The value of tmnxCpmProtPortOverallRateLimit specifies the per-port
packet arrival rate limit to be applied to all protocol messages
that are to be processed by the CPM.
This object is not supported on SR-1 and ESS-1, where the
value of TIMETRA-CHASSIS-MIB::tmnxChassisType is '5',
and 7710, where the value of TIMETRA-CHASSIS-MIB::tmnxChassisType is
'7' or '9'.