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How can I change the way Macbooks roam on the WiFi network? I would like to speedup the roaming of Macs (and maybe other devices).

Is there a setting on the Airport base stations or in Mac OS to speedup AP switching for example?

Currently the network is built around 1 main Switch interconnecting 1 router and 4 Airport base stations using the same SSID:

  • 3 dual band Airport base stations
  • 1 Airport 2.4GHz base station

On the 5GHz band, there is no overlap as each base station uses its own channel.

On the 2.4GHz band there is a very slight overlap between 2 base stations which are at opposite sides and at different stories of the building.

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What exactly is the problem you are experiencing? Is switching networks slow for you? Under which conditions are you switching networks? –  Gerry Oct 10 '12 at 11:59
    
@Gerry: When moving from one room to another I loose the connection just long enough for airplay to stop, file shares to stop responding, and Time Machine sometimes manages to keep on going but sometimes not. It will be a major issue for the users using the WiFi network. –  Coyote Oct 10 '12 at 12:02
    
Are you moving between access points with different names, or do the different access points all have the same names? –  nthonygreen Oct 10 '12 at 13:31
    
@anthonyg I updated the question with more details. Yes they use the same SSID each is setup to different channels, on the 2.4GHz band there is no or negligible overlap. –  Coyote Oct 10 '12 at 14:16

4 Answers 4

up vote 2 down vote accepted

No. There is no setting to drive this or configure things from the OS X side of things or the Airport router side of things.

As magiconair answers, you would have to script this renegotiation as a task using various tools, but if you don't want to program something or find an app that does this (I know of none, but the world of apps is large and growing), you might need to just force a re-join when you notice slowness or have physically moved locations.

By periodically forcing the Wi-Fi to disassociate with the network and then reestablish a connection, your device is much more likely to be connected to the strongest measured base station rather than hanging onto the first base station it joined.

The software is designed to keep a fair connection alive as long as possible rather than hop around always looking for a better connection.

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How can you do this? –  magiconair Apr 1 '13 at 20:44
    
On iOS, I usually turn off WiFi in settings. You could also toggle AirPlane mode. Taking more time is to "forget" and then re-join the network or scan and select an alternate SSID and then select back to the one you want. Walking out of range also does the same thing, but sometimes you can't or don't want to walk and prefer to drive things on the device's screen. –  bmike Apr 1 '13 at 21:27
    
Ok, that is the brute-force method which doesn't really address what the original poster was after. Namely, that he would not like the connection to drop when he is out of range but rather to switch to the better access point. BTW, '/System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport -z' does the same thing. –  magiconair Apr 2 '13 at 19:03
    
@magiconair Great comments - I've revisited the question and tried to make the answer more direct in the "no" - you can't do this with Apple's tools directly (as well as pointing to your scripting solution). –  bmike Apr 2 '13 at 19:38

I have the same problem but don't have an answer. However, I may have a path for further exploration. The airport utility on ML still has a legacy option to perform a WiFi network scan.

airport -s           # full scan
airport -s<SSID>     # scan only for SSID

The tool is under

/System/Library/PrivateFrameworks/Apple80211.framework/Resources/airport

and my suspicion is that triggering a scan also triggers a handover if another base station is better since the results are sorted by signal strength. Having said that one could write a tool which pings the default gw and triggers a scan on packet loss. If I have some time I will give it a shot.

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If you get some good results with that keep me posted. –  Coyote Jun 23 '13 at 11:55

I face this issue in small businesses that with OS X. I have yet to find a good solution other than disconnect and reconnect to grab the closer IP.

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In my setup the IP is assigned by the same DHCP server for all APs. All devices are on the same network with the same IP range. –  Coyote Apr 25 at 21:40

You can change the system preferences for JoinMode and JoinModeFallback to be the following:

    JoinMode (String)
        Automatic
        Preferred
        Ranked
        Recent
        Strongest
    JoinModeFallback (String)
        Prompt
        JoinOpen
        KeepLooking
        DoNothing

Do this using the airport command:

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport

Run the command to see the options, up the top you'll see a section on how to sec preferences.

For instance:

sudo /System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport prefs joinMode=Strongest
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