Assignment 1

Total of 50 marks. Answer the following questions. For multiple-choice questions, circle the letter of the best response. For completion (fill-in-the-blank) questions, write the word(s) that best complete the sentence.

Treat this assignment as an open-book individual exam. You may consult any of your class notes or other books or documents, paper or electronic. However, you may NOT discuss questions or share answers with any other person until after the assignment is due.

1. Getting a packet from the source to destination through several connected networks is known as ______________.
2. Simple parity checking can NOT detect
   1. an odd number of errors.
   2. an even number of errors.
   3. more than one error.
   4. any errors.
3. Which is true about synchronous and asynchronous connections?
   1. Asynchronous transmissions are generally used for large amounts of data.
   2. Asynchronous transmissions are often combined with a clock signal.
   3. Synchronous transmissions require synchronisation bits at the end.
   4. Synchronous transmissions have a larger overhead than asynchronous transmissions.
4. What will happen if a receiver confirms receipt of a message but the confirmation is lost before it reaches the sender?
   1. ACK
   2. NAK
   3. ready
   4. resend
   5. timeout
5. Which type of serial connection will generally have the highest performance?
   1. simplex
   2. half-duplex
   3. full-duplex
   4. multiplex
6. A parallel cable must be short because over a long distance the signals on the wires can become out of sync. This is known as ______________.
7. A modem converts from __________________ to __________________ signals when sending data from a computer to an older telephone line. [2]
8. Which type of multiplexing uses a round robin scheme?
   1. Time division multiplexing
   2. Frequency division multiplexing
   3. Statistical multiplexing
9. Which of the following would NOT generally improve data transmission on cables?
   1. Using shorter cables
   2. Using shielding or insulation
   3. Using a medium with low electrical resistance
   4. Decreasing the number of cable twists per metre
10. Which category of UTP cable can be used for both Ethernet and Fast Ethernet? ___________________
11. Which type of connector is most commonly used for LANs?
    1. D
    2. BNC
    3. RJ-11
    4. RJ-45
12. How many pairs of wires are in most UTP cables used today? ______________
13. What is the most important difference between the Internet and an Intranet?
    1. the number of users who have access
    2. the geographical distances covered
    3. the network protocols used
    4. the network software used
14. Which is NOT an advantage of client-server networks over peer-to-peer networks?
    1. centralised administration
    2. initial investment
    3. performance
    4. strong user-based security
15. Which of these peripherals is NOT generally shared on the network?
    1. printer
    2. hard disk
    3. modem
    4. monitor
16. Which workstation operating system has built-in network server capabilities?
    1. Windows for Workgroups 3.11
    2. Windows NT Workstation
    3. Windows 2000 Professional
    4. Linux
17. The way that two different devices are connected is the
    1. interface
    2. medium
    3. protocol
    4. topology
18. A signal transmitting at 2.5 MHz can encode 8 bits per cycle. What is the bandwidth of the signal? _________________
19. Which type of network topology requires the least amount of cable?
    1. bus
    2. mesh
    3. ring
    4. star
20. Which type of server lists many types of resources available on the network?
    1. file
    2. directory
    3. print
    4. mail
21. Which is NOT generally a result of installing a network?
    1. increased peripheral cost
    2. need for administrator
    3. organisational changes
    4. security holes to plug
22. What type of device is used to lengthen a LAN size by strengthening the signal?
    1. bridge
    2. gateway
    3. repeater
    4. router
23. In order to make content available on the Internet you need to use a
    1. web browser
    2. web client
    3. web page
    4. web server
24. Which of the following can NOT get you connected to the Internet?
    1. an Internet café
    2. an Internet or online service provider
    3. an isolated local area network
    4. a standalone computer with a modem
25. A disadvantage of protocols is that they tend to limit
    1. communication
    2. innovation
    3. interconnection
    4. standardisation
26. Which type of network was NOT originally standardised by the IEEE 802 committee because of speed?
    1. FDDI
    2. MAN
    3. token bus
    4. token ring
    5. wireless
27. Which OSI layer is primarily responsible for the following tasks?
    1. displaying a retrieved web page in a web browser _________________
    2. getting a message from the sender's LAN to the receiver's LAN _________________
    3. retransmitting after detecting a collision on a LAN _________________
    4. passing a token to the next workstation ___________________
    5. the sender breaking a long message into pieces _________________
    6. the receiver reassembling the pieces in the right order _________________
    7. specifying the number and voltage of pins for a cable connector ________________
    8. software to read USENET newsgroups ________________
    9. translating between bits of information and electronic signals _______________
    10. displaying the user's original message, exactly as it was sent _______________
28. Which will most reduce the quality of analog data to be sent on a network?
    1. long sampling period
    2. many bits per sample
    3. mpeg compression
    4. non-linear digitising
29. Which type of modulation is likely to be most adversely affected by resistance during transmission over long distances?
    1. amplitude
    2. frequency
    3. phase
30. Which type of noise is likely to be a problem on a LAN with thick co-axial cable and properly functioning terminators?
    1. impulse noise
    2. cross-talk
    3. echo
    4. white noise
31. What percent overhead would be used to perform both vertical and longitudinal redundancy checks on just two bytes of data? [2]
32. Which type of error correction is most commonly used at the end of message packets in popular OSI model compliant network protocols?
    1. vertical redundancy check
    2. longitudinal redundancy check
    3. cyclical redundancy check
    4. checksum
33. Which is NOT a reason why forward error correction is rarely used in data communication and networking?
    1. Few forward error correction algorithms have been invented
    2. Sending the data to reconstruct the message would be a large overhead
    3. The amount of processing required to reconstruct the message would be large
    4. The error correction data could itself be damaged
    5. It is faster and easier to just resend the data
34. Which is NOT a general characteristic of connectionless protocols?
    1. Used for high data rates
    2. High error rates are common
    3. Performed at lower OSI levels
    4. Used in LANs
35. How are the RTS and CTS pins of a V.24 modem interface commonly used?
    1. transmitting data
    2. flow control
    3. error checking
    4. unused
36. Which indicator light on an external modem would tell you that your dial-up connection has succeeded?
    1. DSR
    2. Ground
    3. CD
    4. DTR
37. The letter A is represented the same in ASCII and EBCDIC except for the
    1. least significant bit
    2. most significant bit
    3. parity bit
    4. start bit
38. The purpose of a preamble is
    1. to delimit the start of the data
    2. to make the packet meet the minimum length requirement
    3. to provide synchronisation
    4. to provide error checking
39. The purpose of bit stuffing in HDLC synchronisation is
    1. to detect errors in the data
    2. to distinguish the data from the start and end of the message
    3. to make the message have the required length
    4. to make start and stop flags composed of long strings of 1s or 0s