Form Authentication

1. Connectivity is a concept related to 1. ? transmitting information, either by computer or by phone 2. NO the interconnections within a computer 3. YES using computer networks to link people and resources 4. ? being in an active session with your computer 2. One of the most dramatic changes in connectivity and communications in the past five years or so has been ____. 1. ? mobile or wireless telephones 2. NO public and private discussion 3. NO satellite uplinks 4. NO running programs on remote computers 3. The four basic elements of any communication system include 1. ? peer-to-peer, videoconferencing, online photo-conferencing, net optical 2. YES sending and receiving devices, communication channel, connection device, and data transmission specifications 3. ? telephone lines, coaxial cables, fiber-optics cables, and communication channel 4. ? software, hardware, communication channel, network 4. These communication devices originate as well as accept messages in the form of data, information, and/or instructions. 1. ? i-drives 2. YES sending and receiving devices 3. ? key chain drives 4. ? optical drives 5. The transmission medium that carries the message is referred to as the 1. ? send and receive device 2. YES communication channel 3. ? protocol 4. ? gateways 6. Data is transmitted using light through a ____ cable. 1. ? twisted pair 2. YES fiber-optic 3. ? coaxial 4. ? microwave 7. Which physical connection is the fastest? 1. ? twisted pair 2. ? coaxial cable 3. YES fiber-optics 4. NO microwaves 8. Which of the following connection methods would not be used to connect devices between two different offices? 1. NO twisted pairs 2. NO fiber-optics 3. NO coaxial cables 4. ? infrared 9. Most Web-enabled devices follow a standard known as 1. ? FireWire 2. ? Bluetooth 3. NO TCP/IP 4. YES Wi-FI 10. This wireless standard is widely used to connect computers to each other and to the Internet. 1. YES 802.11 2. ? RJ45 3. ? Blueband 4. ? Broadband

11. Bluetooth is a type of radio wave information transmission system that is good for about 1. YES 30 feet 2. NO 30 yards 3. ? 30 miles 4. ? 300 miles 12. A term relating to sending data to a satellite is 1. YES uplink 2. ? downlink 3. ? modulate 4. ? demodulate 13. A credit card-sized expansion board that is inserted into portable computers that connects the PC to the telephone wall jack is called what? 1. ? Internal modem 2. ? External modem 3. YES PC Card modem 4. ? Wireless modem 14. Standard telephone lines and conventional modems provide what is called 1. ? Bluetooth service 2. YES dial-up service 3. ? wireless service 4. ? WiFI service 15. Special high-speed lines used by large corporations to support digital communications are known as 1. ? satellite/air connection service lines 2. ? cable modems 3. ? digital subscriber lines 4. YES T1, T2, T3 and T4 lines 16. The rules for exchanging data between computers are called 1. ? interconnections 2. ? synchronous packages 3. YES protocols 4. ? data transmission synchronization 17. Each computer on the Internet has a unique numeric address called a(n) 1. ? domain address 2. ? protocol address 3. YES IP address 4. ? Web address 18. ____ is the process of breaking down information sent or transmitted across the Internet into small parts called packets. 1. ? protocol 2. ? bandwidth 3. YES reformatting 4. ? identification 19. Two or more computers connected so that they can communicate with each other and share information is called a 1. ? satellite 2. ? protocol 3. ? broadcast 4. YES network 20. Any device that is connected to a network is called a 1. ? client 2. YES node 3. ? server 4. ? manager

Telephone systems may be classified as: Your Answer: duplex and symmetrical. 2. A network that provides a constant bandwidth for the complete duration of a message transfer is a: Your Answer: cell switched network. Correct Answer: circuit switched network. Consider the nature of the path between each station. 3. A router: Your Answer: forwards a packet to all outgoing links. Correct Answer: determines on which outgoing link a packet is to be forwarded. In general a router only forwards a packet to a single outgoing link. 4. The Internet is an example of a: Your Answer: circuit switched network. Correct Answer: packet switched network. Circuit switching provides continuous transmission and cell switching assumes 'packets' are of uniform length. 5. A data link between the head office of a financial organization and one of its branches runs continuously at 2.048 Mbps. Between the hours of 0900 and 1700 it is noted that there are 295 bits received in error. Determine the bit error rate. Your Answer: 5 x 10-8 Correct Answer: 5 x 10-9 BER is simply the ratio of error'ed bits to the total number of bits sent. 6. The optical fibre trans-Atlantic cable TAT-14 includes a section from Bude, Cornwall to Tuckerton, New Jersey. Determine the propagation delay if the route length is 6,254 km. Your Answer: 312.7 ms. Correct Answer: 31.27 ms. Assume a velocity of propagation of 2 x 108 ms-1. 7. A file is downloaded to a home computer using a 56 kbps modem connected to an Internet Service Provider. If the download completes in 2 minutes, estimate the maximum size of data downloaded.

Your Answer: 13.44 Mbit. Correct Answer: 6.72 Mbit. Data rate is the ratio of data to be transferred to time taken. 8. Baseband transmission may be defined as the transmission of a signal over a link: Your Answer: which is relatively short. Correct Answer: without any change in frequency. 9. Skin effect may be described as: (Note: more than one answer is correct.)

Your Answer: conduction restricted to the outer layer of a conductor. Correct Answers: conduction restricted to a small central region of a conductor. conduction restricted to the outer layer of a conductor. 10. A block of data consisting of 2048 bits is transmitted between two computers interconnected by 450 m of twisted-pair wire. If the transmission rate is 34 kbps determine a, the ratio of propagation delay to transmission delay. Your Answer: 37.6 x 10-6 11. Asynchronous transmission may be defined as: Your Answer: communication where receiver will operate satisfactorily, even if its clock frequency is appreciably different to that of the transmitter. Correct Answer: communication where the receiver clock must be in approximate synchronism with that of the transmitter. 12. Synchronous transmission may be defined as: Your Answer: communication where the receiver will operate satisfactorily, even if its clock frequency is appreciably different to that of the transmitter. Correct Answer: communication where the receiver clock is arranged to be in exact synchronism with that of the receiver. 13.

Manchester encoding is principally designed to: Your Answer: increase the bandwidth of a signal transmitted on the medium. Correct Answer: ensure that a transition occurs in the centre of each bit period. 14. Is the following statement true of the Go-back-N error control strategy? A transmitter may send up to N packets before it receives an acknowledgment.

Your Answer: False Correct Answer: True Suppose N equals 7 and that packet 3 has just been acknowledged. The transmitter may send 7 packets without waiting for any further acknowledgement, i.e. packet numbers 4, 5, 6, 7, 0 (remember modulo-8 in this example), 1 and 2. 15. A protocol data unit (PDU) is exchanged between the same layer in two separate protocol stacks. It comprises the PDU passed from the layer immediately above and its own protocol control information. Your Answer: False Correct Answer: True Which of the following operate at the presentation layer? A . MIDI E . JPEG B. TIFF D. MPEG E. GIF Correct! The network layer uses logical addresses to route data What are the sublayers of the data link layer? MAC and LLC Which layer translates between physical (MAC) and logical addresses? Network Correct! Hardware (MAC) addresses are (except in rare instances) preset at the factory. Logical addresses are configured by a network administrator. Which layer translates between physical and logical addresses? network Correct! The Media Access Control (MAC) sublayer handles protocol access to the physical medium. The Logical Link Control (LLC) sublayer acts as an interface between the upper layers and the lower layers, handing things off to the MAC sublayer. This is where timing and flow control takes place. Which layer is responsible for packet sequencing, acknowledgments, and requests for retransmission? transport