Hello @L.M.,

 

These are all great questions.  It sounds like you are doing all of the right things and have looked into it thoroughly.  But, it seems like your AP transmit powers are probably set too high.  You have 6 AP's spread over what kind of square footage?  (I realize 2 are outside).

 

As I sit here now, I'm getting ~300-350 Mbit/sec on my XSM from an AP one floor below (approx 15-20 feet away) with an RSSI of -69 (Link rate is 526/866).

 

So as you can see, -69 or -70 is not a bad signal level.  Note that the RSSI is the return (aka the signal the client is transmitting back to the AP) this signal is generally weaker than the signal coming from the AP.  But the client will decide when to roam based on the signal it sees (which is the transmit power from the AP).

 

Additionally, unless you have a massive house, having 4 AP's inside plus potential signal from the outdoor AP's is liable to cause a fair amount of interference / signal overlap unless you have the transmit power turned way down, and you are using narrow channels.  Are you in the USA?  In which case there are a limited number of channels to work with depending on the channel BW you are using.  These TP link products (I have 1xOC200, 2xEAP225 myself) do not support DFS channels in the 5GHz spectrum, so there are ownly 2 non-overlapping channels at 5GHz.

 

What is the goal of your installation?  Are you trying to maximize high speed file transfers?  Or just have a reliable signal throughout your house?  Step 1 is to get a good Wifi signal visualization tool like inSSIDER.  The light version is free and they make it for Mac & PC.  It's a great program.  Does you MacBook have 3x3 antennas?  802.11ac, I assume.

 

For troubleshooting, I would try the following things.

1) Disable band steering and use separate SSID's for 2.4Ghz and 5.8GHz

2) Ensure your firmware is up to date on everything

3) It sounds like you already have fast roaming enabled.  But I would turn off Force Dissociate for now

4) disable any load balancing settings you have enabled for now.

5) Set the transmit power on all AP's (both radios) to Medium.

6) Do not use automatic channel selection on any of the radios.  You'll need to set them manually

 

For the AP's that are closest together (none should be closer than ~20 feet), for 2.4GHz use only 20MHz BW, and set channels 1,6,11 (if in USA, and no neighbor interference).  Then for the next two (in terms of proximity to the first three), use channels 3 and 9.  Finally for the 6th AP, use one of the prior 5 channels that has the lower signal when you stand at the 6th AP (use inSSIDER).  Since the 2.4GHz signal travels very well, you may need to disable one or two of the 2.4GHz radios or experiment with turning down the AP transmit power even lower.

 

Now, in the 5.8GHz you want to try to do the same thing.  BUT, the problem is that at 80MHz (which I assume you're using to try and get optimal speeds) there are only two non-overlapping channels (this would be 3 or rarely 4 if the devices support the DFS spectrum).  So for now, I would recommend you set the BW to 40MHz @ Medium transmit power for setup and troubleshooting.  Later you can potentially increase one or two of the AP's to 80MHz if they don't overlap too much.

 

At 40Mhz, you'll have 4 available channels.  So you can follow a similar approach to the 2.4GHz spectrum, except you'll have one less channel to work with.  Certainly some AP's radios can be configured to use the same channel, but you want to try and keep them as far away from one another

 

At my work we have a very high density of AP's (every 20 feet or so in an open office space) and they had to use 20MHz channels on 5.GHz to minimize the overlap.  Which kind of stinks as I only get ~110 Mbit/sec or so on my laptop (2x2).

 

-Jonathan