Controllerless Networks

We are facing a strange problem for last three months. We run a wireless network at our office- 350+ employees and visitors - 33 IAPs - a mix of Instant AP 335s and 325s running code 6.5.4.3-6.5.4.3_61959. Two SSIDs exist - 802.1x for employees and WebAuth for visitors and guests. A few times in a month on business days in between 0900 HRS and 1100 HRS when we have a number of meetings going on around the office the wireless drops. The symptom follows the same pattern - days when we have a number of visitors and occurs during mornings. A re-election of the master IAP takes place which results in complete outage over the wireless network till the time new master doesn't get elected. During the time period that the election is complete, we can ping none of the IAPs. We have performed a health check on ethernet cables but have found no CRC errors or cable issues. Our switching infrastructure is 10G. We have checked the logs from APs that have remained Master but are failing to formulate a direction.     

The #1 reason for this is having your Instant management VLAN on the same VLAN as alot of wired broadcast traffic.  If you can, create a new management VLAN for your Instant APs and put them on that new VLAN to protect them from excessive wired broadcasts,

We have separate management and client vlans. Management VLAN dhcp lease time is 8 hours. 

Correction -  8 days.

Right, but is the management vlan shared with other wired traffic that is not related to the IAPs?

No. Only Aruba IAPs exist in Aruba Management VLAN. Other network devices have their own management vlan. 

Okay.  Are you using broadcast filtering on all of your SSIDs?

Broadcast Filtering is disabled for all SSIDs.

It should be enabled on all SSIDs, otherwise you will have performance issues.  Try it.