Wireless disconnect, dhcp doesn't answer and other strange things.

At our company we have a system of about 10 wireless APs. I have
configured it as follows:

Common SSID (allows roaming)
Common WEP-key
Channel seperation of at least 2 steps between neighboring APs

Win2003 server running the DHCP, subnet 192.168.0.x

About 150 client computers running winXP

Network printers and so on ..


Now to my problem.
If only a couple of people are up and running, the system works great,
but when the sytem gets loaded, the sh**t really hits the fan!

All kinds of trouble starts to happen, the most prominent, DHCP stops
answering - for some, not all mind you. The connection to the AP is
unstable at best and when it is stable, the connection to the LAN is
not. Suddenly your'e stuck with a good ol' 169.X.X.X all the while the
ap connection says "good".

Any ideas??

"blah" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> At our company we have a system of about 10 wireless APs. I have
> configured it as follows:
>
> Common SSID (allows roaming)
> Common WEP-key
> Channel seperation of at least 2 steps between neighboring APs
>
> Win2003 server running the DHCP, subnet 192.168.0.x
>
> About 150 client computers running winXP
>
> Network printers and so on ..
>
>
> Now to my problem.
> If only a couple of people are up and running, the system works great,
> but when the sytem gets loaded, the sh**t really hits the fan!
>
> All kinds of trouble starts to happen, the most prominent, DHCP stops
> answering - for some, not all mind you. The connection to the AP is
> unstable at best and when it is stable, the connection to the LAN is
> not. Suddenly your'e stuck with a good ol' 169.X.X.X all the while the
> ap connection says "good".
>
> Any ideas??

Are all 10 APs and the DHCP server connected to the same VLAN (or switch, if
you're not using VLANs)? What brand and model of AP are you using?

Are the APs all in one open space, or are there walls involved? A
separation of at least 3 channels is recommended.

The usual culprit when the association to the AP is good, but traffic won't
flow, is that the encryption keys aren't set correctly. This happens
because Open Authentication requires no keys and uses no encryption, so
association is successful even when the keys are wrong. Try verifying the
keys by connecting one laptop sequentially to each of the 10 APs. Make sure
that the laptop is associated to the desired AP, and then PING the Default
Gateway address.

Examine the DHCP server's log. Make sure the problem isn't there. You
might even want to run Network Monitor on the DHCP server and sniff the DHCP
traffic.

HTH

Ron Bandes, CCNP, CTT+, etc.

"Ron Bandes" <RunderscoreBandes @yah00.com> wrote in message news:<1xY8d.9892$(E-Mail Removed) et>...
> "blah" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed) om...
> > At our company we have a system of about 10 wireless APs. I have
> > configured it as follows:
> >
> > Common SSID (allows roaming)
> > Common WEP-key
> > Channel seperation of at least 2 steps between neighboring APs
> >
> > Win2003 server running the DHCP, subnet 192.168.0.x
> >
> > About 150 client computers running winXP
> >
> > Network printers and so on ..
> >
> >
> > Now to my problem.
> > If only a couple of people are up and running, the system works great,
> > but when the sytem gets loaded, the sh**t really hits the fan!
> >
> > All kinds of trouble starts to happen, the most prominent, DHCP stops
> > answering - for some, not all mind you. The connection to the AP is
> > unstable at best and when it is stable, the connection to the LAN is
> > not. Suddenly your'e stuck with a good ol' 169.X.X.X all the while the
> > ap connection says "good".
> >
> > Any ideas??
>
> Are all 10 APs and the DHCP server connected to the same VLAN (or switch, if
> you're not using VLANs)? What brand and model of AP are you using?

All 10 APs are connected to the same switch, no VLANs involved.
I'm using D-LINK DWL-2100.

>
> Are the APs all in one open space, or are there walls involved? A
> separation of at least 3 channels is recommended.

Walls are involved, its acutally a school and every classroom has got
it's own AP. Perhaps there is one problem, to many APs in a small
area? But then I'm worried about crowding one AP if i take some down.
How many users on an AP is recommended? (Classroom applications manly)


>
> The usual culprit when the association to the AP is good, but traffic won't
> flow, is that the encryption keys aren't set correctly. This happens
> because Open Authentication requires no keys and uses no encryption, so
> association is successful even when the keys are wrong. Try verifying the
> keys by connecting one laptop sequentially to each of the 10 APs. Make sure
> that the laptop is associated to the desired AP, and then PING the Default
> Gateway address.

Has done, and will do again. Thanks fot the tip. How about shared key?
Any better?

>
> Examine the DHCP server's log. Make sure the problem isn't there. You
> might even want to run Network Monitor on the DHCP server and sniff the DHCP
> traffic.

Will do!

>
> HTH
>
> Ron Bandes, CCNP, CTT+, etc.


Thanks for the input!!