Roaming thresholds and aggressiveness on AirPort

I have a problem with my AirPort adapter wanting to "roam" between access points that are broadcasting the *same SSID*. Please note that my problem is NOT switching between two different SSIDs. My problem is associating with one AP, whose signal is the strongest of three that are within radio reach of my laptop, then switching to another AP, whose signal happens to be broadcasting stronger for a few minutes, then switching back to the other AP, etc., etc. This happens many times an hour and destroys my web sessions because I'm being NAT'd behind a different public IP each time I switch to another AP.

The solutions are: 1.) move closer to one of the APs, 2.) move one of the APs closer to me, 3.) restrict my mac from associating to 2 of the 3 APs so that I'm only allowed on one of the three APs, or 4.) reduce the tendency of my AirPort adapter in my MacBook to "roam".

#1 isn't feasible because my apartment is small and there really are only so many places that I can put my couch, chair or desk - the places where I use my laptop. Also, it seems as though I would still have the issue because the signals from each AP seems to be equally strong throughout my apartment.

#2 isn't feasible because I spoke to the ISP that is supporting the wireless network and they said there are limited places to mount the APs due to access issues, Ethernet issues and spacing issues throughout the entire building. They want to help but aren't able to because of physical limitations...sort of like my own limitations within my apartment - there are only so many good places to put a desk, couch or chair, whatever.

#3 isn't feasible because the ISP says the vendor only supports network-wide blacklisting. They can't block me from associating to just an AP. They can only blacklist my mac-address from the entire network. It's supposedly an "intelligent" mesh network of Meraki access points. But not that intelligent.

#4 seems to be the closest to a possibility that I would be able to have in my control. My friend's DELL wireless adapter has "roaming decision" and "roaming tendency" settings that we tweaked and his problems immediately ceased. He stayed associated to an access point for hours on end after we reduced the roaming aggressiveness. More details can be found here: http://support.dell.com/support/systemsinfo/document.aspx?c=us&l=en&s=dhs&~file= /network/wlan/en/ugen/props.htm#toc89 Also, if you google "roaming decision" or "wireless roaming sensitivity", all of the results are about the Dell's ability to allow you to control this behavior. Most of the responses I got from Apple on the subject are "Naturally, you would want to connect to the strongest signal." But my argument is that the signal of on AP is only stronger for a few minutes, then another signal trumps that one, and I break association with the first AP and associate with the new AP, lose all of my web sessions, then associate back to the other AP when its signal is once again stronger. This happens many times per hour. The Dell exhibited the same issue until we made the roaming less agressive.

Has anybody had this issue and have you been able to find a work-around for the Mac? Dell tackles the problem head-on, by letting the end-user decide how aggressive the roaming tendency of the card should be, but I can't find any setting, through the GUI or the command line, or third party app that will let me tell my Mac's AirPort how aggressive I want it to be. I want to tell it, "associate to an AP, then stay on it!"

Please help! Thanks in advance.

Message was edited by: myapplesrock; changed "mac" to "mac-address" for clarity.

13" MacBook, Mac OS X (10.6.2), Server, Clients, Base Stations and Handhelds

Posted on Dec 23, 2010 1:36 PM

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4 replies

Jan 2, 2011 11:40 AM in response to myapplesrock

I have same problem. I just setup my AP system in my home. 2 Linksys WRT54GL+DD-WRT firmware and set it same SSID and network key. my main point is how I know airport can switch between AP or not? I not see any setup function in airport preference just like "myapplesrock" ask for.

And how about mobile device like iPad or iPhone,Can they roaming?

Sorry for bad English.

Message was edited by: Xess666

Jan 4, 2011 12:30 PM in response to Xess666

To answer your question, Xess666...

By holding the OPTION key and clicking on your AirPort icon in the toolbar, you will see extended information about the network to which you are connected. If you look at the BSSID entry, you'll see a mac-address. That mac-address is unique to your access point. I think OPTION + click on AirPort is only supported in 10.5 or later...maybe 10.6 only, I'm not sure. I'm pretty positive it's not supported in 10.4.x

This does not, however, answer my original question, but yes, slightly related to it.

Jan 5, 2011 4:04 PM in response to myapplesrock

The problem is very simple, but I doubt you want to hear it.

Your ISP's network is improperly setup. If they are using the same SSID it should be the same network accross that SSID, but as you stated, it obviously isn't. Were it to be the same network your computer would switch to the access point with the strongest signal and that would be the end of it, since its the same network you wouldn't even notice.

What is happening is, since your ISP has multiple networks with incorrectly the same SSID on each is the roaming works as it should but then you have no IP connectivity any more, and your system requests a new DHCP lease at which point all open TCP sessions drop. Fun, isn't it.

The simplest method for your ISP to fix their broken network would be to change all the SSID's (e.g instead of having BrokenISP as the SSID on all. one AP should be Broken0A3A, another one should be Broken03FE, etc. In this example those 4 characters can be the last 4 of the AP's MAC address)

Some of the workarounds here might work, but in my eyes the ISP is a business and yet they manage to have a broken network. I doubt you would patronize a restaurant with salmonella in the food, so why would you patronize an ISP with a broken network?

Jan 10, 2011 1:02 PM in response to Andrew Joakimsen

I'm still looking into this to get more info about the network. What I want to hear is that the broken ISP will fix their network AND Apple will offer a roaming tendency/aggressiveness control on the AirPort. The Dell in question works flawlessly once we de-tuned its roaming tendency. I prefer to have the power in my hands and not have to rely on outside help. Thanks for the feedback.

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Roaming thresholds and aggressiveness on AirPort

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