HP StorageWorks 2/24 FW 07.00.00/HAFM SW 08.06.00 McDATA Products in a SAN Env - Page 106

Planning Considerations for Fibre Channel Topologies 3 • Heterogeneous fabric - Vendor interoperability in the fabric environment is supported; therefore, fabric elements can include directors, fabric switches, and open-fabric compliant products supplied by original equipment manufacturers (OEMs). To determine if interoperability is supported for a product or if communication restrictions apply, refer to the supporting publications for the product or contact McDATA. • Number of ISLs - The Intrepid 6064 Director supports 48 ISLs. The Intrepid 6140 Director supports 140 ISLs. The Intrepid 10000 Director supports seven ISLs per optical paddle pair. Sphereonclass switches support a maximum ISL count equal to half the number of Fibre Channel ports available on the product. For redundancy, at least two ISLs should connect any pair of director-class fabric elements. • Hop count - The Fibre Channel theoretical limit of ISL connections traversed (hop count) in a single path through the fabric is seven. The tested and verified hop count limit is three. NOTE: The hop count is equal to the number of ISL connections traversed in a single path, not the total number of ISL connections between devices. As shown in Figure 3-11, the number of ISL connections between switch S1 and S2 is four, while the number of hops is one. Factors to Consider When Implementing a Fabric Topology Director and switch-based fabrics offer scalable, high-performance, and high-availability connectivity solutions for the enterprise. To enable a multiswitch fabric, all fabric elements must be defined to the SAN management application (SANavigator 4.2 or EFCM 8.6) and must be physically cabled to form the requisite ISL connections. In addition, it is recommended that each director or switch in the fabric be assigned a unique preferred Domain_ID. When planning to implement a fabric topology, consider the following connectivity and cabling best practices: • Physical characteristics and performance objectives - Most enterprises have unique configurations determined by the characteristics of end devices, fabric elements, cost, and the installation's performance objectives (such as high data transfer rate or high availability). These factors, along with nondisruptive growth and service requirements, must be evaluated when planning an initial fabric. For additional information, refer to General Fabric Design Considerations on page 3-29. 3-20 McDATA Products in a SAN Environment - Planning Manual