Brocade Fabric OS Administrator's Guide Supporting Fabric OS v6.3.0 (53-1001336-02, November 2009)

Fabric OS Administrator’s Guide 403
53-1001336-02
Traffic Isolation Routing
18
In Figure 50, 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 404 for additional
information about using this feature.
Table 82 compares the behavior of traffic when failover is enabled and disabled.
For example, in Figure 50 on page 402, 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.
TABLE 82 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
will use a non-dedicated path instead.
If the dedicated path cannot be used, traffic for that TI
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.