QUESTION 44
What value is primarily used to determine which port becomes the root port on each non-root switch in a
spanning-tree topology?
A. lowest port MAC address
B. port priority number and MAC address.
C. VTP revision number
D. highest port priority number.
E. path cost
Correct Answer: E
Explanation
The path cost to the root bridge is the most important value to determine which port will become the root port
on each non-root switch. In particular, the port with lowest cost to the root bridge will become root port (on nonroot
switch).
QUESTION 45
Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network? (Choose two)
A. 802.1d
B. VTP
C. 802.1q
D. STP
E. SAP
Correct Answer: AD
QUESTION 46
In which circumstance are multiple copies of the same unicast frame likely to be transmitted in a switched LAN?
A. after broken links are re-established
B. in an improperly implemented redundant topology
C. when upper-layer protocols require high reliability
D. during high traffic periods
E. when a dual ring topology is in use
Correct Answer:B
Explanation
If we connect two switches via 2 or more links and do not enable STP on these switches then a loop (which
creates multiple copies of the same unicast frame) will occur. It is an example of an improperly implemented
redundant topology.
QUESTION 47
Which port state is introduced by Rapid-PVST?
A. learning
B. listening
C. discarding
D. forwarding
Correct Answer: C
QUESTION 48
Based on the information given, which switch will be elected root bridge and why?
A. Switch A, because it has the lowest MAC address
B. Switch A, because it is the most centrally located switch
C. Switch B, because it has the highest MAC address
D. Switch C, because it is the most centrally located switch
E. Switch C, because it has the lowest priority
F. Switch D, because it has the highest priority
Correct Answer: E
QUESTION 49
Which term describes a spanning-tree network that has all switch ports in either the blocking or forwarding
state?
A. redundant
B. spanned
C. provisioned
D. converged
Correct Answer: D
Explanation
Spanning Tree Protocol convergence (Layer 2 convergence) happens when bridges and switches have
transitioned to either the forwarding or blocking state. When layer 2 is converged, root bridge is elected and all
port roles (Root, Designated and Non-Designated) in all switches are selected.
QUESTION 50
Three switches are connected to one another via trunk ports. Assuming the default switch configuration, which
switch is elected as the root bridge for the spanning-tree instance of VLAN 1?
A. the switch with the highest MAC address
B. the switch with the lowest MAC address
C. the switch with the highest IP address
D. the switch with the lowest IP address
Correct Answer: B
QUESTION 51
Based on the network shown in the graphic
Which option contains both the potential networking problem and the protocol or setting that should be used to
prevent the problem?
A. routing loops, hold down timers
B. Switching loops, split horizon
C. routing loops, split horizon
D. Switching loops, VT
E. routing loops, STP
F. Switching loops, STP
Correct Answer: F