This object is to enable or disable the limit of number
of MAC addresses function globally.
MAC limit function is to try to control the number of MAC
addresses for each VLAN or interface or interface-VLAN pair in
the forwarding tables for a network device. It is possible that
one VLAN or one interface or interface-VLAN pair can exhaust
all available MAC entries because of Denial-of-Service
and cause users' traffic on the other VLANS or interfaces flooded.
To prevent this situation, the MAC limit for each VLAN or interface
or interface-VLAN pair is needed. The major function of this
feature is to protect the layer 2 forwarding table.