HP A7533A HP StorageWorks Fabric OS 6.1.1 administrator guide (5697-0235, Dece - Page 294

the TI zone. If failover is disabled, the TI zone traffic stops until the dedicated path is configured to be the shortest path. Domain 1 8 1 9 3 Domain 3 9 14 12 15 16 = Dedicated Path = Ports in the TI zone Domain 2 Figure 29 Dedicated path is not the shortest path 7 6 5 Domain 4 NOTE: For information about setting or displaying the FSPF cost of a path, see the linkCost and topologyShow commands in the Fabric OS Command Reference. Traffic Isolation over FC routers This section describes how TI zones work with Fibre Channel routing (TI over FCR). See "Using the FC-FC routing service" on page 311 for information about FC routers, phantom switches, and the FC-FC Routing Service. Some VE_Port-based features, such as tape pipelining, require the request and corresponding response traffic to traverse the same VE_Port tunnel across the metaSAN. To ensure that the request and response traverse the same VE_Port tunnel, you must set up Traffic Isolation zones in the edge and backbone fabrics: • Set up a TI zone in an edge fabric to guarantee that traffic from a specific device in that edge fabric is routed through a particular EX_Port or VEX_Port. • Set up a TI zone in the backbone fabric to guarantee that traffic between two devices in different fabrics is routed through a particular ISL (VE_Ports or E_Ports) in the backbone. This combination of TI zones in the backbone and edge fabrics ensures that the traffic between devices in different fabrics traverses the same VE_Port tunnel in a backbone fabric. Figure 30 shows how three TI zones form a dedicated path between devices in different edge fabrics. The backbone fabric can contain one or more FC routers. 294 Optimizing fabric behavior