TP-LINK OMADA components and roaming

TP-LINK OMADA components and roaming
TP-LINK OMADA components and roaming
2020-04-19 20:57:24 - last edited 2020-04-21 10:01:17

Hi.

I've bought, 1x oc200, 2x eap225 outdoor, 4x eap245 (everything connected by GE switch).

 

This setup works really good inside/outside my home and garden.

The only issue I have is that from time to time, end hosts does not switch to the AP with a much better signal.

 

Mobile phones roams more often, but for example my mac book pro can stay with much worse signal for a very long time (it can catch -69 and stay for a long time while it is 2 meters from another eap245 and signal aroung -45).

 

I have read a 100% of documentation, and have few questions,

 

1) Roaming settings,

 

"Fast Roaming"
With this option enabled, 11k/v capable clients can have improved fast roaming experience when moving among different APs. 

 

^ I understand that, and it its enabled.

 

"Force-disassociation"
The OC200 dynamically monitors the link quality of every associated client. When the client’s current link quality drops below the predefined threshold and there are some other APs with better signal, the current AP issues an 11v roaming suggestion to the client.
With Force-disassociation disabled, the AP only issues a roaming suggestion, but whether to roam or not is determined by the client.
With Force-disassociation enabled, the AP not only issues a roaming suggestion but also disassociates the client after a while. Thus the client is supported to re-associate to a better AP. This function is recommended when there are sticky clients that don‘t roam.
 

^ I understand that and it is enabled, but the doc says about 'the predefined threshold’, so what is the level of this threshold? There is nothing more at the docs.

 

2) AP Load Balance

 

"RSSI Threshold”
Enable this function and enter the threshold of RSSI (Received Signal Strength Indication). When the clients' signal is weaker than the RSSI Threshold you've set, the clients will be disconnected from the EAP. 

 

I understand that feature (enabled and set for tests -70 level), but have two questions:

a) what happen when user will not have any more ap with better signal, and exceed the threshold set on the ap? will the oc200/ap disconnect the user?

b) is this function connected with the "Force-disassociation" feature? In other words, is it 'that' threshold which is being used by "Force-disassociation" feature?

 

If the "Force-disassociation" does not depends on "RSSI Threshold”, then which of them has a higher prio?

 

Best regards.

L.M.

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Re:TP-LINK OMADA components and roaming-Solution
2020-04-20 13:31:14 - last edited 2020-04-21 10:01:17

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

 

 

 

 

 

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Re:TP-LINK OMADA components and roaming-Solution
2020-04-20 13:31:14 - last edited 2020-04-21 10:01:17

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

 

 

 

 

 

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Re:TP-LINK OMADA components and roaming
2020-04-20 14:15:56 - last edited 2020-04-20 14:20:08

Hi Jonathan. I'm not able (dont know why) to respond with quote, so please forgive me that. 1) I confirm, 4x EAP245 are inside a medium building with 7 rooms, and about 150m2 in total. 2x EAP225 cover the outside area around 2500m2. The area is surrounded with forests, there are ZERO 5 Ghz interferences from the outside. 2) First of all, the most important things for me are: low jitter/low latency, next throughput (but now lover than around 150 mbit/s). With -70 signal, the jitter is goint extremely high, and I archieve lags with real/audio applications. I use 40 Mhz channels in 5Ghz, and live in Europe Poland. For now, I dont care about 2,4 Ghz, it is being use by non critical devices which not roam. 3) The goal of installation is to deliver not lover than 100 mbit/s for each wifi client, but the most important are low jitter and latency AND VERY IMPORTANT -> extremely good roam. 4) My MBP has 2x2 ac, and I achieve with NO problems around 500-600 mbit/s at any place in the building (the same form my iphone xr) To be clear, I have no problems with signal strengh, and troughput. I want to force stations to roam more agressive, to get better signal from better AP to achieve excellent jitter/latency. I believe, that answers for my main questions will help me in resolving roaming issues. Best regards.

 

 

P.S-I use different static SSID's for 2,4 and 5,0.

P.S-2-500/600 mbit/s with 80Mhz channels.

P.S-3-the transmit power is set for medium.

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Re:TP-LINK OMADA components and roaming
2020-04-21 12:09:27

Hi.

 

I did a lot of tests within 5 Ghz.

As I said, my target is to achieve best real/audio quality in the context of low jitter/latency, and 100-150 mbit/s troughput.

 

The optimal settings are,

 

1) As you mentioned, I have decreased the tx power from MEDIUM to LOW, so I'm getting about -70 in the worst scenarios at the building within the same room (still able to get 100-250 mbit/s), and kept 80Mhz channels, jitter/latency are good.

2) With these settings, about 95% scenarios with roaming passed very well, but from time to time my MBP stays with -80 :/ (then jitter/latency very poor).

3) I have activated again the option 'Force-disassociation', but my MBP still stays with -80 (from time to time), It looks like this function does not work at all.

4) Enabling again the option at all AP Load Balance -> RSSI Threshold with -70 get the expected results -> ALL my device roams very well and do not wait to understand that they should change the AP, they get the best signal as posiible all the time ;-).

 

I could be very nice, to know how exactly the options like 'Force-disassociation'(what is the threshold) and 'Load Balance -> RSSI Threshold'(what if there are no any alternative APs with better signal) works, and if there are any connections between them?

 

Best regards.

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Re:TP-LINK OMADA components and roaming
2020-04-23 17:46:54

Hi @L.M.,

 

Just wondering what audio/video/VOIP apps you are using that are so sensitive to latency and jitter.  All of our telepresence stuff these days (Skype Business, Microsoft Teams, Zoom, Webex, etc.) all seem very tolerant / insensitive to subtle variations in wifi performance.

 

Of these, Skype Business seems to be the worse from our experience -- but most of its issues are server side or related to logging in / etc.  Zoom audio and video quality is very good.  Our VOIP telephones are all hardwired.  But its not like it really matters very few people (in our shop) actually talk on the phone any more. (-:

 

-Jonathan

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Re:TP-LINK OMADA components and roaming
2020-04-23 18:34:50

Hi, the most demanding? EoIP encapsulated udp video multicast traffic.

Regards.

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