HP StorageWorks 8/80 HP StorageWorks Fabric OS 6.1.x administrator guide (5697 - Page 284

Figure 25 shows a fabric with a TI zone consisting of N_Ports "1,8" and "4,6" and E_Ports "1,1", "3,9", "3,12", and "4,7". The dotted line indicates the dedicated path from Domain 1 to Domain 4. Domain 1 7 1 8 9 2 Domain 3 9 10 12 = Dedicated Path = Ports in the TI zone 7 6 5 4 Domain 4 Figure 25 Traffic Isolation zone creating a dedicated path through the fabric In Figure 25, all traffic entering Domain 1 from N_Port 8 is routed through E_Port 1. Similarly, traffic entering Domain 3 from E_Port 9 is routed to E_Port 12, and traffic entering Domain 4 from E_Port 7 is routed to the device through N_Port 6. Traffic coming from other ports in Domain 1 would not use E_Port 1, but would use E_Port 2 instead. Other traffic is excluded from the dedicated path as long as other equal-cost routes through the fabric exist. For example, if the ISL formed by E_Ports "1,2" and "3,10" failed, all traffic between Domains 1 and 3 would use the ISL formed by E_Ports "1,1" and "3,9", even though that ISL is a dedicated path in a TI zone. Use the zone command to create and manage TI zones. Refer to the Fabric OS Command Reference for details about the zone command. TI zone failover A TI zone can have failover enabled or disabled. If the dedicated path cannot be used and failover is enabled, the TI zone traffic will use a non-dedicated path instead. If the dedicated path cannot be used and failover is disabled, the Traffic Isolation path is broken and traffic for that TI zone is halted until the dedicated path is fixed. For example, in Figure 25, if the dedicated ISL between Domain 1 and Domain 3 goes offline, then the following occurs, depending on the failover option: • If failover is enabled for the TI zone, the traffic is routed from Domain 1 to Domain 3 through E_Ports "1,2" and "3,10". • If failover is disabled for the TI zone, the traffic is halted until the ISL between Domain 1 and Domain 3 is back online. FSPF routing rules and Traffic Isolation FSPF routing rules take precedence over the TI zones, as described in the following situations: • If other paths through the fabric exist, but they are not the shortest path, then traffic uses the dedicated ISL. • If a TI zone creates a path that is not the lowest cost path and failover is enabled, the lowest cost path is used instead. If failover is not enabled, the traffic path for the TI zone is broken. 284 Optimizing fabric behavior