Too many meraki AP's?

Meraki-Fan
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Too many meraki AP's?

Our office space is approximately 4000 Sq..  It's an open space with conference rooms made of glass walls and doors.  We recently had a vendor do a RF test to determine how many AP's and location for installation.  They are recommending 8 total AP's.  He is recommending 3 AP's within 15 feet from each other.  It was my understanding that having too many AP's too close from each other was actually a bad thing.  Any assistance with this is greatly appreciated.  Thank you.

7 REPLIES 7
VascoFCosta
Getting noticed

Seems a bit too much for that type of deployment.
What are the network and coverage requirements? How many users and which type of users?


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Vasco
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Adam
Kind of a big deal

I agree with @VascoFCosta.  The Meraki AP's get good range.  Unless you have a super dense environment with a ton of user or if you have a lot of inner walls blocking signal I bet you'd be fine with 3-4.  Are you wanting to have coverage outside the building or just inside?

Adam R MS | CISSP, CISM, VCP, MCITP, CCNP, ITILv3, CMNO
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Did the vendor provide a site survey report which included 2.4 Ghz and 5.0 Ghz heat maps? Those should have been included with their proposal, or at least reviewed with you to support their AP recommendations.

PhilipDAth
Kind of a big deal
Kind of a big deal

Under "Wireless/Radio Settings" enable the option to automatically reduce the transmit power.

 

Screenshot from 2018-02-10 05-10-27.png

jdsilva
Kind of a big deal

Number of AP's can be determined by a few things. If you're going for high density or wireless VoIP you may see more AP's/sqft than a low density deployment. It's OK to have them closer together as long as power and channels are managed correctly.

 

Of course, if you're office isn't a high density area then it may very well be over engineered. Ask to look at the survey and see what signal strength they designed for (they did do a survey, yes?). That might help answer why so many AP's. 

Uberseehandel
Kind of a big deal


@Meraki-Fan wrote:

Our office space is approximately 4000 Sq..  It's an open space with conference rooms made of glass walls and doors.  We recently had a vendor do a RF test to determine how many AP's and location for installation.  They are recommending 8 total AP's.  He is recommending 3 AP's within 15 feet from each other.  It was my understanding that having too many AP's too close from each other was actually a bad thing.  Any assistance with this is greatly appreciated.  Thank you.


There are a great many variables that come into play when designing a Wi-Fi system.

Don't Guess - Measure

Use a site survey tool such as one of those provided by Ekahau. They have a range of products, even a free version - HeatMapper

Guestimates off the plans are just that, and walk rounds without measuring are little better.

Recently built or refurbished spaces can provide interesting problems, such as foil backed plaster board. This sort of issue usually doesn't make itself known until installation and set up, without a site survey. Construction and refurb jobs rarely end up being exactly as specified. Walls that look similar but originally divided different tenants can turn out to have quite different characteristics as far as RF transmission is concerned, because of fire regulations.

Don't Chase Range

From a practical usability, flexibility and management point of view, it is preferable to have more smaller, cheaper APs operating at the lowest RX volumes commensurate with adequate signal coverage, than to have fewer larger units operating at high RX volumes.

As a general rule of thumb, I plan on providing at least one AP for each space that needs WiFi access. Put APs in rooms, not in corridors.

The 5 GHz signal has half the propensity to leak into adjoining spaces as the 2.4 GHz signal. But it is twice as reflective. In some urban areas the interference from Wi-Fi users in nearby spaces, cordless door bells, microwave ovens, bluetooth devices, and faulty electrical equipment can make it best to avoid the 2.4 GHz band. This band, in practice only has 3 non-overlapping 20 Mhz channels, so there is usually a great deal of contention for free channel space.

At the moment, 5 G Hz has certain advantages, including more non-overlapping channels, higher potential throughput, and, in the case of 802.11ac, more secure encryption, than alternatives available on the 2.4 GHz band.

 

Hard Wire All Immobile Devices

Wi-Fi is not a boundless resource. It is scarce. Do not exacerbate this issue by using wireless to connect devices that logically should be wired.

 

I look forward to hearing how the site survey goes. (And I haven't even mentioned DFS, TPC and CAC, yet).

Robin St.Clair | Principal, Caithness Analytics | @uberseehandel
MerakiDave
Meraki Employee
Meraki Employee

A lot of good pointers in all the replies.  And I'd agree I cannot think of a time when I'd have 3 APs within 15 feet of one another in a relatively open space or 8 APs for a 4,000 square foot relatively open area of conference rooms.

 

The vendor who did the RF test, did they conduct an actual RF Site Survey of the 4000 square foot space?  Are there 8 conference rooms and they simply defaulted to an AP-per-room?  Regardless of the situation, the answer to "how many APs do I need" is ALWAYS "it depends" on multiple variables and figures of merit.  If they just said they wanted to do an AP per conference room, or in your case perhaps an AP per 500 square feet, you may be sorely disappointed with the deployment. 

 

Like in home construction an important figure of merit is span, the distance between support columns, and are you measuring that under dead load or live load for example when measuring how long a joist needs to be.  And are you considering the type of flooring to be used or how much deflection is within acceptable limits, etc.  The point is it's a complex composite of many variables.

 

In wifi there are a few critical figures of merit, and one of the most critical is duty cycle (channel utilization).  So the answer to all other wifi design questions is "it depends" and  hinges on what is going to drive the channel utilization.  The point is that it’s a half-duplex shared medium, channel utilization is a critical figure of merit, and voice (for example) has a dramatic impact on channel utilization.  You must also consider the capabilities of the client devices (or at least a likely mix of client devices) so you can get an idea of airtime consumption.

 

This approach will tend to raise all the natural questions about what applications must be supported, what protocols are being used and what the application traffic footprints look like, what are the capabilities of the clients with regards to channel width and spatial streams, etc.  And only then can you start designing a plan for AP placement and a 5GHz channel plan.

 

Once you come to an estimate of airtime consumption you can estimate the number of APs required to serve a given number of devices over a certain area.  Here's a little more info on doing a quick & simple estimate in this other post https://community.meraki.com/t5/Wireless-LAN/Maximum-number-of-clients-on-MR84-access-point/td-p/478...

 

All that said, there can be exceptions.  In your case, if they recommended 8 APs, maybe for 8 conference rooms, maybe they specified the MR30H as a table-top AP in each conference room?  I've seen library deployments of that nature work well for example, as if each "study/conference group" of 5 to 10 people has a dedicated AP.  Or college dorm rooms and hotel rooms with MR30H where there might be an AP per room and perhaps only 15 to 20 feet apart.

 

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