Re: Aironet 1200 AP and Dell Notebooks

KingMooCow · ‎12-22-2003

My company provides wi-fi internet access in Hotels across the country... Recently, we have switched from using Enterasys AP's to Cisco 1200 AP's. In nearly all the sites that we've started using the Cisco AP's, we're having problems with Dell Laptop Users... Are there any know issues with Dell Laptops using their Internal Intel or TrueMobile cards? This is becoming a very frustrating issue for us and our customers. Any insight into this issue would be greatly appreciated.

rmiles · ‎12-28-2003

Could you give some details on what the problems are?

--Ryan

KingMooCow · ‎12-28-2003

The Dell users-- seeming no matter what CARD they're using, if it's a b/g card with one of out cisco AP's, it won't pass traffic. When we attempt to ping the dell, the ping command hangs. But if the user disables/reenables the NIC, ONE packet will slip through, so we know that connectivity is happening, but something is blocking it. The user will attain an IP address, and will show up in the ARP table on the server, but can't load any web pages or recieve any pings... I don't know what's wrong here. It may be a issue with the dell going backwards compatible for G cards, but we can't figure out HOW that would be the case.

shh5455 · ‎12-31-2003

Are you using any authentication / encryption?

KingMooCow · ‎12-31-2003

none

rmiles · ‎12-31-2003

So, you just have a single SSID defined with no encryption/authentication? Do you see the client association on the access point? Have you tried different client adapters?

KingMooCow · ‎12-31-2003

Yes, single SSID, no Enc. I dont know how to check assosications on the ap, but I'd like to know... Tried different adapters, none that we've seen have worked with the Dell's, but work fine in other brands of laptops...

rmiles · ‎01-02-2004

You can see the association table by accessing the AP's webpage. I guess this would at least tell you if the access point shows the client as being associated to the AP.

You say that the client receives a DHCP address?

Does it retain this address or does it lose it's address at some point?

Is this on one subnet or multiple subnets?

Can you ping from the client to the AP?

Are the AP1200's running IOS or VxWorks? What version of IOS or VxWorks? (If you're not using IOS I would suggest that you upgrade)

If it's IOS can you ping from the AP to the client?

Do you have a Cisco NIC to test in the Dells?

jdroten · ‎01-03-2004

The APs are on remote networks behind firewalls. This makes it kinda difficult to view the webpage interface. I suppose I could setup some ipsec tunnels to remedy that. Any way to view the assosiactions via command line(IOS).

Client does recieve a DHCP address. The client does not loose the address and remains active in the arp table on the gateway/firewall(OpenBSD box). However we can not ping the guest at all. If the guest disable/enables thier interface or reboots we see one packet on a restart of networking(on thier PC) and then nothing again.

Single subnet /24

We have comminucation such as ping from client to AP blocked.

APs are in fact running IOS. (C1200-K9W7-M), Version 12.2(11)JA1

Tier 2 does not have access to ping clients from APs, so this step has not been done.

No cisco nics to give to the clients having troubles, however my Aironet 350 series "b" card works fine in the lab. But again, I dont think that matters as I think this might be something specfic with "g" cards.

Hope that helps.

rmiles · ‎01-03-2004

Other clients (non-Dells) are working ok? I guess at that point it would point to the client card being the problem. I have not dealt with any g hardware yet, so I am not sure what could be done there (settings, drivers, etc). If it's only a Dell NIC issue have you contacted Dell or perhaps opened a Cisco TAC case?

And to view client associations via telnet the command is "sh dot11 associations". Also, you may try upgrading to the latest IOS on at least one AP. With each IOS release problems are resolved which may include compatibility with certain client adapters. One of the latest IOS revisions resolved a problem with a Compaq W200, which we use and it now works fine due to new IOS.

Could you post the AP's config (write terminal)?

rmiles · ‎01-03-2004

Also, have you made sure you're using the latest drivers for the G clients from the vendor?

See this link: http://www.cisco.com/en/US/customer/products/hw/wireless/ps430/prod_release_note09186a00801d725c.html#67475

KingMooCow · ‎01-05-2004

Yes, we've tried newer drivers... But its been with many different brands of cards... Microsoft, Intel and Dell to name a few.

We have a potential answer that we need to research a little more -- this was taken from a Dell forum:

"The preamble issue is the problem, however you do not have to change you preamble setting on the AP. This can cause issue for others that are currently working.

All you have to do, is go into the configure option for the TM 1300 card and change the preamble or (PLCP Header) to "Long" instead of auto.

The problem is that by default, most wireless APs use short by default. The TM 1300 appearantly has trouble deciding which preamble to use "short" or "long". Since you cannot change the setting to "Short", you can change it to "long" and then the Cisco AP should detect that your card is not short compliant and then send the preambles automatically using long."

In the only case we've tested with this theory, its been a success, but we're not sure if this will resolve all cards issues.