We have a wireless deployment that spans multiple sites, the WLC's are located in Central Data Centre and we provide four SSIDs, one for computers belonging to our administrative users, one for ipads and smartphones belonging to administrative users, one for computers belonging to students and one for guests. Authorization for the networks is done in different ways, guests use webportal and the others certificates. IP addresses are allocated from our DHCP.
AP's are registered to our 4 WLC's and we use NCS to manage them. Ap’s are LWAPP 1142.
The problem is as follows:
Users authenticate fine, they're passing traffic, but after a period of time they suddenly can't get internet access anymore. When looking in the NCS they are not disconnected from the AP itself and the AP looks ok. The client retains all of its DHCP settings. If you try to ping defgw from a client you might lose all packets or 80-90% of them. When we run linktest from NCS we don’t get any connection to the clients. When using spectrum expert we can’t see any obvious problems.
If users disconnect and reconnect they might get connected to another AP nearby and then it works. If they get connected to the same AP the problem continues for a while, then it starts to work again.
I’ve seen and can confirm this problem in two schools, in classrooms. At the first site all computers, connected to different SSIDs, both 2.4 GHz and 5Ghz, lost connection at the same time. At the second site, half of the students lost connection at the same time. In both cases you lost all packets or 80-90% of them when pinging defgw. No problem to ping the same defgw from wired network or to ping IP of AP.
The software version that we're using on all the 5508 controllers is 7.3.101.0.
Suggestions how to troubleshoot would be appreciated. Are there any debugs that I can run to show what's happening to the client/AP? How can I find out where the packets get lost?
Thanks
Tomas
