Large denisty of APs use-case and lack of auto channel selection

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Large denisty of APs use-case and lack of auto channel selection

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Large denisty of APs use-case and lack of auto channel selection
Large denisty of APs use-case and lack of auto channel selection
2020-06-16 19:04:13
Model: EAP245  
Hardware Version: V3
Firmware Version:

Hello everyone,

 

We are planning for a large deployment of EAPs wherein one building alone can have 200 APs. Unlike Ubiquiti, where we have WiFi - AI that has been working beautifully to auto adjust the channels and exclude DFS channels, how do you deal with lack of a proper auto channel tuning feature with periodic scan of the environment for large deployment?

 

Anyone with 50 or more APs inside one building, can you please share your experience?

 

Thanks

 

 

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#1
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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-17 16:02:26

Hi @dpsguard,

 

You'll just have to set them manually in a honeycomb / alternating configuration.  There's no need to change the channels after everything is all set up.  Wifi penetration (outside of building in / inside of building out) is generally pretty negligable with modern energy efficiency materials (e.g. IR coated glass, metal / masonary skins)

 

You'll probably want to use all 20MHz channels for both 2.4GHz and 5.8GHz in this high AP density / high STA environment.  EAP225 & 245 do not support DFS (in the USA) so that won't be a concern.

 

Based on your floor layouts and AP spacing, you'll lower the AP transmit power to ~14 or 16 dBm and try to layout your AP placements to eliminate / minimize channel overlap using channels 1,6, and 11.  5GHz will be much easier with 20MHz channels as there are 8 to choose from (or 4 40MHz channels).

 

In Europe where channel 13 is available, some folks advocate a 4 channel 2.4GHz plan, 1, 5, 9, 13.

 

How many STA's per floor?  What types of applications will they be using?  Is all Wifi, or will PC's / phones have Ethernet?

 

All of our corporate Cisco deployments use fixed channel and power assignements based on Pre and Post AirMagnet surveys.

 

-Jonathan

 

 

 

 

 

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-17 16:26:04

Thanks for your detailed response. In a downtown type of sittuation, even a 10 years old building has lots of bleedthru from floor to floor and thru the tinted energy saving glass windows. And you can see lots of 2.4 as expected at relatively high enough level to make life miserable for 2.4 transmissions as virtually all 3 channels are seen in use and this causes lots of waiting turns for clients from activity on other co-channel transmissions from neighbors, so throughput is really low on 2.4, but I am not worried about that, other than that iphones somehow like to prefer 2.4 even with bandsteering, low powers, disabling low basic rates and even rx-SOP etc.

 

The use case is college application. I believe you meant to say that when doing manual allocation of channels, DFS wont be available and that is true by design for all Wi-Fi business radios. But that is also a loss as we cannot use those channels if we allocate manual channels. In high density use case, we want to deploy as many channels as possible. And then you are under pressure to deliver more bandwidth and hence wider channels, than is really needed and useful, but do you have some data on 20MHz / 5GHz channel deployment as to how much Iperf or even speedtest results we can get on a modern laptop? 20MHz should allow over 200Mbps connection rate for laptops in close proximity and 90 to 140Mbps of actual throughput, if I recall testing with a school setup utlizing Aruba IAP2xx series APs (and school had an AP per classroom with high desnisty of classroom on two floors and a basement (private school). and we had it set to auto channel selection (Aruba Instant does pretty good job and at very deep discounts to education sector, it was not expensive) and at least for 2 months after launch that I was still in communication with IT group, they had only good things to say and no reports of any slowdowns. And I belive we had 40MHz channels on 5GHz. Powre level of course was set to 10dBm on each 5Ghz radio and 4 or 5dBm for 2.4 radios and even then 50% of 2.4 radios were alos turned off. Schools have lots of old ipads and chromebooks and likewise that support 2.4Ghz.

 

Are 40MHz channels on 5GHz work satisfcatorily in any of the EAP245 deployments with 50APs or more inside any building?

 

Thanks again.

 

 

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-17 16:56:51

Hi @dpsguard,

 

What I meant was that the EAP225 and EAP245 are not approved to use by the FCC / do not support DFS channel frequencies in the United States -- irrespective of how channels are assigned.  I'm not sure which country you are in.  The TP-Link EAPs do support some DFS channels in some countries (e.g. EU).

 

Other vendor hardware, like the Cisco's we use at work, here in the USA, do support DFS channels.  But, it's kind of hit or miss whether the Network Deployment team decides to use them or not.  Some vendors do, so don't.  Pretty much all 5.8GHz capable clients support DFS these days.

 

At work we use the Cisco AIR-CAP2702I-B-K9 which is a 3x4 spatial stream product.  I forget exactly whether this is 3 UL and 4 DL, or 3 for 2.4GHz and 4 for 5.8GHz.  Anyway, out laptops are 2x2.  We use all 20MHz channels 2.4GHz and 5.8GHz.  I am actually just an end user here.

 

I get roughly ~115-120 Mbit/sec of sustained,  5.8GHz 20MHz 2x2 wifi throughput from these AP's to my Lenovo T480 SSD laptop.  Although this is slower than I get at home on my personal Wifi (TP-Link 225V3 80MHz 2x2 w/FIOS Gigabit) -- roughly 350-450 Mbt.  In reality, it is plenty fast for everything I need to do at work.

 

Thank you for the background on the project.  What will the STA's be doing / what types of network applications will they be using?  Is this a dorm, a technology classroom, labs and offices, etc?

 

Is everyone streaming YouTube/Netflex/Pandora and Zoom all day, while trying to FaceTime, VoIP/Wifi-Calling, and share files Peer-to-Peer?  The EAP245 might have slightly better user capacity if the MU-MIMO is working.  But the 225V3's are much cheaper (slightly more than half the price) and far more commonly deployed.

 

If it were me, and there was a lot of 2.4GHz interference, I would offer 3 SSID's -- one for 2.4, one for 5.8, and one for Band Steering.  Not all clients support Bend Steering well, and it's nice to be able to choose 5.8GHz only.

 

Depending on your AP layout, 40MHz on 5.8GHz could be an option.  BUT, the real question is will you be throttling individual STA's anyway to a certain DL/UL BW so that everyone "plays nice?"  If so, having wider BW channels is not really helpful / necessary -- you would be better served by having more / higher density AP's  -- assuming you are expecting a lot of ST's.  Sometimes folks will even have 5.8GHz only AP's mixed in to support extra high density / higher BW applications -- if you have enough channels available.

 

I actually use channels 3 & 9 at home, instead of 1,6, and 11 -- as these are heavily used by my neighbors.  But their signals are fairly week, and in general, this is not a recommended practice.  Defiately Pre-Survey and mark external interference and try to limit your channel plan near the periphery of the builiding where neighbor interference is observed -- if it's stronger than -75 dBm or so.

 

-Jonathan

 

 

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-19 18:35:33

@JSchnee21 

 

Hi Jonahan,

 

Sorry for lae response. I was working out of town.

 

Yes we are talking about US and it is for private school where you have the school and dorms all in one campus. Interesting to note that we cannot use DFS channels in the EAp proiducts in North America. So definitely not a good idea to use 40MHz anyway.

 

My own tests indicate at home that if I set up my Aruba AP to 20MHz, I do get close to 135Mbps (using Iperf from my wifi connected laptop to my pfsense firewall based iperf client / server). if I change it to 40MHz, then I get 220Mbps or somewhere around that. If I set it to go up to 80MHz, then I can easily get 550Mbps. There is a need to deliver ( at least when kids do a speedtest) they get close to 100Mbps, but what happens if you have 40 dorm apartments on 4 floors with 200 studnets in them and we put in a EAp245 in each apartment, I am sure, with 20MHz channel width set, we can get closer to 100Mbps. Average load generated based on my experirnce is liek 1Mbps per student at busy night time of 9:30. This does assume that some might be still not in the dorm, some may be sleeping, some not using the internet, but if I take 1Mbps per student, that works very well to decide on overall internet sevice needs.

 

And i will assume that there will be lots of traffic utilizing Google Meet for online class sessions this coming school year, plus add usual Netflix and Youtube, so deciding on EAP245v3. With an AP in each apartment, pre install survey work is eliminated. No idea how well the MU-MIMO has been tested in the EAP245s, but if that works, it will help better experirnce by supporting multiple devices at the same time.

 

And finally yes, we only do two separate SSID, one for 2.4 and one for 5GHz to resolve iphone sticking to 2.4 most of the time issues. And the staff SSID is combined 2.4/5 with band steering and basic rates set to 24 for 2.4 and 36 for 5GHz and no speed caps.

 

Thanks so much for sharing your experience and stay healthy and blessed.

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-20 22:38:38

Hi @dpsguard,

 

Thanks for the info.  Sounds good.  I would still go with the EAP225's IMHO, they still have 3x3 2.4GHz radios (same as the 245) and are 60% of the price of the 245's.  Of course they only have 2x2 5.8GHz radios (vs. 3x3 in the 245), but TP-Link also seems to update the 225 software more frequently -- it's a much more popular product.  I run 225V3's in my house and have had up to 40-50 Wifi clients on a single EAP without issue.  And that was with many kids streaming and gaming simultaneously.  Since you'll have a limited number of Wifi clients per apartment -- say 20 or less -- the 225's will be fine.

 

If you have ~10 apartments per floor, using the 20MHz 5.8GHz channels would make a lot of sense, IMHO.  Especially if you're looking to limit BW to ~100Mbit/apartament or about 1Gbit/floor anyway.  Most clients these days tend to be 2x2, or occassionally 1x1.  Very few clients, save for rare high end laptops have 3x3 radios.

 

Also, FYI, even though these are omnidirectional, the RF cone is designed for ceiling mount in a central location.  Hopefully the floors/ceilings are concrete so you won't get much RF penetration from floor to floor.

 

You'll need to run a Windows or Linux Server for Omada to handle that many EAP's, the OC-200 tops out around 50 AP's or so.  Unless you put one per building -- which could be an option.  This way you'll have centralized configuration, management, and clients will have fast roaming from AP to AP.

 

If possible, I would still provide hardwire drops at desks and TV/Media center locations.  This way you can offload a lot of hard core streaming and gaming to hardwire and keep this traffic off of Wifi.

 

My frst year at Johns Hopkins, in 1994, we still had asynchronous serial connections in the dorms for remote terminal services (IRIX) sessions.  My second year we got 10 Mbit Ethernet.  When I worked at Walter Reed in 1998-1999, we still used Thinnet e.g. 10Base-2.

 

My how times have changed.

 

-Jonathan

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-20 23:23:31 - last edited 2020-06-20 23:28:13

 

JSchnee21 wrote

Unless you put one per building -- which could be an option.  This way you'll have centralized configuration, management, and clients will have fast roaming from AP to AP.

 

Just for the record: If using separate controllers (one per building), fast roaming will be restricted to EAPs in those buildings only.

 

My frst year at Johns Hopkins, in 1994, we still had asynchronous serial connections in the dorms for remote terminal services (IRIX) sessions.

 

Cool. I worked at SGI back then and still have IRIX running until today. Even my web server runs on IRIX since 25 years now, albeit with up-to-date applications. When downloading Omada Controller community version, you connect to an FTP server running on a SGI Origin 200. :-)

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-20 23:25:36

@JSchnee21 

 

Thanks again Jonathan for your advice.  i need to use EAP245 as that is the only AP that has two ethernet ports. I need a passhru port to plug in a mini switch for wired ports, with AP being on the direct cable and POE from floor network closet. I cannot run the AP thru the mini switch, even if I use POE mini switch as if local power is down or switch is down, then wi-fi will also be down.

 

And I am older than you and I have worked on thicknet and arcnet and of course dialup modems....

 

OC200 is specified to suppprt up to 100 APs and yes, I will have one OC200 per building and then multiple of these can be added to the cloud portal. The link below from 2019 even talks about OC300 supporting up to 500 APs, but I dont find OC300 on website. Maybe they annouced it, but did not launch it yet.

 

https://issuu.com/tplinkde/docs/8392501058_2019__smb_product_guide_english_1905

 

Appreciate again and enjoy your weekend.

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-20 23:39:50 - last edited 2020-06-20 23:40:59

 

dpsguard wrote

but I dont find OC300 on website. Maybe they annouced it, but did not launch it yet.

 

TP-Link Hungary lists OC300 as »Coming soon« and shows pictures of it, but the web site template still has text for OC200:

 

https://www.tp-link.com/hu/business-networking/management-platform/oc300/

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Re:Large denisty of APs use-case and lack of auto channel selection
2020-06-21 03:31:08

Hi @R1D2,

 

"Cool. I worked at SGI back then and still have IRIX running until today. Even my web server runs on IRIX since 25 years now, albeit with up-to-date applications. When downloading Omada Controller community version, you connect to an FTP server running on a SGI Origin 200. :-)"

 

Awesome!  I remember one year, SGI brought a whole semi truck on campus.  It was all decked out with logos and swag.  When you walked into the back of the trailer they had all sorths of workstations setup with 3D goggles to visualize molecular stuctures, various CADD models, etc.  It was really cool stuff back then.  Jurassic Park aside.

 

I personally never did very much with them, pine, talk, FTP, Lynx, etc in college.  It was the bee's knees until NCSA Mosaic and ICQ came out. (-:  At Penn State we had a few IRIX workstations in the Chemistry department.  But by then a lot of the ab initio work was being done on Macintosh / PowerPC's. -- at least for the chemistry computer lab I used to support.  I'm sure the professors has better equipuent.

 

Did a bunch with Solaris and Oracle at work, and some Linux, and of course WIndows.  I still do some IT stuff at work, but not so much any more.

 

-Jonathan

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