In a Fiber Channel SAN and its included routers, each router contains only the LSAN zones that contain devices attached to edge fabrics which are connected to the router. LSAN zone entries include the fabric ID (FID) of each device in addition to the WWN. When a router obtains a new zone database for a newly connected or changed fabric, the router scans the LSAN zone entries for fabric IDs matching a fabric connected to the router and stores those entries. All other LSAN zone entries are not stored. In this manner the size of the relevant tables are reduced, which allows for greater expansion of the SAN as a whole.