MAC FIB size limits is a required MAC table management feature for each instance of a SAP or spoke-SDP within a particular VPLS service instance. It allows users to specify the maximum number of MAC FIB entries that are learned locally for a SAP or remotely for a spoke-SDP. If the configured limit is reached, then no new addresses are learned from the SAP or spoke-SDP until at least one FIB entry is aged out or cleared, as follows:
When the limit is reached on a SAP, packets with unknown source MAC addresses are still forwarded (this default behavior can be changed by configuration). By default, if the destination MAC address is known, it is forwarded based on the FIB, and if the destination MAC address is unknown, it is flooded. Alternatively, if discard unknown is enabled at the VPLS service level, unknown destination MAC addresses are discarded.
The log event SAP MAC limit reached is generated when the limit is reached. When the condition is cleared, the log event SAP MAC Limit Reached Condition Cleared is generated.
Disable learning at the VPLS service level allows users to disable the dynamic learning function on the service. Disable Learning is supported at the SAP and spoke-SDP level as well.
Disable aging allows users to turn off aging for learned MAC addresses. It is supported at the VPLS service level, SAP level and spoke-SDP level.