WEBVTT

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Three Cisco switches form a triangle with two paths between the hosts.

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Give switch one a lower bridge priority so it becomes the root for VLAN one.

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On switch three, the root port forwards and the alternate port blocks.

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Ping from one host to the other to check the starting path.

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Shut down the root port on switch three to simulate a link failure.

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The alternate port becomes the new root port and starts forwarding.

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Ping again to confirm the hosts can communicate over the backup path.

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Bring the original link up and check that the original port roles return.

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Enable root guard on switch one’s port toward switch two.

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A better priority from switch two puts the guarded port in a root-inconsistent state.

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Restore switch two’s priority and check that the guarded port forwards again.

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Finish with a successful ping to confirm the restored path.