The value of tmnxCpmProtExcdSapEcmMac specifies a source MAC
address. The Eth-CFM PDU stream matching the MAC address (and
matching the other index values of this table) has exceeded its
Eth-CFM rate limit.
The manager must provide the all-zero MAC address to get a row for a
stream which is Eth-CFM rate limited using the
'ethCfmMonitorAggregate(1)' option of the
sapCpmProtEthCfmMonitorFlags object.