HP StorageWorks 4000/6000/8000 .HP StorageWorks SAN Design Reference Guide, Pa - Page 163

Rule nl number Description 2 The supported limit of interconnected switches in a single fabric is 31, provided that any Edge Switch 2/32 or Director 2/64 in the fabric is deployed at the edge of the fabric. 3 In fabric configurations exceeding 1,500 devices, use Edge Switch 2/32 and Director 2/64 at the edge of the fabric. 4 A maximum of three switch hops (four switches) is supported between any two devices. 5 A ring fabric topology is supported with a maximum of seven M-series switches. 6 Assign a unique domain number (domain ID) and a unique WWN to each switch. The switch configuration parameters must be the same for each switch. Do not configure any switches with a domain ID of 8, which is reserved for HP-UX. 7 HP requires that all switches in a single-fabric SAN or multi-fabric SAN use the same firmware version for the same switch models. You can use two successive switch firmware versions nl temporarily in one fabric or multiple fabrics when updating switch firmware. NOTE: Not all topologies can support the maximum port or switch count. ISL maximums When designing a fabric using 12-port, 16-port, 24-port, and 32-port switches, all ports can be used as ISLs, with a maximum of one half of the total ISL port count configured to the same destination switch. NOTE: The Edge Switch 2/12 requires licensing to enable ISL ports. SAN Design Reference Guide 163