Answers to Review Questions
71
Answers to Review Questions
1.
D. A broadcast sent on an Ethernet 802.3 LAN will go to all devices
in the Ethernet broadcast domain.
2.
C. Protocol Data Units are used to define data at each layer of the
OSI model. PDUs at the Network layer are called packets.
3.
A, C. When a virtual circuit is created, windowing is used for flow
control and acknowledgment of data.
4.
B. Data is encapsulated with a media access method at the Data Link
layer, and the Protocol Data Unit (PDU) is called a frame.
5.
D. The Transport layer receives large data streams from the upper
layers and breaks these up into smaller pieces called segments.
6.
C. If you place a frame inside another frame, this is called tunneling.
7.
C. MAC addresses, also called hardware addresses, are used to
uniquely identify hosts on a local network.
8.
B, F. The ISO wanted all vendors equipment to be able to work
together, which is the main reason for the OSI model. The second and
last options are saying the same thing.
9.
B. The best answer for this question is the second option. Full duplex
cannot run over 10Base2; you cannot connect multiple nodes to a sin-
gle switch port and run full duplex; and cut-through has nothing to do
with half- or even full-duplex Ethernet.
10.
D. Flow control stops a device from overflowing its buffers. Even
though flow control can be used at many layers, the Transport layer's
reliable connection provides the best flow control available in the
model.
11.
B. The only layer of the OSI model that can actually change data is
the Presentation layer.
12.
C. The encapsulation method is: data, segment, packet, frame, bit.
13.
C. The largest advantage of a layered model is that it can allow appli-
cation developers to change the aspects of a program in just one layer
of the layer model's specifications.
Copyright ©2002 SYBEX, Inc., Alameda, CA
www.sybex.com