting to use it at the same time in the Auditorium... so they only deployed 2 MR52's in this space (plenty of signal though for the size of the space).

What I noticed first time they went to use it... each MR52 only had roughly 30 to 60 clients out of a guaranteed 700 people with devices.  We took away the BYOT network this year, but it appears there were many personal devices spamming the AP's trying to get an IP.  Most with 0.0.0.0 or 169 self assigned IPs.  And each MR52 only has a single 1 gig copper line to it.  Many of the production device chromebooks weren't even getting an IP address at all, and I believe those personal devices trying to get on our production network were the cause.

We have spare older MR2x series, a few MR3x series... but I don't believe just hanging more AP's will magically fix this area since it is open space and the 2.4 channels will overlap.  I also believe the personal devices were spamming the AP's trying to get an IP and locking them up as the AP wouldn't pass traffic even if you did get an IP address.

I thought of creating a new radio profile just for the auditoriums, so I could hang more AP's and just disable 2.4 radio on all of them since all of our issued devices are 5.0ghz capable.  But from researching the forums and documentation, I believe we would need roughly 8 access points total and I still couldn't guarantee a decent experience in the space.

Can someone else who may have set up an open space share how they would overcome this issue?

[cmr]

You'll need a lot more APs to properly service that number of users, I'd suggest about 15.  You'll also see that the auditorium profile in the dashboard turns down the radio power to limit the issues caused by frequency overlap.  This also restricts the number of devices that can talk to each AP.

We cover casino floors like this and we also set our device SSIDs to 5GHz and the public ones to 2.4Ghz.

[NolanHerring · Accepted solution]

Not sure what the T in BYOT stands for (am I the only one?)

As for your issue, if you need to support 700 devices, then you need to do the math to achieve this. You need to know what the device types are going to be. Once you have the math part figured out, then you need to design the wireless to try and make the math actually work from an RF perspective.

The math part can be figured out roughly via the following: http://www.revolutionwifi.net/capacity-planner

I can't fill that part out for you since only you will know what your going to have to support. Off the cuff, depending on what type of traffic/application/devices being used, it could range anywhere from 6 access points to 12 (maybe more?). I'm not saying you need 12, but depending on what your trying to do you might is the issue.  Are all 700 devices actively and concurrently using the wireless at the same time etc.

This will be difficult to achieve if all you have is an open auditorium with just internal model access points along the wall. Even if you had 10, there isn't any real way to control which AP the clients will connect to. An AP might have 150 clients, and the other might only have 30.

This can be achieved by using directional antenna, power, channel assignments, and possibly some RX-SOP to 'force' clients to connect to the AP they should be (this will break your roaming, but for auditoriums this may not matter since people are sitting in seats using the devices [assumption].

You need to go out of your way to ensure that there is channel re-use, basically meaning that no two access points are using the same channel. I would plan for 5GHz only, but if you have to use 2.4 then make sure you only have it enabled on three access points. Unless of course there is a coverage issue then, you'd rather have coverage with contention than no contention and coverage issues.

If this is something that you inherited you might want to look at hiring a 3rd party company that specializes in this. There is a lot that can go wrong if you don't know what you are doing, and if your the one that is responsible for the success of this then you might want some insurance 😃

[PhilipDAth]

@NolanHerring has a lot of experience in these areas so pay heed.

I think you are going to need to spend a lot of money to put this right.  I suspect you will have high roofs, and will need to use a "spotlight" antenna like this:

https://meraki.cisco.com/products/wireless/antennas#MA-ANT-3-F5

These antennas light up a small patch like a spotlight, so you can re-use the channels across a venue.  The downside is you are going to need to use MR53Es for these.

But you are going to need to alot more MR's anyway.  I think @NolanHerring 's guess might be a bit lite.  I would be running with at least 14 APs (50 devices per AP - ok performance) to 28 APs (25 devices per AP - excellent performance).

Also note that if you do the above you can look at using the "Auditorium" RF profile.

https://documentation.meraki.com/MR/Radio_Settings/RF_Profiles

Also for your "own" networks I would try and use 5Ghz only.  Turn off 2.4Ghz on SSIDs that don't it.

ps. I have run into wireless mics and wireless video repeaters that operatored on 2.4Ghz - so watch out for that.

ps. I don't know what BYOT is.

[SFascot]

BYOT - Bring Your Own Technology.  Cell phones / tablets / personal computers.  Anything that needs internet that isn't provided by us.

I do have high roofs, and the only APs we currently have are internal antenna models.  My meeting with my boss is tomorrow afternoon on how we can change things, and I do believe my best bet is to recommend bringing in an outside company that can do an RF Spectrum analysis and actually guarantee a working environment that will play nice with the APs in the rooms nearby.

[BlakeRichardson]

@SFascot If you can do so disable 2.4Ghz, we did this site wide and it solved a large amount of problems.

Secondly How large is the space you are talking about roughly, we have a similar sized space that seats aroudn the same amount of people although we use a different wireless vendor. My plan for 2021 is to deploy wifi 6 into this space with the switch gear to support it.

Are the current access points well place and either mounted vertically or horizontally and not on some wierd angle?

Supporting that meant clients will mean a large amount of hardware and in a small space you are very likely to run into pollution and noise issues if you are not careful. 

[cmr]

@SFascot make sure any spectrum analysis and WiFi survey is carried out with as close to normal occupancy levels.  We found hundreds of people with all their personal hotspots (mainly from iPhones), unsurprisingly, make a big difference to how the APs work!

In the end we set up as per a survey and then looked at how the APs behaved using the tools in the dashboard, we have added about 50% more APs in key locations between busy APs and are nearly there for most of our auditorium style spaces.

[SFascot]

@cmr we haven't had a spectrum analysis done at all yet, I do keep pushing for one.  But we do have an MR42 in every classroom, and I worked very hard last summer to fix a lot of channel, power, and usability issues.  We were sold the MR52's for our high density larger areas like gyms, auditoriums, cafeterias by a vendor and my predecessor.  I have 2 MR52 AP's in an area trying to supporting 700, and another building only has 4 MR52's trying to support 2100.  My classrooms run very smoothly.... but these high density, open areas are going to be disaster zones.  The worst one is the one in my scenario as I only have 2 copper network cords going into that space.  The AP's are mounted on the walls.  One on the front right corner, and one in the back left corner.  I think they were planned to give basic wifi coverage for presenters.... but the space is being used differently now that every kid has a device given out by us.

[cmr]

@SFascotoh my, that is slightly under provisioned!  You could put a PoE switch in the location and run cables locally I guess as one was or another you are going to need a significant number of additional APs...

[SFascot]

@cmr I think what @NolanHerring recommended with having an outside company come in will be my best bet.  I believe we will need to run a new fiber from our MDF to each high density area (Auditoriums, Gyms that host events, and our Cafe/Stage/Gym combos)... then create an IDF locally there dedicated to access points.  Going to have to treat these like their own separate mini networks.  Thanks everyone for all the assistance.

[Bossnine]

As was said, and also how much do you really want to support. I have roughly 900 seat auditorium (2 stories) that I have to support in the school system I work for but its not a priority room, meaning if we can reasonably support guests then its fine.  If 900 people crowd the room and they all have at least one device and they want to stream a 4k video, well we just simple don't feel it necessary to support that.

I have 5 access points in there, 3 serving the bottom floor and 2 serving the top floor.  No, it would not support everyone all the time but it adequately handles what is mostly in there.........which is an occasional event with a percentage of people on their phones playing on facebook on my guest account.

We did have a teacher event one time where we had a large crowd full of tech savvy teachers showing off their new tech toys (and I have pic to show this) and they complained about some 'slowness', but they all managed to do what they needed.