1. A network device for use in a Fibre Channel network, the network device comprising: one or more Fibre Channel ports; and a zoning engine for implementing zoning in the Fibre Channel network, the zoning engine comprising: (a) a content addressable memory configured or designed to store information identifying distinct destinations on said Fibre Channel network; (b) a membership table designed or configured to store zoning decision vectors for the distinct destinations identified in the content addressable memory, wherein each zoning decision vector comprises a separate zoning rule for multiple sources on the Fibre Channel network; and (c) logic for (i) selecting a zoning decision vector from the membership table using destination information from an incoming frame, and (ii) selecting a zoning rule from the selected zoning decision vector using source information from said incoming frame.