2011/08/07

ccna 640-802 s1-1~2/9@7/791

QUESTION NO: 1
Both switches and hubs are being utilized within the TestKing network. Which of
the following is true regarding the use of switches and hubs for network
connectivity in this network?
A. Switches take less time to process frames than hubs take
B. Hubs can filter frames
C. Switches do not forward broadcasts
D. Switches increase the number of collision domains in the network
E. Using hubs can increase the amount of bandwidth available to hosts
F. None of the above

Answer: D
Explanation:
The biggest benefit of using switches instead of hubs in your internetwork is that each
switch port is actually its own collision domain. (Conversely, a hub creates one large
collision domain.) But even armed with a switch, you still can't break up broadcast
domains. Neither switches nor bridges will do that. They'll typically simply forward all
broadcasts instead. Switch creates the collision domain per port, so we can say switch
increase the number of collision domains.

*

QUESTION NO: 2
Which one of the following characteristics is true regarding the use of hubs and
switches?
A. Hubs can have their ports be configured with VLANs
B. Using hubs is costly with regard to bandwidth availability.
C. Switches can not forward broadcasts.
D. Switches are more efficient than hubs in processing frames.
E. Switches increase the number of collision domains in the network.

Answer: E
Explanation: Switches increases the number of collisions domains in the network.
Switches that are configured with VLANs will reduce the size of the collision
domains by increasing the number of collision domains in a network, but making
them smaller than that of one big, flat network.
Incorrect Answers:
A. Switches are capable of VLAN configurations, but hubs are not.
B. Hubs are generally the least costly method possible to connect multiple devices
together in a network.
C. Switches forward broadcasts and multicasts, by default, to all ports within the same
VLAN. Only routers block all broadcast traffic by default.
D. Switches and hubs can be equally efficient in processing frames, in theory. In practice,
switches are generally more efficient as they usually have more CPU and memory
allocated to them, and are generally much more expensive than a simple hub.

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