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18 Cards in this Set

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