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Robert Giordano

Multicast works for a day and then stops

I'm running multicast in unicast mode on our WLC because I can't enable PIM on wired side yet for a couple reasons.  It works consistently on 3 out of 6 WLAN's.  And the weird thing is the other 3 WLAN's will work for a day, and when I come in the next day, multicast traffic has stopped flowing.  I have verified this through IGMP snooping, using a bonjour browser, testing airplay, and using packet capture on a wireless NIC.  2 of the WLAN's are configured almost identically, but one works consistently day after day, and the other only works for a day after resetting the wlan.  I have been coming in the morning and changing a single setting back and forth just to reset the WLAN so it will work for the rest of the day.  I'm just writing this to see if someone can think of why it would work fine for the shole day and then stop working by the next morning.  It's not an IGMP timeout setting, because it works for much longer than the timeout and behaves the same way even without IGMP snooping on.  It started doing this after upgrading to  We have very little amount of multicast traffic on wireless, and low channel utilization.  It does the same exact thing whether 802.11a or 802.11g so I don't think it has to do with data rates.  When I have IGMP snooping on, and on the WLAN's where it's not working, the controller will see the multicast group join message from the client, but the client doesn't see the IGMP query from the controller.  It shouldn't be wired config related since it's unicast mode.  I've tried with and without broadcasting enabled.  Any ideas?

Robert Giordano

Okay, so I discovered two things, but I still don't know what caused this problem.  When I was running I had increased my EAP-Broadcast key interval to 86400 due to a bug.  This seems to be related to the fact that on the wlan's where multicast was not working, it stopped by the next day.  When I backed this interval down to 3600 the multicast stopped working after an hour instead of a day.  So that's why I believe it was somewhat related to the broadcast key, since that key is used for multicast. 

What I realized is that multicast was working on all the wlan's on all AP's that had been rebooted since the controller upgrade (They had been rebooted due to a switch losing power).  This is weird because all the AP's were rebooted when they received their own software upgrade, so I don't know why they would have needed to be rebooted again.  Anyway, I rebooted a few more AP's and multicast works properly on all wlan's on those.  I'm just replying to my own thread here in case someone has a similar problem after upgrading your controller - try rebooting all your access points again.  Or maybe reboot after changing EAP-Broadcast Key interval.

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