HP A7533A - Brocade 4Gb SAN Switch Base, Administrator'S Manual

Page: 342 / 576

340 Optimizing fabric behavior
Figure 42 Traffic Isolation zone creating a dedicated path through the fabric
In Figure 42 , 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. See 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 when either the dedicated or non-dedicated
paths cannot be used.
IMPORTANT: 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 341 for additional information
about using this feature.
Table 75 compares the behavior of traffic when failover is enabled and disabled.
For example, in Figure 42 , if the dedicated ISL between Domain 1 and Domain 3 goes offline, 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, the following occurs, depending
on the failover option:
= Dedicated Path
Domain 1 Domain 3
Domain 4
1 9
9
2
10
4
= Ports in the TI zone
6
7
12
7
8
5
Table 75 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.