Data ONTAP supports two storage connection architectures: serial-attached SCSI (SAS) and Fibre Channel (FC). The FC connection architecture supports three topologies: arbitrated loop, switched, and point-to-point.
SAS-connected disk shelves are connected to the controller on a daisy chain called a stack. FC-connected disk shelves are connected to the controller on a loop. You cannot combine different connection architectures in the same loop or stack.
For the MetroCluster configuration, the FC and SAS connection architectures can be combined in a bridged connection, with FC on the controller side and SAS on the shelf side. The bridged connection can be used in either a direct-attached or switched topology. For more information, see Configuring a MetroCluster system with SAS disk shelves and FibreBridge 6500N bridges.