wifi problems

[a]

I have around 20 pdas running at an event that need to connect
wirelessly to a server. We use the ipaq 2700 series. There may be
other wifi connections in the area. The connections for us are
problematic, as sometimes it will take going through 4 or 5 pdas to
find one that can actually connect to the server. They all have the
same software. On the ones that don't connect, a re-boot with the
stylus usually fixes it. I am simply turning on the WiFi with ipaq's
radio function. If we go into the settings, the wifi will show as
connected, but still not be able to 'connect' to the server to
retrieve/check for data.

Even at the office, the wifi would show as green, and for 10 minutes
we couldn't get the pda to get data from the server, until we actually
stopped and started the sql server. Weird. But since some can connect
in the field it seems to be a different problem.

Can anyone provide insight into this problem?

 

[Paul G. Tobey [eMVP]]

Are the devices configured for DHCP-assignment of IP addresses? Is the DHCP
server under your control? Do it and the devices agree about what IP
addresses have been assigned to what devices? Are there enough free
DHCP-assignable addresses in the server's list to allow it to assign that
many addresses (given any reservations that might be in place, along with
any other devices that have already been assigned addresses -- other
computers on the network)?

Paul T.

 

[a]

Yes to all that.

Are the devices configured for DHCP-assignment of IP addresses? Is the DHCP
server under your control? Do it and the devices agree about what IP
addresses have been assigned to what devices? Are there enough free
DHCP-assignable addresses in the server's list to allow it to assign that
many addresses (given any reservations that might be in place, along with
any other devices that have already been assigned addresses -- other
computers on the network)?

Paul T.

 

[Paul G. Tobey [eMVP]]

Can the devices all ping the server? That is, I'm trying to distinguish
between network connectivity and application connectivity. My suspicion is
that something about your "server" application or your software on the
device is broken. I doubt that anyone has done precisely what you're doing
with that exact hardware, but we don't generally have any problems where
some fraction of a set of devices can't connect to a server. What sort of
server application are we talking about? SQL Server? You have enough
client access licenses installed?

Paul T.

 

[a]

Yes they can ping the server, which runs sql2k. There are also desktop
pcs connecting to the server (not wirelessly) which have no problems.
Access licenses is not an issue.

There is no server application, other than the database service. The
pda's simply do a record lookup with the database connection, and it
is here while trying to connect to the database that the troubles are
at.

 

[Paul G. Tobey [eMVP]]

So, this has nothing to do with WiFi, then, right? The network connectivity
is not in question and it's the database connectivity that's the problem?

Tell us some more about the database connection or show us the code that is
failing with the 'unable to connect'. Give us the information on the server
machine, as well as version information on the SQL Server 2000, etc. Also,
we'll need to know what version of .NET CF you're using and what version of
SQLCE/SQL Mobile/whatever you have installed on the devices.

Paul T.

 

[a]

Thanks. I'll get looking into that, but now I am wondering if the
pda's are server-assigned ip's or static. I need to talk to someone
about this to find out but could that be the problem if they are
server-assigned?

 

[Paul G. Tobey [eMVP]]

"Yes to all that.", previously? THE DEVICES CAN ALL PING THE SERVER?! Now
you've got me questioning everything that you've said so far! Get real
answers to all my questions and report back the actual answers and, what the
heck, the actual IP addresses, just so I can feel confident that you
actually have checked and gotten the real answers...

Paul T.

 

[a]

I checked and the pda's have static ip's, like I thought. Just wanted
to make sure. The pda ip's are 10.0.7.x

 

[a]

as a follow-up to anyone interested, they moved the access point
further away from the pda's and this appears to have fixed the
problem.

 

[Paul G. Tobey [eMVP]]

OK, that sounds like a radio interference problem. I've never had that;
very odd.

Paul T.

 

[zedtech]

How close where the PDAs to the AP?

 

[a]

i wasn't there myself, but apparently they we're right beside it.