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

404 Fabric OS Administrator’s Guide
53-1001336-02
Traffic Isolation Routing
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Additional considerations when disabling failover
If failover is disabled, be aware of the following considerations:
• This feature is intended for use in simple linear fabric configurations, such as that shown in
Figure 50 on page 402.
• Ensure that there are non-dedicated paths through the fabric for all devices that are not in a TI
zone.
• If you create a TI zone with just E_Ports, failover must be enabled. If failover is disabled, the
specified ISLs will not be able to route any traffic.
• If the path between devices in a TI zone is broken, no inter-switch RSCNs are generated. Each
switch that is part of the TI zone generates RSCNs to locally attached devices that are part of
the TI zone and are registered to receive RSCNs.
• Ensure that there are multiple paths between switches.
Disabling failover locks the specified route so that only TI zone traffic can use it. Non-TI zone
traffic, including domain controller frames, are excluded from using the dedicated path. For
example, in Figure 51, if failover is disabled, Domain 2 cannot send domain controller frames
to Domain 3 and 4. Domain controller frames include zone updates and Name Server queries.
To avoid this problem, add a second, non-dedicated ISL between Domain 1 and 3.
FIGURE 51 Fabric incorrectly configured for TI zone with failover disabled
• It is recommended that TI zone definitions and regular zone definitions match.
In Figure 51, if failover is disabled, the initiator and target on Domain 1 lose connectivity, even
if they are in the same regular zone. To maintain local connectivity between these devices,
either enable failover or add N_Port “1,9” to the TI zone.
• It is recommended that the insistent Domain ID feature be enabled; if a switch changes its
active domain ID, the route is broken. See the configure command in the Fabric OS Command
Reference for information about setting insistent Domain ID.
FSPF routing rules and traffic isolation
All traffic must use the lowest cost path. FSPF routing rules take precedence over the TI zones, as
described in the following situations.
7
12
3
15
Domain 1 Domain 3
Domain 4
Domain 2
8
19
6
9
5
= Dedicated Path
= Ports in the TI zone