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Multiple APs should use different channels but the same SSID?

Hi. I'm just looking for confirmation that I understand the use of multiple access points in one open-plan office space. Am I correct in saying that each AP should be given the same SSID but be placed on different, non-overlapping channels?


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Re: Multiple APs should use different channels but the same SSID?

Yes, and to add to @NikolasZ's answer, the general advice is to set radio powers as low as possible.  typically this means 2G radio power to Low and 5G power to Low or possibly medium; you can also use RSSI in advanced settings to facilitate clients roaming to the "best" AP.

 

There is a bit of "artistry" though and trial and error in refining the setup!

 

In my guest house for example I have all my 2G APs on 1, 6 or 11 keeping APs on the same channel as far away as possible and on Low power and RSSI -75dbm.  In the 5G space I have all the APs on different channels and Medium power, with band seteering enabled and RSSi -75dbm (with them on low power in the 5G space I find most clients use 2G even with band seteering enabled)

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Re: Multiple APs should use different channels but the same SSID?

[ Edited ]

In short: Yes, you are correct.

 

There is probably a longer answer, as to  which channels should be adjacent to each other, output power etc, etc, but that would be an answer from a WIFI-professional.

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Re: Multiple APs should use different channels but the same SSID?

Yes, and to add to @NikolasZ's answer, the general advice is to set radio powers as low as possible.  typically this means 2G radio power to Low and 5G power to Low or possibly medium; you can also use RSSI in advanced settings to facilitate clients roaming to the "best" AP.

 

There is a bit of "artistry" though and trial and error in refining the setup!

 

In my guest house for example I have all my 2G APs on 1, 6 or 11 keeping APs on the same channel as far away as possible and on Low power and RSSI -75dbm.  In the 5G space I have all the APs on different channels and Medium power, with band seteering enabled and RSSi -75dbm (with them on low power in the 5G space I find most clients use 2G even with band seteering enabled)

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Re: Multiple APs should use different channels but the same SSID?

[ Edited ]

Yes. I hesitant a little to mention it, but there was guidance along the way (last 4-ish years) that suggested using the same channel for the following situations. These are not longer valid if you are running the recent firmware. 

 

     1) If implementing UBNT's zero-handoff

 

     2) If needing to perform rudimentary "fast handoff" 

 

ZHO is dead. Don't. Just don't. Recent firmware updates have helped with fast handoff...use unique channels. Work to improve "quality" of channels. 

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Re: Multiple APs should use different channels but the same SSID?

Hi Tim,

 

Each AP isn't limited to a single SSID, you can have up to 4. For example, in my home we have two SSID, one for the adults, and another for the kids which has time limits (turns off at 8:30pm). When we throw a party, I'll turn of a third SSID for the guest network.

 

But yes, generally you would want to set up all the AP's with the same SSID.

 

If you have a laptop, you can install software to see what the wireless spectrum looks like in your home and help you pick the right channels. I use a free copy of inSSIDer. It's super simple to use, And for home use is probably all you need. Keep channels for AP's as far apart as possible, and with minimal channel overlap from your neighbor's devices.

 

And use the least amount of power as needed. It was hard for me to accept this, as I wanted to crank the TX up to high on AP's, but as the experts on this forum point out, lower power is better. I fine tuned my setup by looking at the signal on client side and AP and try to keep them around the sameness number. I may only see fewer WiFi connection bars on my client devices, but throughtput actually increased when I did this.

 

 

 

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Re: Multiple APs should use different channels but the same SSID?

Thanks guys. Very much appreciated.

 

I'm intrigued about this idea of running the radios on less than full power. I think I need to do a little reading...

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Re: Multiple APs should use different channels but the same SSID?

[ Edited ]

maybe save you some reading....

 

Yes it can seem a bit counter-intuitive.  as @bcdouglas says there was a zero handoff option that enabled fast roaming.  Rudimentary fast roaming (but without zero handoff) on Unifi can be achieved by setting all the APs to the same channel; I have had my network set like that in the past when I had fewer APs.  This has the advantage that clients will move rapidly to connect to the AP with the best signal, however it has the disadvantage that it is technically "co-channel" interference; which means you effectively end up sharing the bandwidth between all the devices that can "hear" each other; it is though better than adjacent channel interference where the radio signals interfere with each other but being on different channels the listening devices have no way of co-operating to share the bandwidth. 

 

In many types of use (e.g domestic and  small hospitality environments) actually co-channel interference isn't as big a deal as is sometimes painted (e.g imagine a restaurant with lots of people's smart phones connected but actually any point in time few of them doing anything other than browsing a  few web sites, when the internet connection is far more likely to be the bottleneck; in a domestic environment, you and your family walk through the house and roam - and you are no longer on the other AP!)  - where it does become a bigger deal is where WiFi is being used in a corporate environment with connections looking to shift large chunks of data around the LAN, or a larger hospitality environment like a hotel with far more guests trying to do more substantive stuff with laptops. Another argument for this kind of setup in an urban area is you may not be able to use three clear channels due to thm already being used by networks you have no control over and co-channel is "better" than adjacent channel interference.

 

Therefore the preferred way of doing it in a commercial environment is as I described in my earlier post.  the reason for turning the radios down is because the AP radios and antennas are almost always much better than the radios and antennas in mobile client devices and so turning the radios down reduces the risk of any interference with other APs especially since if you have more than 3 in the 2G space and need to reuse channels, but without compromising the client's ability to see the APs and connect with a good signal (sicne the client device is the limiting factor).  The other reason and why using the rssi advanced setting helps is with roaming.  If you have all high power radios on different channels (1,6,11) and no rssi setting the client will try to hang on to its currently connected AP often until the signal is very degraded (and the RX/TX rate degrading massively as a result) rather than roaming to a better AP.

 

No doubt a purist will berate me for even discussing the co-channel settings - but what the hey!

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Re: Multiple APs should use different channels but the same SSID?

Trouble with "co channel" in residences these days is that pretty much ~everything~ is wireless. Not that @clarksn is wrong, mind you -- but there are many variables to take into account, and what may work for one person will not work for another.

 

You and your SO, and a couple of phones / laptops / chromecast ... okay, fine, keeping everything on one channel (or even one AP) may be entirely doable, as any one person can only be "using" so many devices at once.

 

"Average" (US) family of two adults and 2.5 children (or thereabouts anyway) ... the WLAN will more likely than not be more robust with all of your APs on different channels in order to maximize the available airtime for clients connected to each individual AP.  Granted, if everyone's connected to the same AP (e.g. the one in the hallway outside bedrooms) that kind of goes out the window.

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Re: Multiple APs should use different channels but the same SSID?


TimWatson wrote:

Am I correct in saying that each AP should be given the same SSID but be placed on different, non-overlapping channels?


I am somewhat confused by this discussion of giving APs the same SSID.  I thought that they way things worked in the Unifi world is that you create various WLANs and then you enable or disable the WLANs for your various APs.

 

You don't actually ever assign an SSID to a WAP, do you?  I will agree that the APs do broadcast the WLAN names as SSIDs but if I understand things correctly the discussion in this thread is a bit misleading.

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Re: Multiple APs should use different channels but the same SSID?

[ Edited ]

@wayner92, what you do is set up the Wireless LAN(s) in the controller.  The controller then provisions all the parameters for that Wireless LAN including the SSID to all the access points. You can have up to four Wireless LANs per AP.

 

Most people installing Unifi want to have the same SSID(s)(WLANs) available throughout an office, or industrial complex or hospitaility environment or home or whatever, and the ability for the users to roam freely within the environment.

 

You can over ride the settings locally in a given AP if you need to to turn SSIDs(WLANs) on and off for example, and other more complex configurations are possible including having multiple groups of WLANs, but the above is the common use-case.

 

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Re: Multiple APs should use different channels but the same SSID?

So, what will happen if i use MIkrotik as my router and use UAP-LR as my AP but the SSID abd password of two devices are the same? if it possible or not? 

 

My wonder is if we can do it as roaming WiFi it helpful. 

 

Thanks for advance! Blessing 

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Re: Multiple APs should use different channels but the same SSID?

With the setup you mention, as long as the SSID, password, and security encryption settings are all the same then roaming will work. Make sure to put the Access Points on different wireless channels so they don't interfere.

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Re: Multiple APs should use different channels but the same SSID?

To piggy back off this discussion, should I use bandsteering if I am in the same situation as the OP; running 2 AP's in a 2 story house, and want handoff with the same SSID on both AP's?

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Re: Multiple APs should use different channels but the same SSID?

Any ideas? Or do I need to start a fresh thread?


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Re: Multiple APs should use different channels but the same SSID?

[ Edited ]

Thats up to you. If you want the clients to favor 5ghz, and you have good 5ghz coverage, then use bandsteering to push them to that frequency. Otherwise just create 2 different ssids and name one YourSSID_5g and the other YourSSID_2g , then you decide which to connect to.

 

To add to that; Do a wifi scan of the area, if its congested and you have good 5ghz throughout the house I would shut off 2ghz altogether if possible. If you have devices that can only use 2ghz then band steering is the best way to go.

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