Wireless LAN conundrum...

ColmOT [MSFT]

I’ve got a wireless network at home (802.11b). There are 3 nodes: 2 desktops and a laptop.

One desktop (PC1) is downstairs with a USB wireless NIC attached. This desktop is also a DHCP server as configured by the ICS service. The other desktop (PC2) is upstairs with a similar USB wireless NIC attached. The laptop is omnipotent!

I’ve configured the connections on each machine with the same settings (ESSID, channel, WEP (disabled), preamble type etc…).

If I use my laptop (PC3) in another room downstairs, and attempt to connect to PC1, it works fine and I can get an IP address from that machine and can access the shares etc on that machine.

If I use my desktop (PC2) upstairs, I cannot access the PC downstairs. I get an APIPA IP address.

If I use the laptop upstairs, and have it beside PC2, I cannot get an IP address and can’t access PC1.

In other areas upstairs I can get an IP address and connect to PC1.

When PC2 & PC3 are in the same room (where they cannot detect PC1), they can ping each other with no problem.

Here is the weird thing though, both PCs upstairs state that they have an excellent signal with PC1, and they can all detect the network (through the Windows XP ‘Show available wireless networks’ option. If I change the ESSID name on PC1, and then go to PC2 and scan for available networks, both PC2 & PC3 detect the new ESSID name, even though they cannot get an IP address from PC1.

To make things even more weird, there is ‘intermittent’ connectivity between PC1 & PC2.

The distance between the wireless NIC on PC1 and the wireless NIC on PC2 is no greater than 7-10 meters.

It looks like PC2 & PC3 are out of range of PC1 when they are up stairs, but how can they detect the ESSID network name if that’s the case?

Does anyone have any idea what might be going wrong here, or have I missed something totally obvious?

Thanks.

GlennaMaddy

Is there a firewall between the two rooms, check this with your builder!

ColmOT [MSFT]

I'm beginning to think that there is alead wall between the rooms alright!! :-)

But seriously, this has me totally stumped, as I've tried everything I know...and I like to think I know a bit about wireless networking!!!

crowbar

are all your cards set to peer-to-peer or ad hoc mode? i've never really played around with peer-to-peer, but maybe there are limitations with ad hoc mode and the number of pcs you can talk to. (i have only ever played with networks where there is an access point acting as the network traffic cop.)

BigEejit

I think you answered your own question there ColmOT ... if the laptop connects elsewhere but not beside the problem machine then its obvious that there is an inteference issue ... some newer houses have had foil lined plasterboard that blocks signals ... you may even have a big lump of metal in the wall between them (I-beam acting as a support or joist) ... if its a USB wireless nic try moving it around (as far left and right as it will reach), try moving the upstairs one as well (moving in the same direction as the other one at the same time) .....

I think that you will pick up the essid easily because it is transmitted in the clear .... the rest of the packet may be distorted too much to use (pure guess )

ColmOT [MSFT]

Heya - It's started working now...and I didn't change a thing!! I just booted the PC and the wlan hooked itself up....

This is very bizarre!! I'm curious how long it'll last....

The Clown Man

Yea if you are connecting them peer-to-peer I would say that you might get a signal through one or two walls. Is it possible that there is steel in your upstairs floor?

I'd say that you have three options;

1. Move the PC's round a bit because there might be some points with better reception than others (you'd be surprised at what a difference a few feet might make). Put the USB NIC as high as you can get it. Unfortunately though, your laptop will doubtful be able to connect upstairs.

2. Buy an access point and you will be able to connect anywhere in the house. €80-€120.

3. Buy one of these antennea that increases signal strength for the downstairs computer. I have only heard about these so I don' know how well they work but if they do what they're supposed to do then it should work.

babypink

personally my experience of ad-hoc wlans has been that with 2 pc's they work fine but once you start trying to get 3 pc's to talk to each other the whole things eems to just go a bit on the shady side. I would go out and get yourself an access point, prefereably one with a hub built into it so if you decide to broadband in the future just ethernet the broadband modem into the hub.

Access points are well worth th bit o' cash

Capt'n Midnight

Originally posted by GlennaMaddy
Is there a firewall between the two rooms, check this with your builder!

Maybe your plasterboard is foil lined

Yeah I've not heard of anyone getting more than two AdHoc working reliably at the same time.