Each entry of the tmnxSubProfSchedOverrideTable describes
ingress/egress scheduler rates which are overridden for the subscriber
profile indicated by tmnxSubProfName. Rows can be created and deleted
by the operator (tmnxSubProfSchedOvrRowStatus). Rows can only be
created for existing schedulers defined in
TIMETRA-QOS-MIB::tVirtualSchedulerTable.