We are a  Medium sized business ( Mostly running Win 2000 and Win XP sp2) .
We have deployed a combination of Linksys Wireless cards WMP54G ( PCI
Adapter) and WUSB54G ( USB) Cards on our user machines .

Drivers for the above cards are upto date .

We use CISCO Wireless Controllers , 4400 Series , With that we have deployed
11 AP thru out our office

NEtwork mode - Infrastructure
Security WPA-Personal  (TKIP)
Our SSID are in NON Broadcast mode
NO MAC filtering

With the above said , ever since we have deployed wireless to our corporate
users , we have been experiencing intermittent connectivity drop issues  the
following messages are logged in the event manager

Your computer was not able to renew its address from the network (from the
DHCP Server) for the Network Card with network address 001217920252.  The
following error occured:
The semaphore timeout period has expired. . Your computer will continue to
try and obtain an address on its own from the network address (DHCP) server.

The system detected that network adapter Linksys Wireless-G PCI Adapter was
connected to the network, and has initiated normal operation over the network
adapter.

Your computer was not able to renew its address from the network (from the
DHCP Server) for the Network Card with network address 001217920252.  The
following error occured:
The semaphore timeout period has expired. . Your computer will continue to
try and obtain an address on its own from the network address (DHCP) server.

The system detected that network adapter Linksys Wireless-G PCI Adapter was
connected to the network, and has initiated normal operation over the network
adapter.

The server could not bind to the transport
\Device\NetBT_Tcpip_{BEF2EDB1-141C-47B2-BAC1-8033C1B37F9A}.

Your computer was unable to automatically configure the IP parameters for
the Network Card with the network address 001217920252.  The following error
occurred during configuration: The parameter is incorrect. .

The browser has forced an election on network
\Device\NetBT_Tcpip_{BEF2EDB1-141C-47B2-BAC1-8033C1B37F9A} because a master
browser was stopped.


We have tried all possible means to debug the issue , but no resolution as
yet .

Any insights would be helpful.

Thanks . Navin Musalgavkar

Two things:

1) Did you check that the channel your router uses isn't in use nearby or
that any other wi-fi at all is in use? BTW, you mentioned no MAC filtering.
I would filter were I you.

2) Interference sources. Checked for them?

Now assuming you have checked both and no problems arise from those, then
welcome to wi-fi. Intermitted drops are actually quite normal.

One last thing - check out what sort of stuff is in the walls. The aluminium
coated stuff they put in walls really creates a large problem with wi-fi. So
do high voltage power lines and hospitals nearby.

Show quote Hide quote #1:- We use Channel 1 , 6 and 11 . Have 3 floors in the building , so SSID
for each floor and with a specific channel

For example   WIFI-SECURE-FLR1 - Uses channel 1 ( has 3 AP's)

For example   WIFI-SECURE-FLR2 - Uses channel 3 ( has 4 AP's)

For example   WIFI-SECURE-FLR3 - Uses channel 4 ( has 4 AP's)


We would try mac Filtering and post a reply back , will take us days to get
this info as we have more than 400 ( Combination of desktops and laptops ) .
This connectivity drop problem as of now is restricted to the desktop users
using the PCI and USB adapters.

#2 :- have 2 microwaves in the building , but these are restricted to the
Kitchen areas which are far off from the AP .
Have used spectrum analyzer to check out the AP distribution patterns .  ALL
AP's have a distance of atleast 25 feet between them , and their signals
overlap on the edge of the broadcast spectrum .


#3:- As any building the usual stuff is present , we have checked it for any
attenuation issues , none found so far .


To solve this issue we have been investigating the following

a> Are our AP's Overloaded at some certian intervals

b> We have 11 AP's thru out these 3 floors , Are they capable enough to
handle 400 + users . What should be a the # of people/ Machines per AP

c> is there a radio saturation caused by these AP's

d> As of now we only use the b and g radio's , Should we try the  A radios ,
All our laptops do support a ?

e> Should we try creating wireless zones in short assiging a particular AP
to a fixed set of people ?.


To test our theories out we did set a Linksys wireless Access point , WPA
etc. etc.
and configured about 6 -7 people to use only that AP and nothing else .
During this test we found that those desktops ( PCI and USB) did not drop
their connections .But the only problem we discovered during this test was
the Linksys router interfered with our other AP's in the building and caused
a dead spot .Perhaps the the layout for this was an issue and we moved it to
a farthest spot in our building Problem disappeared Thats how we started
going the zone route ( #e)  .

let me know if more details are needed .

If so, you need smart bridging.

What is the machinery used?

Possible.

They should but of note, today I was exposed to a wi-fi network to be set up
amongst only a few users in one building, separated from any others. It
should have been an easy install but it took longer than expected. The
D-Link router worked amongst the users with cards for their laptops but it
didnt register at all on my PDA. My PDA only does A and B and the router was
set to auto and said it would do any speed. It clearly didnt. So, though I
reported it as a faulty unit, the company seemed disinclined to do anything
about it as "it works for them doesnt it?". I had to answer "for now".

That would be my move, yes. It depends on the equipment you are using of
course and you can smart bridge them as needed.

Show quoteHide quoteOne thing you haven't considered - or at least it wasn't mentioned in case
you have thought about it - is using better aerials. You can buy stuff
designed to work in particular ways and people even home-make stuff like
that. You may consider this.

Oh and one more thing - you may consider dropping the output power on all
APs to 50% and see what you get. If they reach the users but not each other,
the result may be what you are looking for.

Tried all the steps listed above , No Success so far .
Now getting CISCO and  Linksys into a meeting to hash this out .
Will post more details later

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