Best Practice to Decide Where to Place WAPs in a Large Home

[Len Levin]

I have a business customer that is in the stages of building a new, rather large home.

I have been tasked with planning the WiFi coverage for this home.  My plan is to use WAP150s or equivalent with an appropriate POE switch and a RV series VPN router.  The reason for the VPN router is to create a persistent tunnel to his office.  This is the equipment that is being used in his office and at another smaller home.  I will also have a tunnel form my office for support, etc.  This has been my hardware of choice for many years.

My approach in the past for WiFi deployments has been to eyeball the placement and number of WAPs, assign each WAP a static LAN IP, set the radios up with the same SSID/Password and a different fixed channel.  This has worked well in the past with both good performance and without complaint.

In this case I need to let the electrician know where to place the CAT wire for the WAPs and other devices.  I need to get it right or close to right the first time.

I am interested in how others would approach this task, what tools to use, etc.  I see this as a learning experience.

Thanks.

Len

[Rasika Nayanajith]

Best way to go is using a site survey tool like Ekahau

HTH

Rasika

[Len Levin]

Rasika,

Thanks for the reply.  That is a little out of my price range.  Any other suggestions.

Len

[Haydn Andrews]

If you have access to Cisco Prime you could use its predictive wireless design feature - not as advanced as Ekahau.

You might also be able to get a trial version of some of the survey software and see if you can complete the design within the limitations they normally place on it.

[Leo Laohoo]

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@Len Levin wrote:
That is a little out of my price range. 

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Find someone who can do it right will save you the hassle of retro-fitting because it was done wrong in the first place. 
Currently, the price to retro-fit a faulty WiFi placement costs about 4 times of putting an AP.  
If you get this wrong, that person won't be calling you his "friend".

[tottenavl]

I really like the enterprise site survey tools as well, however given the cost constraints in the scenario I would suggest the following approach. 

Using your intended AP set the power to 14dBm on channel 36 and configure a test ssid.  Then move the AP around to a proposed location and test RSSI with a MacBookPro associated to the test ssid.  Ideally I would suggest a cell edge of at least -67 RSSI.  Make sure your test AP is mounted as it would be in its permanent location.  Even though this approach is not as efficient as with Ekahau, it provides good survey data through the client's perspective!  BTW:  on a Macbook you can reveal the RSSI by clicking on the wifi icon while holding down the option key.

I would consider outdoor coverage planning in this residential space.  For example the backyard/deck as appropriate.  Normally its cost effective to mount an indoor AP near the window.  Please test as some energy efficient windows can have considerable RF attenuation.

Good luck with your residential RF design!

[Len Levin]

This is great info.

I can't do your suggested test because there is no broadband installed at this time.

The RSSI info will be very helpful.

My one concern is computers switching from one radio to the next.  Is there something I can do, with a radio setting, to make sure the switch happens seamlessly, without the user knowing the switch has happened.

Thanks.

Len

[Leo Laohoo]

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@Len Levin wrote:
My one concern is computers switching from one radio to the next. Is there something I can do, with a radio setting, to make sure the switch happens seamlessly, without the user knowing the switch has happened.

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That will depend entirely if the wireless NIC drivers were updated or not.  If they are, the wireless NICs will be able to make a "smart" decision based on several "factors".

[tottenavl]

You should be able to create a test ssid and associate the client without broadband/internet connectivity.  We often refer to this as "active survey" or "ap on a stick" testing.  Search for those key words for more information.

Your question about healthy roaming:  I have found this to be one of the challenging parts in a residential design.  There are some vendor feature sets to encourage a client to roam, however the client ultimately has to make the decision to roam to other APs.  I would suggest the following starting configuration:

-Disabling the lower data rates (below 12Mbps)

-AP power is limited (11-14 dBm)
-Wlan using 5g radio only

What I typically see in a residential design(or non-design) are APs set to max power.  As the client moves around the house it stays connected to the same AP (sticky behavior) because the RSSI and SNR have not reach the roaming thresholdsj as the APs are set to max power.  Most clients (ios) will try and roam to the new bssid (AP) around -70 RSSI.

I hope this information helps!

[Len Levin]

Tottenavl,

Thanks for the info and taking the time to go into depth on this issue.  I won't be building out the network for a few months.  Once I am done I will come back and post what the layout was and how things ae working.

Len