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18 Cards in this Set
- Front
- Back
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What do bridges and switches running STP use to exchange information?
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Bridge Protocol Data Units (BPDU's)
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What do BPDU's use to send configuration information?
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multicast frames with the bridge ID of each device
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What is a bridge ID used for?
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determining the root bridge and root port
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How long is a bridge ID?
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8 bytes, including the device's priority and MAC address
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What is the default device priority?
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32768
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How is the root bridge chosen?
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by highest priority; lower MAC address wins ties
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What are the four spanning-tree port states?
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blocking, listening, learning, and forwarding
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How does a port behave when in blocking mode?
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it won't forward frames, but listens to BPDU's
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What spanning-tree port mode is the default on startup?
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blocking
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How does a port behave when in listening mode?
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it listens to BPDU's to ensure no loops will be created before forwarding
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How does a port behave when in learning mode?
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it learns MAC addresses and builds a filter table, but does not forward frames
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When are listening and learning states primarily used?
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When a topology change occurs
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When do ports use listening mode?
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When a blocked port determines that it should now be the designated port; it listens to determine that no loops will be created
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At what point does convergence begin?
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when all bridges and switches have trasitioned to forwarding or blocking states
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Is data forwarded during convergence?
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no
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Why is convergence important?
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to ensure all devices have the same database
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How long does convergence take?
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about 50 seconds
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What is a forward delay?
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the time necessary to transition a port from listening to learning, or from learning to forwarding
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