Intermittent issues with DHCP and a AP541N

[nathan.a.reeves]

Installed 4 AP541N units in a client site and they've now come back with reports of issues with the setup.  I went out there today to take a look and the issue is primarily that randomly during the day, clients will loose access to DHCP.  The client authenticates fine (we see success logs in the Windows 2008 RADIUS event logs) but doesn't manage to get an ip address.

To sum up the things with the current setup:

- Running version 2.0 Code on the AP541N's.

- Using Windows 2008 for NPS (RADIUS) and DHCP.

- Cisco Catalyst Switching in the back end.

Things tend to work fine in the morning.  It's as the site hits midday that we start seeing issues.

In looking at the issue I've come across a number of posts in regards to issues with DHCP and these units.  One item that was suggested to switch off Mutlicast / Broadcast limiting on the Advanced Settings.  What's weird with this is that if I do disable this option, RADIUS authentication stops working entirely.  Switch limiting back on and RADIUS works again.  I've confirmed this with Network Monitor running on the RADIUS Server.

Anyone got any suggestions for this issue.  I'm especially interested to know what the deal is with RADIUS stopping when Broadcast limiting is disabled.

TIA

Nathan

[nathan.a.reeves]

Just as a followup in case anyone comes across this post.

I ended up upgrading to the 2.0.1 beta code but in this case the issue wasn't resolved.  As I looked further on the customers network I realised that the txload on the connected switchports (using Cisco 2960 switches) was higher than I'd expect.  Ended up tracing the load back to a port which I disabled.  The port was pushing out about 12,000pps.  Once we shut this port down (customer is still tracing the cabling) wireless started to hand out dhcp.

Waiting for a couple of days to class this one as fixed but just as a pointer to others who may see issues on these AP's, just check your network doesn't have high broadcasts (or what I'm guessing here is a loop).

Cheers

[jasbryan]

Nathan,

Thanks for the reposting of your solution - !

cheers,

Jasbryan