HP StorageWorks 2/140 FW 08.01.00 McDATA Products in a SAN Environment Plannin - Page 113

Planning Considerations for Fibre Channel Topologies 3 - Fabric A zoned and Fabric B zoned - The fabrics join successfully only if the zone sets can be merged. If the fabrics cannot join, the connecting E_Ports segment and the fabrics remain independent. Zone sets for two directors or switches are compatible (the fabrics can join) only if the zone names for each fabric element are unique. The zone names for two fabric elements can be the same only if the zone member WWNs are identical for each duplicated zone name. General Fabric Design Considerations To be effective, the fabric topology design must: • Solve the customer's business problem and provide the required level of performance. • Meet the customer's requirements for high availability. • Be scalable to meet future requirements. Fabric Initialization When multiple directors or switches are connected, E_Port (ISL) communication must be established between fabric elements and the fabric must be initialized. During fabric initialization, the fabric elements: • Establish the operating mode for connected E_Port pairs and exchange link parameters (E_Port names, timeout values, classspecific information, and flow control parameters). • Exchange fabric parameters, select a principal switch, and assign Domain_IDs to all switches. • Employ a routing protocol to establish the shortest path through the fabric and program route tables for each fabric element. • Exchange the active zone set to ensure uniform zoning is enforced between all fabric elements. Fabric initialization is not a serial process. The process executes concurrently across all ISLs in the fabric, causing a massive flood of Class F traffic that must processed to the embedded port of each fabric element within a specified (fabric-wide) E_D_TOV. Planning Considerations for Fibre Channel Topologies 3-29