Backwards thinking - forced re-connect

A lot of folks want to prevent automatic re-connects when wandering around overlapping wireless coverage areas.

I'd like a way of _forcing_ a disconnect and reconnect as soon as the signal strength of the new AP is enough greater than the old one's to assure I'm now solidly in the new coverage area.

This ties in with my project of pushing a new splash page as a roaming wireless workstation connects to a new zone.

Are there any tools already fashioned for that purpose?

LLoyd

Reply to
Lloyd E. Sponenburgh
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Use the force (i.e. MSDOS).

Start -> Run -> cmd net stop wzc do your thing followed by: net start wzc With luck, the new connection will be to the stronger AP. I don't know any way to do it automagically using your selection criteria.

Otherwise, use a connection tool that manages connections by MAC address instead of just SSID. For example: ($18 students, $35 other) This way, you can manually select the strongest AP to connect.

Hammer, mallet, assorted weapons of destruction, etc...

Reply to
Jeff Liebermann

Jeff Liebermann fired this volley in news: snipped-for-privacy@4ax.com:

Yeah... I've got the Intel Pro-Set wireless tool, and it has that feature.

I suspect a competent programmer could put together a background task that "watched" signal levels, and did the same steps automatically as if by hand.

But I did not say, and should have, that each of these zones can have a different SSID. In fact, that would be appropriate in order to identify their association with a specific building.

Would that change the nature of the task? LLoyd

LLoyd

Reply to
Lloyd E. Sponenburgh

On Mon, 22 Dec 2008 11:46:24 -0800, Jeff Liebermann wrote in :

If you have a computer by IBM/Lenovo (e.g., ThinkPad), ThinkVantage Access Connections will do that and more, and is free. Recommended, both the hardware and the software.

Reply to
John Navas

Welcome to the search for the holy grail. In this case, it's called seamless roaming.

Methinks you're asking for the impossible (or the rediculous). All the fast roaming specs are based on one assumption, that you want to connect to a specific network as identified by a specific SSID. If you want to connect to *ANY* random network, regardless of SSID, the algorithm must be very different. For example, you will need a list of included acceptable SSID's. You'll also need an exclusion list to avoid black holes, slow networks with strong signals, and other undesireables. Fortunately, there is software that does some of this. See:

It has a list of known open access points and automatically connects you when in range. However, under the surface, it's just another wireless connection manager. I've played with it on my XV6700 Windoze Mobile phone. No conclusions yet.

If this is unacceptable, someone (not me) can scribble a VBS script that takes the output of the Windoze network status commands, filters the mess for SSID, signal strength, SNR, or whatever your fancy, and determines whether to change connections. It's easy enough in Vista, where the incantation: netsh wlan show networks mode=bssid delivers the desired info. However, to do the same with XP or W2K would require a program the excavates the numbers from the NDIS driver. Once you have the data and decision mechanism, it's impossible to swap AP's without losing the IP address. Well, not exactly. If your network of AP's has Cisco or 3com proprietary roaming features, you can do seamless roaming. But with a random mix of commodity routers, forget it. The best you can do is issue a disconnect command to the driver, and then reconnect to the new AP. If I find anything useful, I'll send it your way, but offhand, I suspect this is a major project.

Reply to
Jeff Liebermann

I forgot to include the necessary incantations (which only work in Vista). To connect: netsh wlan connect SSID="YourSSIDhere" To disconnect, it's something like: netsh wlan disconnect interface="Wireless Network Connection"

See:

for examples, details, and whatever else I forgot.

Reply to
Jeff Liebermann

"Lloyd E. Sponenburgh" wrote in news:Xns9B7C937F4F7C8lloydspmindspringcom@216.168.3.70:

Lloyd, check out WiFi Hopper.

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I'm not sure it has a mode that is completely transparent (to the user), but it's worth a look.

Reply to
DanS

Jeff Liebermann fired this volley in news: snipped-for-privacy@4ax.com:

Not an issue.

Even with the slow (no... ponderous) "recognition speed" of the PROSet wireless software, I can launch a batch script upon connection to any particular SSID.

Upon launching, the first thing it does is clobber the previous instance of IE, and run a new one, targeted to a new URL.

I don't want "seamless" roaming, I want automatic roaming with distinct "seams"... a different instance of my software to launch every time a new SSID is connected to.

I just wondered if there were any pre-built tools that could do what PROSet can, but rather more quickly, based upon recognizing a signal- strenght advantage.

LLoyd

Reply to
Lloyd E. Sponenburgh

That's going to be fun. You appear in an area with lots of access points available. You laptop immediately connects to all of them, opening a new browser for each connection. Are you sure this is what you want? Obviously, I'm missing something here. Could you describe how you expect this thing to operate or be used? Better yet, what problem are you trying to solve?

Probably. Recognizing that a better signal is available is fairly easy. Switching is the PITA. In some seamless roaming implimentations, the wireless client connects to two or more access points simultaneously and then switches traffic only to the strongest or best SNR AP. I think that's the way Cisco's nSEF works (but might be wrong):

There is also wireless fast BSS switching or fast roaming:

What you're asking is (apparently) for the wireless client to do everything involved in the switching. It can do most of it, as you've seen with Proset, but not the ability to continue the session from a different AP. You're asking for a new session every time it finds a stronger AP, so seamless handoff is not a problem. However, I don't see your method as being particularly useful.

Reply to
Jeff Liebermann

Jeff Liebermann fired this volley in news: snipped-for-privacy@4ax.com:

describe

Ok... I didn't describe it fully, depending upon a group-memory of my past endeavors in this vein.

Here 'tis:

I have a number of buildings in which I will install wireless APs, each with an unique SSID. I will control their range so that they either barely overlap, or not at all.

I will walk around from building to building, expecting a body of software unique to each building to launch. The launch process will kill any old instances of any similar software before launching the new one -- so there won't be many instances of (say) IE running at a time; only one, ever.

The purpose is an inventory-taking/ordering system effected via a wireless-connected palmtop. Each building will have its unique order- entry page that describes items unique to that spot.

I've already successfully done this using XP, IE7, and Intel's PROSet wireless control software.

Each SSID's profile launches a batch script, upon connection, that first issues a "taskkill" to snuff the prior (or none) IE application, then launces IE again with a different URL, unique for each building.

I'd like to speed up the process, so that as soon as I walk into a zone "XX"dB stronger than the one I just left, it will force a disconnect and re-connect in a few seconds, rather than the minute-to- several it takes to recognize the condition now.

LLoyd

Reply to
Lloyd E. Sponenburgh

"Lloyd E. Sponenburgh" fired this volley in news:Xns9B7CC4F3BF957lloydspmindspringcom@216.168.3.70:

I should have added, in response to your "useful" comment:

Each building will have 'transactions' permitted ONLY for that building, and those must not be available when in any other building.

Spawning a new session for each building makes it pretty simple to open the database particular to that place, and makes the software simpler, since it doesn't have to filter site-specific info.

LLoyd

Reply to
Lloyd E. Sponenburgh

It would be much easier to answer your question if you told us what you want to achieve. If it's a greater discrimination agaist APs with greater field strength you want, so that it won't switch AP before it find one that got X dB better field strength, I'm afraid this is not supported by any client. This mechanism probably lays in the firmware and not the driver which makes it an impractical sollution if your users got more than one brand/model of wireless. I really don't understand what's the point by disciminating clients from what AP they are connectied to. If it's a security problem, I would say a better way is to interconnect LAN side of each AP in a sentral point where you run your access control to other parts of the network, ex. by a cheap Linux box running as s router with as many interfaces that you've got APs, or as many zones you need. Maybe I miss something here, but you do not provide much info.

Reply to
Chrisjoy

In the interest of clarity what OS is the palmtop running and is the wireless built in or a flash card. Have you considered RFID tagging the buildings and using that to trigger the change of AP rather than wireless?

Reply to
LR

LR fired this volley in news: snipped-for-privacy@bt.com:

The palmtop runs windows CE, and has built-in wireless. RFID would be an add-on hardware module. It's available, but lacking any other need for RFID on the unit, would be an expensive way to trigger zone swaps.

I can do the automatic switch now, but slowly. I'm just looking for a way to speed up the operation, so it appears more or less 'seamless' to the user.

LLoyd

Reply to
Lloyd E. Sponenburgh

Thanks, my limited past experience with Win Mobile 2003 was that I couldn't find a program that would give me reliable, repeatable WiFi signal levels to do the automatic switching you envisage based on signal level.

Reply to
LR

On Tue, 23 Dec 2008 06:00:00 -0600, "Lloyd E. Sponenburgh" wrote in :

The cost seems pretty minimal to me in your context, but I'd personally avoid something else to maintain that might get out of sync, so I'd stick with SSID.

I doubt that you'll ever be able to get close to that point under Windows -- you should seriously think about switching to Linux -- but if use Windows you must, then you should look into OLE Automation, the official and cleanest way to automate tasks under Windows. (That's something I do, so if you're interested in contracting for such code, let me know.)

Reply to
John Navas

John Navas fired this volley in news: snipped-for-privacy@4ax.com:

I would in a heartbeat. I'm an old ex-'ix developer, myself; started out (on unices) with SCO, then somewhat later with Slackware installed from floppies.

(I know... that dates me; started computing several decades before that... oof!)

So far, I haven't found a Linux variant that will run on these Symbol Technologies handhelds. WinCE runs quite reliably on them, though, absent the bloated code of other Winblows systems.

LLoyd

Reply to
Lloyd E. Sponenburgh

On Tue, 23 Dec 2008 10:56:23 -0600, "Lloyd E. Sponenburgh" wrote in :

I started on the IBM 650! ;)

Bummer!

Reply to
John Navas

snipped-for-privacy@4ax.com:

Yes, it does, if we want to trust your words to be true. I relember the times too, when installing an OS included to search for all the packages needed, make sure they was good to talk with eachother. Anyhow, still you have not explained very well what you want to achieve by your project. Do you want to go into details, if for no other reason so to stimulate my quriosity?

Reply to
Chrisjoy

Chrisjoy fired this volley in news: snipped-for-privacy@e1g2000pra.googlegroups.com:

I did, but you decided to overlook that post in order to continue your tirade.

Besides, I no longer respect your opinions. Even if I thought them to be sound, I would seek others' corroboration of them first.

You back up your positions with bluster, vacuous and childish ripostes and insults, and with no meaningful technical arguments. You seem to disagree with everything, regardless of its technical merit. (c'mon... say you don't...)

I'm not the grammar and spelling police, just an observer who knows that anyone of your "sence" and "quriosity" (sic) shows a decided lack of interest in detail, or worse, ignorance of details. Those are faults which are fatal in the computing field.

LLoyd

Reply to
Lloyd E. Sponenburgh

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