Internetworking Questions and Answers

Answer: D

Correct answer: Fiber-optic cable

Fibre carries light rather than current, so it neither radiates interference nor picks any up, and it is completely immune to electromagnetic interference and to the ground potential differences that trouble copper between buildings. Coaxial cable and shielded twisted pair reduce interference; only fibre is genuinely unaffected by it.

Answer: B

You must be able to take a binary number and convert it into both decimal and hexadecimal. To convert to decimal, just add up the 1s using their values. The values that are turned on with the binary number of 10110111 are 128 + 32 + 16 + 4 + 2 + 1 = 183. To get the hexadecimal equivalent, you need to break the eight binary digits into nibbles (4 bits), 1011 and 0111. By add- ing up these values, you get 11 and 7. In hexadecimal, 11 is B, so the answer is 0xB7.

Answer: B

Correct answer: 2 and 3

A bridge divides a network into separate collision domains, so stations on either side no longer contend with each other, which gives each segment its own share of the bandwidth. A bridge forwards broadcasts, so it does not divide the broadcast domain - that requires a router.

Answer: 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).

Answer: B

Routers operate at layer 3. LAN switches operate at layer 2. Ethernet hubs operate at layer 1. Word processing applications communicate to the Application layer interface, but do not operate at layer 7, so the answer would be none.

Answer: C

Correct answer: 3 and 4

A hub and a repeater both work at the physical layer: they regenerate and retime the signal so it can travel further, extending the reach of a single segment without dividing it. A switch is a layer 2 device and creates separate collision domains rather than enlarging one; a network card is an endpoint; and a transceiver converts between media rather than extending the distance.

Answer: C

Correct answer: 1 and 4

Half-duplex Ethernet cannot send and receive at once, so every station shares one collision domain and must use CSMA/CD to detect and recover from collisions. Full duplex has a separate path each way, so collisions cannot occur and collision detection is switched off.

Answer: A

Full-duplex means you are using both wire pairs simultaneously to send and receive data. You must have a dedicated switch port for each node, which means you will not have collisions. Both the host network card and the switch port must be capable and set to work in full-duplex mode.

Answer: D

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, but a hub can never run full duplex.

Answer: D

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, but they must make sure the media is clear before transmitting and that they all have equal priority.