Wireless Network related Query

Hi gals / guys!

I have query relating to WiFi, its like this suppose there are more than one AP's in a Wireless network with same SSID and there are devices like Laptop, PDA's and other hand held devices connecting to them. Its been observed if device 1 is connected to AP1 and while roaming device 1 get close to AP2 but still its connected to AP1 although the distance b/w Device 1 and AP2 is much small than that with AP1. WHY is this so?

Some one told me that it will automatically connect to AP2 once the minimum signal strength value will reach. So if this is the case than what is that minimum value and can that be defined manually in a wifi enabled device.

Try changing SSID'd of both networks. This will answer all your questions.

You can even enable different securities on different AP's.

You may be talking about windows Zero Wireless Config software. If it is enabled it will connect to any network that has the best signal strength that is not encrypted. If you PDAs and portables are running Microsoft’s palm OS, or XP sp2, this is most likely the case.

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Originally Posted by manish soin

Try changing SSID'd of both networks. This will answer all your questions.

You can even enable different securities on different AP's.

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I agree, Each access point should have the same WEP KEY, but different SSIDs

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Originally Posted by Info Tech Geek

I agree, Each access point should have the same WEP KEY, but different SSIDs

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Why WEP?

This is probably a different setup than you have... but here is what I observed when I setup a wireless network.

I setup a 3 routers using the WDS repeater mode on wrt54g routers using the DDWRT firmware. At the time, only WEP WPAv1 was supported. I think that they now support WEP, WPA and WPA2. I used WPAv1 because of the weaknesses of WEP.

They all shared the same WPA key. I gave each the same SSID and just changed the scope of the DHCP server on each router so I knew which one I was connected to. As I "roamed" from one to another, it would knock me off the network and get another IP via DHCP. It wouldn't always switch from one router to another though just because one signal got stronger than the next. Just when the signal got too weak, it would drop off and connect to another one with a better signal.

I didn't care for this setup much and ended up just taking it down in favor of a wired LAN.

I too have had roaming setup (on a much larger scale) and found it to be somewhat crappy.

That said, I did find a commercial offering by Aruba networks that accomplished this in a VERY nice way. Reliably hopping APs was the biggest benefit and of course central management.

At the end of the day, wireless is cool but I'll take copper over wifi any day.


--TH13

phishphreek
Just when the signal got too weak, it would drop off and connect to another one with a better signal

This is what i Wanna know is there a specific value for this? I mean minimum value for signal where i get drop from one AP and get connected to the other one with best signal and can that value be changable or is it hardcoded in the devices?

As far as I could tell, no, there were no preset values. I'm not sure if there is software out there that would complish this or not. Most of the software I've seen for the actual network cards don't have a place to set the preferred network based on variables such as signal strenth. I've just seen where you can setup preferred APs by name.

I've never really looked into doing something like that as my wireless hosts were somewhat stationary for the time they were being used. The only thing that wasn't stationary was my PDA... I never paid attention to what that did because I turned on the wifi when it was needed. Otherwise my battery would be killed far to quickly.

Though, it looks like some manufacturers thought about this?

Google around for wirless clients and roaming. It is probably just based on the client and the adapter. Maybe there is a third party tool out there that will take over handing these types of variables? Not sure.

http://www.intel.com/support/wireles.../CS-015906.htm
http://www.cisco.com/en/US/products/...8014624c.shtml

Are you using standardized adapters? Check the docs on the adapters and see how they function with regards to roaming.

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Originally Posted by Info Tech Geek

I agree, Each access point should have the same WEP KEY, but different SSIDs

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I could be mistaken, but I've always understood that the SSID should be the name of the network the AP is connected to and it doesn't matter how many APs there are, they should all have the same name. It's the channel numbers that distinguish between the devices.

I have two, 3com APs configured to allow connections on three separate VLAN networks. Both APs have the same SSIDs (but a different one for each VLAN) and they seamlessly hand off the connections between each other as users roam from one section of the building to the other.

Doesn't having different SSIDs make it more difficult for roaming since the devices have to negotiate a new connection with a different SSID?

The technology around RFC 802.11 has been muddled quite a bit with the advent of consumer grade components.

http://www.linux.com/howtos/Wireless-HOWTO-9.shtml << best Engrish. EVAR!

That should shed perhaps a small bit of insight. FanacooL, are you using centralized management software, or just a couple of COTS ap/routers you bought at Bestbuy? Are you using Windows ZWC, the wifi management software that came with your various devices, or something else?

There are a LOT of questions relevant to your situation before a proper answer can be given. I am assuming you encountered something, are curious, and want to learn more about it and Wifi in general. Way too much info to discuss it here.

I have a few suggestions, if you really want to learn that much:
1- the NetStumbler forums used to be AMAZINGLY good at these sorts of specifics, if you knew who and how to ask. Thorn, Blackwave, Renderman, and many others have been hanging around there a LONG (LOOOOOOOOONG) time, and it's a good resource...or it used to be. I don't know how active that forum is anymore, what with the decline in popularity of NS thanks to Kismet, Airodump, and many many other tools.
2- 802.11 in a Nutshell (ok so it's not a Nutshell book, but it's darn near.)

My point being, there are a lot of points to consider. The short answer = change the ESSID of one of the access points and change the windows settings to not auto-connect. That should put the onus on the user.

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Originally Posted by zencoder

The technology around RFC 802.11 has been muddled quite a bit with the advent of consumer grade components.

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...one of the most flagrant being Mr. Richard A. Clarke's recent novel Breakpoint, whereby he writes:

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on Page 74:
"... WiFi transmitter sitting above on the traffic pole. From there, the digits moved through the air on a radio frequency, 802.11, to another WiFi box on a light two blocks away. ..."

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Uhm, this guy was our cyber-czar or whatever the f$ck the luddite head-in-the-sand majority-oops-no-now-they-are-the-minority leadership calls these new positions (why the hell does the U.S.A. need a CZAR for anything?!? I never understood that.)
Don't get me wrong, I like Clarke, but his book made me raise my eyebrows and wonder if this guy ever bothered to have a real bona-fide GEEK read his transcripts before submitting them. He supports technology and gets it...he's just not that tech savvy himself (I dare anyone to prove otherwise.)

zencoder

FanacooL, are you using centralized management software, or just a couple of COTS ap/routers you bought at Bestbuy?

Nope i am not using centralized management software, its like i have 4 AP's of Symbol Inc. And the clients connecting to these AP's are Laptop's and PDA's and each one of them has there own software for configuration. I am not worried about anything or there is issue the network is pretty much OK but its just the Curiosity to know the exact procedure behind this.