Cn_rev

D. Fiber optic cable provides a more secure, long-distance cable that is not susceptible to EMI
interference at high speeds.

C. The encapsulation method is: data, segment, packet, frame, bit.

D. The Transport layer receives large data streams from the upper layers and breaks these up
into smaller pieces called segments.

C. A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted
and received reliably. A reliable connection is defined by a virtual circuit that uses
acknowledgments, sequencing, and flow control, which are characteristics of the Transport
layer (layer 4).

C. Protocol Data Units are used to define data at each layer of the OSI model. PDUs at the Network
layer are called packets.

. The only layer of the OSI model that can change data is the Presentation layer.

C. The first three bytes of a hardware (MAC) address are considered the OUI portion and identify
the manufacturer of the card. This code, which is assigned by the IEEE, is called the organizationally
unique identifier (OUI). The first three bytes are C9-3F-32, which is 11001001-
00111111-00110010 in binary.

B, C, D, F, G, H. Although Bill Gates is a good answer for me, the answers are: not enough
bandwidth, too many users, broadcast storms, multicasting, adding hubs for connectivity to the
network, and a large amount of ARP or IPX traffic.

A, D. The main advantage of a layered model is that it can allow application developers to
change aspects of a program in just one layer of the layer model’s specifications. Advantages of
using the OSI layered model include, but are not limited to, the following: It divides the network
communication process into smaller and simpler components, thus aiding component development,
design, and troubleshooting; allows multiple-vendor development through standardization
of network components; encourages industry standardization by defining what functions
occur at each layer of the model; allows various types of network hardware and software to
communicate; and prevents changes in one layer from affecting other layers, so it does not hamper
development.

C. 802.11b, also called “Wi-Fi,” has a maximum data rate of 11Mbps.

18. C. Once transmitting stations on an Ethernet segment hear a collision, they send an extended
jam signal to ensure that all stations recognize the collision. After the jamming is complete, each
sender waits a predetermined amount of time, plus a random time. After both timers expire, they
are free to transmit.

17. B, D. Routers, by default, break up broadcast domains, which means that broadcasts sent on
one network would not be forwarded to another network by the router.

B, C. Bridges break up collision domains, which allows more bandwidth for users.

B, C, E. Hubs cannot run full-duplex Ethernet. Full duplex must be used on a point-to-point
connection between two devices capable of running full duplex. Switches and hosts can run full
duplex between each other.

A, C, E, G. Routers provide packet switching, packet filtering, internetwork communication,
and path selection.

A, D. An Ethernet frame has source and destination MAC addresses, an Ether-Type field to
identify the Network layer protocol, the data, and the FCS field that holds the result of the CRC.

A, D. Unlike full duplex, half-duplex Ethernet operates in a shared collision domain, and it has
a lower effective throughput then full duplex.

A, C, D. The common types of flow control are buffering, windowing, and congestion avoidance.

19. B, C. No collision on a point-to-point full-duplex Ethernet segment should occur, and fullduplex
Ethernet should be faster then half-duplex Ethernet.

C, D. A MAC address is 6 bytes long (48 bits) and is burned into the NIC card by the manufacturer.
IPX, when it was still used, used the MAC address as part of the configuration.