CCNA Exercise Lab 2

Answer the following questions based on the following graphic.

CCNA Exercise Lab 2 Image 1

1. Which is the root bridge?

Ans – Bridge ID-1900A is the root bridge. A root bridge is a Switch which is located at the top of the network and connecting to other switches.

2. What are the designated ports?

Ans – A designated port is the port on a segment which has the lease cost to reach to the switch. In this design port0 on switch 1900A is the designated port and port 1 on either switch 1900B, 1900C could be a designated port. A switch can have multiple designated ports but has only one ‘root port’.

3. What are the non-designated ports?

Ans – A designated port is called a non-designated port if it has no root port. Non-designated ports have no role to play and are put in blocking state.

4. Which ports are blocking?

Ans – The port-1 on Switch 1900B and 1900C, one of the port is in blocking state or non-designated,

Review Questions

  1. Which LAN switch method runs a CRC on every frame?
    • Cut-through
    • Store and forward
    • FragmentCheck
    • FragmentFree
    • Ans- B
  2. Which LAN switch type only checks the hardware address before forwarding a frame?
    • Cut-through
    • Store and forward
    • FragmentCheck
    • FragmentFree
    • Ans- A
  3. What is true regarding the STP blocked state of a port? (Choose all that )
    • No frames are transmitted or received on the blocked
    • BPDUs are sent and received on the blocked
    • BPDUs are still received on the blocked
    • Frames are sent or received on the blocked
    • Ans- C,D
  4. Layer-2 switching provides which of the following?
    • Hardware-based bridging (MAC)
    • Wire-speed
    • High latency
    • High-cost
    • Ans- A, B
  5. What is used to determine the root bridge in a network? (Choose all that )
    • Priority
    • Cost of the links attached to the switch
    • MAC address
    • IP address Ans – Priority & MAC
    • Ans- A, C
  6. What is used to determine the designated port on a bridge?
    • Priority
    • Cost of the links attached to the switch
    • MAC address
    • IP address
    • Ans- B
  7. What are the four port states of an STP switch?
    • Learning
    • Learned
    • Listened
    • Heard
    • Listening
    • Forwarding
    • Forwarded
    • Blocking
    • Gathering
    • Ans- A, E, F, H ( Blocking, Listening, Learning, Forwarding )
  8. What are the three distinct functions of layer-2 switching?
    • Address learning
    • Routing
    • Forwarding and filtering
    • Creating network loops
    • Loop avoidance
    • IP addressing
    • Ans- A, C, E
  9. What is true regarding BPDUs?
    • They are used to send configuration messages using IP
    • They are used to send configuration messages using multicast frames.
    • They are used to set the cost of STP
    • They are used to set the bridge ID of a
    • Ans - B
  10. If a switch determines that a blocked port should now be the designated port, what state will the port go into?
    • Unblocked
    • Forwarding
    • Listening
    • Listened
    • Learning
    • Learned
    • Ans- C
  11. What is the difference between a bridge and a layer-2 switch? (Choose all that )
    • Bridges can only have one spanning-tree instance per
    • Switches can have many different spanning-tree instances per switch.
    • Bridges can have many spanning-tree instances per
    • Switches can only have one spanning-tree instance per
    • Ans- A, B
  12. What is the difference between a bridge and a layer-2 switch? (Choose all that )
    • Switches are software
    • Bridges are hardware
    • Switches are hardware
    • Bridges are software
    • Ans- C, D
  13. What does a switch do when a frame is received on an interface and the destination hardware address is unknown or not in the filter table?
    • Forwards the switch to the first available link
    • Drops the frame
    • Floods the network with the frame looking for the device
    • Sends back a message to the originating station asking for a name resolution
    • Ans- C
  14. Which LAN switch type waits for the collision window to pass before looking up the destination hardware address in the MAC filter table and forwarding the frame?
    • Cut-through
    • Store and forward
    • Fragment Check
    • Fragment Free
    • Ans- D
  15. What is the default LAN switch type on a 1900 switch?
    1. Cut-through
    2. Store and forward
    3. FragmentCheck
    4. FragmentFree
    5. Ans- D
  16. How is the bridge ID of a switch communicated to neighboring switches?
    • IP Routing
    • STP
    • During the four STP states of a switch
    • Bridge Protocol Data Units
    • Broadcasts during convergence times
    • Ans- D ( BPDUs )
  17. How is the root port on a switch determined?
    • The switch determines the highest cost of a link to the root
    • The switch determines the lowest cost of a link to the root
    • The fastest BPDU transfer rate is determined by sending and receiving BPDUs between switches, and that interface becomes the root
    • The root bridge will broadcast the bridge ID, and the receiving bridge will determine what interface this broadcast was received on and make this interface the root
    • Ans - B
  18. How many root bridges are allowed in a network?
    • 10
    • 1
    • One for each switch
    • 20
    • Ans- B. Only 1 per network
  19. What could happen on a network if no loop avoidance schemes are put in place?
    • Faster convergence times
    • Broadcast storms
    • Multiple frame copies
    • IP routing will cause flapping on a serial link
    • Ans- B
  20. What is the default priority of STP on a switch?
    • 32,768
    • 3276
    • 100
    • 10
    • 1
    • Ans- A

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