Brocade Network Advisor SAN User Manual v12.0.0 (53-1002696-01, April 2013)

764 Brocade Network Advisor SAN User Manual
53-1002696-01
FCIP trunking
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• In a scenario where a FCIP tunnel has multiple circuits of different metrics the data will flow
over the lower metric circuits unless a failover condition occurs, as described in “FCIP circuit
failover capabilities”.
• The maximum bandwidth for a single circuit is 1 Gbps. However, a maximum of 10 Gbps per
circuit is allowed between 10 GbE ports on 8 Gbps Extension Blades when both blades are
running Fabric OS 7.0 or greater.
FCIP circuit failover capabilities
Each FCIP circuit is assigned a metric, which is used in managing failover for FC traffic. Typically,
the metric will be either 0 or 1. If a circuit fails, FCIP Trunking tries first to retransmit any pending
send traffic over another lowest metric circuit. In Figure 342, circuit 1 and circuit 2 are both lowest
metric circuits. Circuit 1 has failed, and transmission fails over to circuit 2, which has the same
metric. Traffic that was pending at the time of failure is retransmitted over circuit 2. In order
delivery is ensured by the receiving 8 Gbps Extension Switch.
FIGURE 342 Link loss and retransmission over peer lowest metric circuit
In Figure 343, circuit 1 is assigned a metric of 0, and circuit 2 is assigned a metric of 1. In this
case, circuit 2 is a standby that is not used unless there are no lowest metric circuits available. If all
lowest metric circuits fail, then the pending send traffic is retransmitted over any available circuits
with the higher metric,
FIGURE 343 Failover to a higher metric standby circuit
8 Gbps
Extension
switch
Circuit 1
Circuit 2
213
X
13 ?
Resend 2
8 Gbps
Extension
switch
Circuit 1 - Metric 0 - Active
Circuit 2 - Metric 1 - Standby
8 Gbps
Extension
switch
8 Gbps
Extension
switch