Dell Brocade G620 Brocade 8.0.1 Fabric OS Administratiors Guide - Page 359

Additional considerations when disabling failover, FSPF routing rules and traffic isolation

Page 359 highlights

Traffic Isolation Zoning TABLE 74 Traffic behavior when failover is enabled or disabled in TI zones Failover enabled Failover disabled If the dedicated path is not the shortest path or if the dedicated path is broken, the TI zone traffic will use a non-dedicated path instead. If the dedicated path is not the shortest path or if the dedicated path is broken, traffic for that TI zone is halted until the dedicated path is fixed. This condition is RAS logged. 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 the dedicated path is the shortest path or if there are no other paths through the fabric. This condition is RAS logged. For example, in Figure 37 on page 358, if the dedicated ISL between Domain 1 and Domain 3 goes offline, then the following occurs, depending on the failover option: ∙ If failover is disabled for the TI zone, the TI zone traffic is halted until the ISL between Domain 1 and Domain 3 is back online. ∙ If failover is enabled for the TI zone, the TI zone traffic is routed from Domain 1 to Domain 3 through E_Ports "1,2" and "3,10". Also, when TI zone traffic enters the non-TI path, the TI zone traffic continues to flow through that path. In this example, when the TI zone traffic is routed through E_Ports "1,2" and "3,10", that traffic continues through the non-TI path between domains 3 and 4, even though the TI path between domains 3 and 4 is not broken. 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 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. ∙ If failover is enabled for the TI zone, non-TI zone traffic is routed from Domain 1 to Domain 3 through the dedicated ISL. Also, when non-TI zone traffic enters the TI path, the non-TI zone traffic continues to flow through that path. In this example, when the non-TI zone traffic is routed through E_Ports "1,1" and "3,9", that traffic continues through E_Ports "3,12" and "4,7", even though the non-dedicated ISL between domains 3 and 4 is not broken. Additional considerations when disabling failover If failover is disabled, be aware of the following considerations: ∙ Disabling failover locks the specified route so that only TI zone traffic can use it. Non-TI zone traffic is excluded from using the dedicated path. Ensure that there are also non-dedicated paths through the fabric for all devices that are not in a TI zone. ∙ If you create a TI zone with E_Ports only, and no N_Ports, failover must be enabled. If failover is disabled, the specified ISLs will not be able to route any traffic. ∙ It is recommended that TI zone definitions and regular zone definitions match. For example, if four N_Ports are TI zoned together, then these same N_Ports should also be regularly zoned together. ∙ It is strongly recommended that the insistent Domain ID feature be enabled. TI zone members are defined by Domain ID and Port Index. If a switch changes its active domain ID, the route defined by the TI zone becomes unknown, breaking the dedicated path. 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. If the dedicated ISL is not the lowest cost path ISL, then the following rules apply: ∙ If failover is enabled, the traffic path for the TI zone is broken, and TI zone traffic uses the lowest cost path instead. ∙ If failover is disabled, the TI zone traffic is blocked. If the dedicated ISL is the only lowest cost path ISL, then the following rules apply: ∙ If failover is enabled, non-TI zone traffic as well as TI zone traffic uses the dedicated ISL. Brocade Fabric OS Administration Guide, 8.0.1 53-1004111-02 359

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TABLE 74
Traffic behavior when failover is enabled or disabled in TI zones
Failover enabled
Failover disabled
If the dedicated path is not the shortest path or if the dedicated path is
broken, the TI zone traffic will use a non-dedicated path instead.
If the dedicated path is not the shortest path or if the dedicated path is
broken, traffic for that TI zone is halted until the dedicated path is fixed.
This condition is RAS logged.
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 the dedicated
path is the shortest path or if there are no other paths through the fabric.
This condition is RAS logged.
For example, in
Figure 37
on page 358, if the dedicated ISL between Domain 1 and Domain 3 goes offline, then the following occurs,
depending on the failover option:
If failover is disabled for the TI zone, the TI zone traffic is halted until the ISL between Domain 1 and Domain 3 is back online.
If failover is enabled for the TI zone, the TI zone traffic is routed from Domain 1 to Domain 3 through E_Ports "1,2" and "3,10".
Also, when TI zone traffic enters the non-TI path, the TI zone traffic continues to flow through that path. In this example, when
the TI zone traffic is routed through E_Ports "1,2" and "3,10", that traffic continues through the non-TI path between domains 3
and 4, even though the TI path between domains 3 and 4 is not broken.
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 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.
If failover is enabled for the TI zone, non-TI zone traffic is routed from Domain 1 to Domain 3 through the dedicated ISL. Also,
when non-TI zone traffic enters the TI path, the non-TI zone traffic continues to flow through that path. In this example, when
the non-TI zone traffic is routed through E_Ports "1,1" and "3,9", that traffic continues through E_Ports "3,12" and "4,7", even
though the non-dedicated ISL between domains 3 and 4 is not broken.
Additional considerations when disabling failover
If failover is disabled, be aware of the following considerations:
Disabling failover locks the specified route so that only TI zone traffic can use it. Non-TI zone traffic is excluded from using the
dedicated path. Ensure that there are also non-dedicated paths through the fabric for all devices that are not in a TI zone.
If you create a TI zone with E_Ports only, and no N_Ports, failover must be enabled. If failover is disabled, the specified ISLs will
not be able to route any traffic.
It is recommended that TI zone definitions and regular zone definitions match. For example, if four N_Ports are TI zoned
together, then these same N_Ports should also be regularly zoned together.
It is strongly recommended that the insistent Domain ID feature be enabled. TI zone members are defined by Domain ID and
Port Index. If a switch changes its active domain ID, the route defined by the TI zone becomes unknown, breaking the dedicated
path. 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.
If the dedicated ISL is not the lowest cost path ISL, then the following rules apply:
If failover is enabled, the traffic path for the TI zone is broken, and TI zone traffic uses the lowest cost path instead.
If failover is disabled, the TI zone traffic is blocked.
If the dedicated ISL is the only lowest cost path ISL, then the following rules apply:
If failover is enabled, non-TI zone traffic as well as TI zone traffic uses the dedicated ISL.
Traffic Isolation Zoning
Brocade Fabric OS Administration Guide, 8.0.1
53-1004111-02
359