Hello.

I have a network with 6 APs, every AP cover a certain zone of my yard, my clients roam without losing a ping from side to side of my yard and the connection is reliable most ot the time.
But sometimes i have problems with one station or two (of a total of 90) and the problems are caused by the same station roaming capability because the Mikrotik Groove start jumping from AP 1 to AP 2 and from AP 2 to AP 1 forever, I have identified this scenario.

Imagine two AP distant 500 meters, both AP with same omnidirectional antenna and same SSID, same tx power, same all.

One client station with station-roaming enabled, just in the middle of both AP, station will search for best AP every couple minutes or seconds (i do not know because Mikrotik has not expecified).

On first search AP 1 is seen as -70 dB and AP 2 is seen as -68 dB, station will roam to AP 2.
But couple of seconds later AP 1 is seen as -67 and AP 2 is seen as -71, station will roam to AP 1.

This happens forever and ever while the station is just in this middle point and the station start lossing connectivity because that, i think that is something related to ARP and MAC tables of APs and switches.

I think that we need a parameter to adjust the difference in rssi between AP 1 and AP 2 to trigger a roaming between them.

Please Mikrotik, you have this already done at 90% perfect, only a little detail more and is perfect!

Roaming is a client process and has NOTHING to do with MikroTik and other wifi router suppliers.

Many things can be done to fine tune your network such as using access lists and adjusting AP power.

You need to understand how wifi works, use tools to do a heatmap and adjust your APs' power outputs accordingly.

And remember, unless you have a very huge yard, less is better!!

Regards,

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If it's a MikroTik station that's roaming it has everything to do with MikroTik...

Not specified! And if you read the problem, possible design flaws, i.e. too many APs. Unless you live in a castle.

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Hello, thanks for your comments!

The yard have 2 km large and 500 meters width

The APs are Rocket M5 and the clients are Mikrotik GrooveA 52hpn in 802.11n pure mode (station roaming only works in 802.11 mode).

I know that roaming is something that must be done by the client, you can from AP side only force the desasociation of one client with access list but this lead to clients lossing ping and long AP searchs, my first try was with Ubnt and was a real shit. Bullets do not roam anything, they just sit down and wait to be disassociated from the AP and later they take a really long time to associate.

This is all about Mikrotik, is a really simple change that for sure can be done without too much problems and, for sure, will open a broad market like container terminals and ports, as we are.

About less is more, is reall, i have only one AP facing one area but in some weird cases the client receive signal from both AP and the issue happens.

Thanks!

You do live in a castle!

Do you have a rough drawing of ap positions?

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You do live in a castle!

Do you have a rough drawing of ap positions?

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Yes, my condos are incredibly bigs!

I am now at home, tomorrow i can post a drawing of the port (i mean marine port, with ships and containers and all this staff) but the problem it's real.

This is my "yard"
The APs are 90º side by side one of the other with 120º sector antennas.

The clients are Mikrotik Groove A on top of RTG cranes moving along the yard over the containers.

The joys of "off-line" discutions and using second and third langages.

When you said "yard", I never envisionned a shipping yard.

From the drawing (good job BTW!!!), are the dotted lines the areas that the APs cover? If so, way too much overlap. People always go on about a good amount of overlap. Some overlap, yes, but not too much. So perhaps lower power output. And also, you have tower 17 in the middle of it all. It could be adjacent-channel interference. That's always bad.

When in doubt, a good site survey will always be of value. The hardware and software can be expen$ive, but the results will save you a ton of pain. You'll "see" the coverage from all APs, and get results such as interference from your APs, from other devices you don't own, etc.

From the values that you get as RSSI (very small delta), I get your point now that maybe the STA should be a bit more "sticky". But since you cant configure sensitivity right now, perhaps you could try lowering power on one of the APs when the rig is in the middle of the yard, which would give you a bigger RSSI delta and have more predictable roaming.

Regards,

Hello.
Thanks for the congratulations.
I needed to design and install the network in 4 days, this is the better i can did with this time schedule, a long history to be told here.

The dot lines are only for documentation purpose, in reallity the coverage of tower 7 reach all the yard but in order to have a redundancy and divide the total equipments quantity over different APs because we are using 802.11 an not any TDMA protocol.

The total quantity of equipments is over 130 clients.

I am glad that i manage to explain the issue, now the job is to have Mikrotik involved and make this little change to RouterOS in order to improve the roaming capabilities, that nowadays are fantastic.

About tower 17, this tower in reallity is not needed but in the same tower, there is a Vodafone link and the noise near the tower is incredibly high in all the 5 Ghz and 2 Ghz band, because that, i installed a AP in the tower to cover the noise area.

Thanks for your words and for the help.

Is it necessary to have the same ssid to use the station roaming ? will not be a transition unless it is the same ssid ? I suppose it should be logical...

Hello.
Thanks for the congratulations.
I needed to design and install the network in 4 days, this is the better i can did with this time schedule, a long history to be told here.

The dot lines are only for documentation purpose, in reallity the coverage of tower 7 reach all the yard but in order to have a redundancy and divide the total equipments quantity over different APs because we are using 802.11 an not any TDMA protocol.

The total quantity of equipments is over 130 clients.

I am glad that i manage to explain the issue, now the job is to have Mikrotik involved and make this little change to RouterOS in order to improve the roaming capabilities, that nowadays are fantastic.

About tower 17, this tower in reallity is not needed but in the same tower, there is a Vodafone link and the noise near the tower is incredibly high in all the 5 Ghz and 2 Ghz band, because that, i installed a AP in the tower to cover the noise area.

Thanks for your words and for the help.

Is your issue now ever been solved by MT? How RU doing now? half a year after your last post?

With client settings, you can manage station roaming using client rules in the settings, by default they still use best power AP to change but you can change and add a rule to change only if lower than RSSI or something like.

But Mikrotik did not answer in anyway to my question, only managing by myself.

Roaming is a client process and has NOTHING to do with MikroTik and other wifi router suppliers.

As this thread was updated in 2019 I'd like to add a little to it here in late 2020. With the 802.11 extensions of 802.11k and 802.11v, roaming decisions may still be client based but the network can influence the client decision process.

This has caused a lot of confusion, and the other threads on "the lack of 802.11k/r/v in Mikrotik" have not helped answer the problem.
Put simply, at the time I write this a Mikrotik based wireless network needs to rely on the experience of the wireless designer. This means selecting the right locations for access points and setting the right access list rules for when clients are kicked off an access point based on their signal strength.

As and when Mikrotik introduce 802.11k and 802.11v (802.11r is less of an improvement here), we will be able to use CAPsMAN to influence when clients roam and which access points they roam onto. I look forward to this day as it will both stop the debate about the lack of 802.11k/r/v and we can just focus on solving issues with networks.