WLAN SSID not visible for certain clients

Unanswered Question
Oct 8th, 2008

I am experiencing strange situation at one installation where I installed unifies wireless network with multiple branches. All the branch wireless APs are registered with central WLC- ( WiSM on 6500).


Client A can see WLANs configured, and can connect succesfully at location X.

When the same client (A) moves to locaiton Y he cannot see any WLAN SSIDs there, but some other client can see those.

It is very difficult to see whether this is a client problem or AP issue.

Any ideas ?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Scott Fella Wed, 10/08/2008 - 03:41

Are you running the ap's in h-reap or local? Also what are the devices having issues... laptops or scanners..etc? You need to try to isolate the issue to either a particualr device, driver or ap configuration. You are not using wlan override or are you? Need more info on how you setup the wireless and what devices are using and having issues on the wirleess.

nkariyawasam Wed, 10/08/2008 - 19:43


I am running H-reap mode. It cannot be identified as a device issue, becase, as I explained in my post, the SAME client (A, is a laptop computer) is behaving differantly in two differant locations. ( of course, APs in both locations are registered with the central WLCs in WiSM, but I coudn't really isolate whether the two APs are belongs to the same controller inside the WiSM card.).

Scott Fella Wed, 10/08/2008 - 20:15

Can you post your show run-config of the two WLC's in the WiSM and specify which ssid you are having issues with.

on the 6500 get the mac address of the client from the arp table when in location X. do a show "show mac-address-table address xxxx.xxxx.xxx for the client and keep note of if it learns it from the AP in the Y location or A location. If the mac table learns the mac from a different port it will expire the coorisponding arp entry in the arp table . look at the arp table and see if there is an old age time or a zero'd age time.

let me know what its doing

either this

If the arp is zero'd out and relearned in the mac table by way of the ap in location Y


the arp entry is still aging and the mac table still show the entry being learned from the ap in location X.

also check the event viewer of the machine and see if there are dhcp errors, like getting a 169.254.x.x address

run an extended ping from the 6500 to the device

run a ping -t -l 1500 x.x.x.x from the device to the 6500 while you are roaming from X to Y

turn on client side debugging for the supplicant

try doing a 802.11 debug on the AP


This Discussion