Hi all,
Debugging the STP state sync events on a Cisco 3560 running 12.2(55)SE1 through the following command:
debug spanning-tree synchronization
Every 2 minutes I get the following messages:
May 6 10:13:14: STP sync: Send ALL port data to all other switches...
May 6 10:13:14: STP sync: NULL sync_data -- nothing to send
May 6 10:15:14: STP sync: Send ALL port data to all other switches...
May 6 10:15:14: STP sync: NULL sync_data -- nothing to send
May 6 10:17:14: STP sync: Send ALL port data to all other switches...
May 6 10:17:14: STP sync: NULL sync_data -- nothing to send
May 6 10:19:14: STP sync: Send ALL port data to all other switches...
May 6 10:19:14: STP sync: NULL sync_data -- nothing to send
May 6 10:21:14: STP sync: Send ALL port data to all other switches...
May 6 10:21:14: STP sync: NULL sync_data -- nothing to send
May 6 10:23:14: STP sync: Send ALL port data to all other switches...
May 6 10:23:14: STP sync: NULL sync_data -- nothing to send
May 6 10:25:14: STP sync: Send ALL port data to all other switches...
May 6 10:25:14: STP sync: NULL sync_data -- nothing to send
Could anyone explain what does "Send ALL port data to all other switches..." mean? Can I disable the STP synchronization protocol?
As I'm running IGMP snooping on that switch, every time I receive the messages above, these are interpretated as a TCN spanning-tree event and the multicast traffic is flooded to all the ports. In order to avoid that, I had to disable the multicast flooding on the uplink interface:
no ip igmp snooping tcn flood
Is it a common procedure or just a bug?
Thanks and regards,
Vincenzo
