Brocade Communications Systems Network Advisor 12.3.0, User Manual

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940 Brocade Network Advisor SAN User Manual
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FCIP trunking
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A valid failover group requires at least one metric 0 circuit and at least one metric 1 circuit. If
you do not configure these, a warning will display. If there is no metric 0 circuit and only a
metric 1 circuit, the metric 1 circuit will be used, regardless of whether there are metric 0
circuits in another failover group.
•
The number of valid failover groups defined per tunnel is limited by the number of circuits that
you can create for the switch model. For an 8 Gbps Extension Blade, you can configure up to 5
valid groups on an 10-circuit tunnel. On an 8 Gbps Extension Switch, you could have up to 3
valid groups because you can only configure 6 circuits per tunnel.
•
Consider available WAN bandwidth requirements when configuring failover circuit groups.
Refer to
“Bandwidth calculation during failover” on page 938.
Examples of circuit failover in groups
Tables Table 72 through Table 74 provide examples of how failover occurs on circuits with different
bandwidths configured in failover groups.
Table 72 illustrates circuit failover in a tunnel with two failover groups, each with two circuits. All
data through the tunnel is initially load balanced over Circuits 1 and 2. The following occurs during
circuit failover:
•
If circuit 1 fails, circuit 3 becomes active and data is load balanced over circuit 2 and 3.
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If circuit 2 fails, circuit 4 becomes active and data is load balanced over circuit 1 and 4.
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If both circuit 1 and 2 fail, circuit 3 and.4 become active and data is load balanced over both
circuits.
Table 73 illustrates circuit failover in a tunnel with one failover group containing three circuits, In
this case, failover occurs as if circuits are not part of a failover group. Circuit 2 and 3, both with
metric 1, become active only after circuit 1 with metric 0 fails.
TABLE 72 Tunnel with two failover groups with two circuits
Circuits in tunnel Failover group ID Circuit bandwidth In use for tunnel data
Circuit 1
Metric 0 1 500Mb If active, yes.
Circuit 2
Metric 0 2 1000Mb If active, yes.
Circuit 3
Metric 1 1 500Mb Only when circuit 1
fails.
Circuit 4
Metric 1 2 1000Mb Only when circuit 2
fails.
TABLE 73 Tunnel with one failover groups with three circuits
Circuits in tunnel Failover group ID Circuit bandwidth In use for tunnel data
Circuit 1
Metric 0 1 1000Mb If active, yes.
Circuit 2
Metric 1 1 500Mb Only when circuit 1
fails.
Circuit 3
Metric 1 1 500Mb Only when circuit 1
fails.