Dear Community,
I'd like to ask about device behavior when it reports every second:
%-SLOT1-5-BCM_L2_LEARN_DISABLE: MAC Learning Disabled unit=0
%-SLOT1-5-BCM_L2_LEARN_ENABLE: MAC Learning Enabled unit=0
Does this mean that when the Mac learning is turned off, the device transmits traffic to all ports?
Described event applies to the Nexus C9372PX 7.0(3)I4(7) acting as Cisco Nexus Data Broker. In my case the problem occured after I started collecting data C9372PX e1/1 and e1/2. Both (e1/1,2) interfaces are connected to the pair of N7700 (working in one vpc domain). Tt is possible that same MAC becomes visible across e1/1 and e1/2.
Similar situation has been described in CSCuy65463:
When using Nexus 9K switches (Nexus 9300 and Nexus 9500 with T2 line cards) for Tap aggregation, there is a potential that same MAC becomes visible across different ports as customers tap different points in their network. In Nexus 3K today we have the ability to disable the MAC learning globally but on Nexus 9K switches we do not have a similar command.
It is highly critical to have this command on Nexus 9K because when used with Tap aggression, undesired MAC move syslog messages are generated that fills up the syslog file.
Conditions:
Workaround:
None.
My question is, does the described situation apply only to writing a large number of messages to the log or is there a potential danger that the traffic is forwarded to all ports?
Regards
Piotr
