HP StorageWorks 1606 Brocade Fabric OS Administrator's Guide v6.3.0 (53-100133 - Page 437

Traffic Isolation Routing 18 In Figure 49, all traffic entering Domain 1 from N_Ports 7 and 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 devices through N_Ports 5 and 6. Traffic coming from other ports in Domain 1 would not use E_Port 1, but would use E_Port 2 instead. 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. Disable failover if you want to guarantee that TI zone traffic uses only the dedicated path, and that no other traffic can use the dedicated path. Enable failover if you want traffic to have alternate routes if either the dedicated or non-dedicated paths cannot be used. ATTENTION If failover is disabled, use care when planning your TI zones so that non-TI zone devices are not isolated. If this feature is not used correctly, it can cause major fabric disruptions that are difficult to resolve. See "Additional considerations when disabling failover" on page 396 for additional information about using this feature. Table 80 compares the behavior of traffic when failover is enabled and disabled. TABLE 80 Comparison of traffic behavior when failover is enabled or disabled in TI zones Failover enabled Failover disabled If the dedicated path cannot be used, the TI zone traffic If the dedicated path cannot be used, traffic for that TI will use a non-dedicated path instead. zone is halted until the dedicated path is fixed. Non-TI zone traffic will use the dedicated path if no other paths through the fabric exist, or if the non-dedicated paths are not the shortest paths. Non-TI zone traffic will never use the dedicated path, even if there are no other paths through the fabric. Local connectivity is maintained as long as the local devices are in the same regular zone. Local connectivity is lost if the local devices are not in the same TI zone, even if they are in the same regular zone. For example, in Figure 49 on page 394, 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. If the non-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, non-TI zone traffic is routed from Domain 1 to Domain 3 through the dedicated ISL. • If failover is disabled for the TI zone, non-TI zone traffic is halted until the non-dedicated ISL between Domain 1 and Domain 3 is back online. Fabric OS Administrator's Guide 395 53-1001336-01