Zoning is an FC switch function that enables nodes within the fabric to be logically segmented into groups that can communicate with each other (see Figure). When a device (host or storage array) logs onto a fabric, it is registered with the name server. When a port logs onto the fabric, it goes through a device discovery process with other devices registered in the name server. The zoning function controls this process by allowing only the members in the same zone to establish these link-level services.

Multiple zone sets may be defined in a fabric, but only one zone set can be active at a time. A zone set is a set of zones and a zone is a set of members. A member may be in multiple zones. A port or a node can be a member of multiple zones. Zone sets comprise a group of zones that can be activated or deactivated as a single entity in a fabric. Only one zone set per fabric can be active at a time.