Failover In Ti Zones; Bandwidth Calculation During Failover - Brocade Communications Systems StoreFabric SN6500B Administrator's Manual

2
FCIP Trunking
5. Display local and crossport interface details for xge0.
NOTE
If the source and destination addresses are on different subnets, you must configure IP routes to
the destination addresses. Refer to
NOTE
For more information on using Fabric OS commands, optional arguments, and command output
refer to the Fabric OS Command Reference Manual.

Failover in TI zones

In Traffic Isolation (TI) zone configurations with failover enabled, non-TI zone traffic will use the
dedicated path if no other E_Port or VE_Port paths exist through the fabric or if the non-dedicated
paths are not the shortest paths. Note that a higher-bandwith tunnel with multiple circuits will
become the shortest path compared to a tunnel with one circuit. A TI zone cannot subvert Fabric
Shortest Path First Presented (FSPF) protocol. Data will never take a higher cost path just because
a TI zone has been configured to do so. It may be necessary to configure explicit link cost to
produce Equal-Cost Multi-Path (ECMP) or to prevent FCIP trunk costs from changing in the event
that a circuit goes offline.

Bandwidth calculation during failover

The bandwidth of higher-metric circuits is not calculated as available bandwidth on an FCIP tunnel
until all lowest metric circuits have failed. Following is an example.
Assume the following configurations for circuits 0 through 3:
•
•
The following actions occur during circuit failures:
•
•
•
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portshow ipif 8/xge0
Circuits 0 and 1 are created with a metric of 0. Circuit 0 is created with a maximum
transmission rate of 1 Gbps, and circuit 1 is created with a maximum transmission rate of 500
Mbps. Together, circuits 0 and 1 provide an available bandwidth of 1.5 Gbps.
Circuits 2 and 3 are created with a metric of 1. Both are created with a maximum transmission
rate of 1 Gbps, for a total of 2 Gbps. This bandwidth is held in reserve.
If either circuit 0 or circuit 1 fails, traffic flows over the remaining circuit while the failed circuit
is being recovered. The available bandwidth is still considered to be 1.5 Gbps.
If both circuit 0 and circuit 1 fail, there is a failover to circuits 2 and 3, and the available
bandwidth is updated as 2 Gbps.
If a low metric circuit becomes available again, the high metric circuits go back to standby
status, and the available bandwidth is updated again as each circuit comes online. For
example, if circuit 0 is recovered, the available bandwidth is updated as 1 Gbps. If circuit 1 is
also recovered, the available bandwidth is updated as 1.5 Gbps.
"Configuring an IP route" on page 41.
Fabric OS FCIP Administrator's Guide
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