The value of sapIgmpSnpgCfgMcacLagLevel specifies the level id to use
when the value of tmnxMcacLagPortsDown matches the actual number
of ports down in a lag.
Using the value of sapIgmpSnpgCfgMcacLagLevel as an index, the
operational SAP unconstrained bandwidth will be set to
sapIgmpSnpgCfgMcacLevelBW.
By default, for all lag constraints the link level will be set to 1
at row creation.