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petrsebecek
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Wireless client roaming

Thu Feb 02, 2012 6:28 pm

Hello,
I want to ask about a wireless roaming for mobile users (2,4Ghz - short distances). All APs are connected by cable to LAN. Distance between APs is about 20 meters. Eth and Wlan interfaces are together in the bridge. I use radius authentication of MAC addresses at User Manager. I have a problem that the client is still switches between APs. I want to achieve the client connection to AP with better signal.

Please, anyone, can you help me?
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brandonrossl
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Re: Wireless client roaming

Thu Feb 02, 2012 10:32 pm

The client's device does the access point choosing when the network and authentication are the same. You can only provide better coverage through picking the proper, alternating, non-overlapping channels so that access points don't fight for the same frequency.
 
n21roadie
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Re: Wireless client roaming

Fri Feb 03, 2012 12:53 am

You could try setting in the connect list "signal strength range" to say -80 and when signal drops to that it should rescan and reconnect to the strongest signal.
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WirelessRudy
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Re: Wireless client roaming

Fri Feb 03, 2012 1:54 am

Are you talking about a moving client? Or static?
When you talk about a moving client it would be very normal to expect client switches between AP.
When you talk about static client you do a scan, pick the best AP and by means of the 'connect-to' list in the client make him to use that AP only.

Like n21roadie states, you can set a threshold on the client to have him drop an AP if the signal drops below a certain level. But as long as client is associated to an AP within that threshold it will not jump to AP with better signal.
To have a client always go for the best signal would mean the radio has to scan continously available AP's and test their signal. Since your 5 AP's are close to each other and in a band where you basically only have 3 relatively separated channels available your client have to deal with interferences. This also means signal strenthgs as beeing received by the clients receiver are fluctuating a lot. (They already would do if there was only one radio. Even then the signal differs).

Whatever your solution now is, you have to consider that everytime a client has to jump to another AP the communication is interrupted. This will have a negative impact on the throughput.

You would stand a better change for moving client to setup a mesh network where client can freely roam between AP's and AP's are working together not to interfere with eachother.
I think you also stand a better change for a smooth operating network when you'd use less AP's but mimo type ones. Do you really need so many AP's at such short distances?
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TheWiFiGuy
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Re: Wireless client roaming

Fri Feb 03, 2012 9:27 pm

Are you running the APs on different channels (1,6,11,1) etc?
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petrsebecek
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Re: Wireless client roaming

Tue Feb 07, 2012 4:22 pm

Hi,
thanks for responses.

n21roadie: I can't use connect-list, because I'm using User Manager for MAC authentication.

TheWiFiGuy: Yes.

WirelessRudy: All are moving clients. Can you help me a little with mesh network? I read somethink about HVMP (http://wiki.mikrotik.com/wiki/Manual:Interface/HWMPplus), but I don't understand this one very well :(.

The question at the end which I should have said much earlier. Go to the Mikrotik was the right decision? :)


Regards,
Peter
 
broadband
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Re: Wireless client roaming

Tue Feb 07, 2012 4:35 pm

Hi,

What about the envorinment? inside the building or outside the building? obstacles? Possible the use UBNT Rocket (TDMA must be off) with a sector antenna? Try to use the highest antenna gain as possible..

Regards

Ali
 
petrsebecek
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Re: Wireless client roaming

Thu Feb 09, 2012 2:52 pm

Hi,

APs are RB411AH with R52N-m and two 7dBi omnidirectional antennas for indoor use. Units are located near the ceiling six meters above the ground. It's a factory envorinment...


Peter
 
petrsebecek
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Re: Wireless client roaming

Fri Feb 17, 2012 5:53 pm

Hi,
resolved. I was configured the AP setting through the auto-script and the same MAC was apllied to all APs... :D
My BIG mistake.

Thanks for your time.


Regards,
Peter
 
leoalzinger
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Re: Wireless client roaming

Mon Feb 20, 2012 1:36 am

Hi,

I have exactly the same problem and I have not understood how exactly you have solved the problem. I am new to routeros so could you please explain to me how you have solved this?


Leo
 
petrsebecek
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Re: Wireless client roaming

Mon Feb 20, 2012 4:07 pm

Hi,
OK.

You have a some routerboards (RB411s in my case). Put eth01 and wlan1 to the bridge, set same SSID and security profile on each RB, but You must have different frequency channels - You can set up it manually or automatically (DFS mode set to no radar detect in advanced mode). Connect all RBs through switch and assign IP to each bridge interface. You should run DHCP server on some RB or on another machine/RB (no AP)/server.

That's all!


Regards,
Peter
 
leoalzinger
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Re: Wireless client roaming

Wed Feb 22, 2012 12:09 am

Hi!

Thank you, so far everything is clear to me.

But I have one more question. What did you mean with "the same MAC was apllied to all APs..." in your post from 17th february?

regards
Leo
 
jacob25
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Re: Wireless client roaming

Sat Feb 28, 2015 5:25 am

well, I go through all reply. I also want to know what do you mean "post all MAC address to all APs"? Should the AP exchange all client MAC address?

Jacob Liao
 
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Re: Wireless client roaming

Thu Dec 14, 2017 12:13 am

As far as I can tell, Mikrotik does not get it. A moving terminal, lets call it a mobile, and multiple fixed stations must use what we radio people call "diversity". Diversity could be as simple as switching fixed stations in accord as to which one has the strongest signal. I believe the mobile could work with multiple terminals all at the same time if they all had the same MAC, and were synchronized. By synchronized, I mean the radio transmissions intended for the mobile from all fixed stations would be close to the same instant and on the same exact frequency. The more simple technique should work on the existing non synchronous capable hardware. Simple. Switch the transmitted packets off except for the fixed station receiving the strongest signal from the mobile. send packets from the mobile to a central switching unit only if they came from the fixed station receiving the strongest signal. I bet that is possible with existing hardware and only minor modifications of Mikrotik OS. There would need to be a central station controller that would manage it. That requires some additional software.

I think you can set up access points to use the same SSID and all have the same wireless MAC. That would mean the mobile could not tell what fixed station it was talking with, and will treat all that are receivable as interference. Likewise, all the fixed stations will think the mobile is registered and send the same mobile packet on to the LAN. Right?

Maybe it could be done with existing Mikrotik OS, and as I am not expert in it, I do not know what commands can be loaded. That it seems not to have been done tells me it is difficult if it is at all possible. Anyway, think first about packet switching diversity. If you like, look up diversity radio reception on your favourite search engine. -ok... back to sleep.
https://en.wikipedia.org/wiki/Antenna_diversity Check spacial.
 
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Petri
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Re: Wireless client roaming

Thu Dec 14, 2017 1:07 am

@Lansman You have just described Single Channel Architecture (SCA). It requires co-ordination between the access points, so it is not possible to set up with RouterOS. Some vendors do support it, Meru is the biggest proponent AFAIK. Ubiquiti calls it Zero Hand-Off (ZHO). It does have some advantages and use cases, but also many drawbacks. There are multiple sources on the net, now you know what to search for.

(Were you aware that you replied to a thread that was a couple of years old?)

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