This attribute indicates the current backplane operating mode. On
the fabric-based shelf:
noFabric - No fabric is in service now.
singleFabricX - The shelf is running on fabric X only.
singleFabricY - The shelf is running on fabric Y only.
dualFabric - The shelf is running on fabric X and fabric Y.
On the bus-based shelf:
noBus - No bus is in service now.
singleBusX - The shelf is running on bus X only.
singleBusY - The shelf is running on bus Y only.
dualBus - The shelf is running on bus X and bus Y