General Questions About WLC 4400 Cluster

johnnylingo · ‎11-27-2007

I've inherited a couple 4402 Wireless LAN Controllers and am in charge of getting them ship-shape. While I have some general knowledge of wireless, I have not worked with wireless controllers before and have a couple questions I was wondering if anyone could help me with:

1) How can I verify that the primary and secondary controllers are configured for failover without actually performing a test? Both do have AP Failback enabled, but I'm not sure what else to check.

2) They are currently running code 3.2.116.21. Should I stick with 3.2 or plan to move up to 4.X?

Thanks a bunch. I'm slowly working my way through the docs and answers to these would sure speed things up.

Richard Atkin · ‎11-28-2007

Definately move to 4.1 or 4.2 - soooo many bug fixes and feature add's that I can't count.

Failover test is easy to test on a small scale, pick an under-utilised AP and swap the names of the Primary & Secondary Controller over for the AP. Give it a minute and it should have moved its self across. If that worked, then APs will have no trouble falling over in the event of a failure.

johnnylingo · ‎11-28-2007

What's really strange is when I look at the AP configuration, the hostnames for the primary, secondary, and tertiary controllers is blank. I can't figure out how they were able to home to the primary controller in the first place. Maybe DHCP option 43 or some type of broadcast? All of the APs and Controller management IPs are on a single VLAN.

johnnylingo · ‎11-28-2007

To answer my own question, I'm guessing that it pulls the controller hostname via LWAPP, because when it boots I see an LWAPP request to 255.255.255.255 port 12223 although I'm not sure who is answering and with what.

Richard Atkin · ‎11-29-2007

If they're all on the same VLAN, the APs will discover every WLC through a "L3 Broadcast". "L3" refers to the LWAPP type, and "Broadcast" refers to a normal L2 IP broadcast.

The broadcast will hit every WLC, and to cut a long story short, the AP will join the WLC with "most spare capacity". In this situation, no DNS or DHCP or OTAP provisioning is required.

Regards,

Richard.