Tuesday, February 11, 2014

CCNA 3 Chapter 5 -2014

1. Which two criteria does a switch use to select the root bridge? (Choose two.)
bridge priority
base MAC address

2. Which two statements are true about the default operation of STP in a Layer 2 switched environment that has redundant connections between switches? (Choose two.)
Decisions on which port to block when two ports have equal cost depend on the port priority and identity.
Non-root switches each have only one root port.

3. Refer to the exhibit. All switches in the network have empty MAC tables. STP has been disabled on the switches in the network. How will a broadcast frame that is sent by host PC1 be handled on the network?
Switch SW1 will forward the broadcast out all switch ports, except the originating port. This will generate an endless loop in the network.

4. Which two statements describe the BIDs used in a spanning tree topology? (Choose two.)
They consist of a bridge priority and MAC address.
They are used by the switches in a spanning tree topology to elect the root bridge.


5. Which statement or set of paired statements correctly compares STP with RSTP?
STP waits for the network to converge before placing ports into forwarding state. RSTP places designated ports into forwarding state immediately.

6. How can a network administrator influence which STP switch becomes the root bridge?
Set the switch priority to a smaller value than that of the other switches in the network.

7. In which STP state does a port record MAC addresses but not forward user data?
learning

8. When PVST+ was developed, the Bridge ID was modified to include which information?
VLAN ID

9. What is the first step in the process of convergence in a spanning tree topology?
election of the root bridge

10. What two elements will exist in a converged network with one spanning tree? (Choose two.)
one root bridge per network
one root port per non-root bridge

11. Refer to the exhibit. What can be determined from the output shown?
The priority was statically configured to identify the root.

12. What two features of the Spanning-Tree Protocol contribute to the time it takes for a switched network to converge after a topology change occurs? (Choose two.)
the max-age timer
the forward delay

13. What three link types have been defined for Rapid Spanning-Tree Protocol? (Choose three.)
shared
edge-type
point-to-point

14. Refer to the exhibit. The spanning-tree port priority of each interface is at the default setting. The network administrator enters the spanning-tree vlan 1 root primary command on S4. What is the effect of the command?
Gi0/2 on S3 transitions to a root port.

15. In which two ways is the information that is contained in BPDUs used by switches? (Choose two.)
to identify the shortest path to the root bridge
to determine which ports will forward frames as part of the spanning tree

16. What Rapid Spanning Tree Protocol (RSTP) role is assigned to the forwarding port elected for every Ethernet LAN segment that links two switches?
designated

17. Which two items are true regarding the spanning-tree portfast command? (Choose two.)
PortFast is Cisco proprietary.
If an access port is configured with PortFast, it immediately transitions from a blocking to a forwarding state.

18. Which two actions does an RSTP edge port take if it receives a BPDU? (Choose two.)
immediately loses its edge status
becomes a normal spanning-tree port

19. Refer to the exhibit. Server sends an ARP request for the MAC address of its default gateway. If STP is not enabled, what will be the result of this ARP request?
Switch_A and Switch_B will continuously flood the message onto the network.

20. Which three statements are accurate regarding RSTP and STP? (Choose three.)
Both RSTP and STP use the portfast command to allow ports to immediately transition to forwarding state.
Configuration commands to establish primary and secondary root bridges are identical for STP and RSTP.

Because of the format of the BPDU packet, RSTP is backward compatible with STP.




CCNA 3 Chapter 5 Answers

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