Answers to Review Questions
105
Answers to Review Questions
1.
B. Store-and-forward LAN switching checks every frame for CRC
errors. It has the highest latency of any LAN switch type.
2.
A. The cut-through method does no error checking and has the low-
est latency of the three LAN switch types. Cut-through only checks the
hardware destination address before forwarding the frame.
3.
A, E. Bridges break up collision domains, which would increase
the number of collision domains in a network and also make smaller
collision domains.
4.
A, B. Layer-2 switching uses ASICs to provide frame filtering and is
considered hardware based. Layer-2 switching also provides wire-
speed frame transfers, with low latency.
5.
B. Layer-2 switches break up collision domains and will decrease
congestion on your network.
6.
B. The modified version of cut-through is called FragmentFree.
7.
A, C. Store-and-forward latency (delay) will always vary because the
complete frame must be received before the frame is transmitted back
out the switch.
8.
A, C, E. Layer-2 features that increase available bandwidth include
address learning, forwarding and filtering of the network, and loop
avoidance.
9.
C. By adding a switch, you can effectively segment the network and
provide 100Mbps to the server and 10MBps to the hosts.
10.
B. Spanning Tree Protocol (STP) will make sure that no network
loops occur at layer 2.
11.
B. Switches break up collision domains, and routers break up broad-
cast domains.
12.
C, E. There are three methods of LAN switching: cut-through,
FragmentFree, and store-and-forward. Cut-through and store-and-
forward are the two main methods, according to Cisco.
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