Washburn University



Name: __________________________ Date: _____________

|1. |As part of the five-layer network model used in this textbook, the data link layer sits directly between: |

|A) |the operational and the application layers |

|B) |the network and the application layers |

|C) |the network and transport layers |

|D) |the physical and the application layers |

|E) |the physical and the network layers |

|2. |Which of the following is true with respect to the data link layer? |

|A) |It accepts streams of bits from the application layer. |

|B) |It is responsible for getting a message from one computer to another (one node to another) without errors. |

|C) |It accepts messages from the physical layer. |

|D) |It performs routing functions. |

|E) |It organizes data from the physical layer and passes these coherent messages to the application layer. |

|3. |____________ is not a function of a data link protocol. |

|A) |Media access control |

|B) |Message delineation |

|C) |Amplitude shift keying |

|D) |Indicating when a message starts and stops |

|E) |Error control |

|F) |802.11g |

|4. |Media access control: |

|A) |is not very important in point-to-point with full duplex configuration |

|B) |is not very important in local area networks |

|C) |is not very important in a point-to-point with a half duplex configuration |

|D) |is not very important in a multipoint configuration |

|E) |does not control when computers transmit |

|5. |Which of the following is not a controlled access method of media access control? |

|A) |Token access |

|B) |CSMA/CD |

|C) |polling |

|D) |roll call polling |

|E) |hub polling |

|6. |________ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive. |

|A) |Contention |

|B) |Polling |

|C) |Pooling |

|D) |Carrier sense |

|E) |CRC |

|7. |Which of the following is true about roll call polling? |

|A) |It can not be modified to increase priority of clients or terminals. |

|B) |It does not require a server or host or special device that performs the polling. |

|C) |It is also called token passing. |

|D) |It is a type of contention approach to media access control. |

|E) |It typically involves some waiting because the front-end processor or server has to wait for a response from the polled |

| |client or terminal. |

|8. |With contention: |

|A) |computers wait until the circuit is free before they send data |

|B) |the server or front end processor works consecutively through a list of clients to determine who should have access to the|

| |media |

|C) |the front end processor must wait for a response from the polled client or terminal |

|D) |one computer starts the poll and passes it to the next computer on the multipoint circuit |

|E) |there is never a chance for “collision,” or two computers trying to send data at the same time |

|9. |In general, controlled approaches: |

|A) |work better than contention approaches for small networks that have low usage |

|B) |work better than contention approaches for large networks that have high usage |

|C) |work better than contention approaches for all sizes of networks |

|D) |do not require a host, server, or active monitor to assign media access control |

|E) |have many collisions |

|10. |In a _________ , more than one data bit is changed by the error-causing condition. |

|A) |burst error |

|B) |data rate shift |

|C) |Trellis-coded modulation |

|D) |uniform distribution |

|E) |amplitude key shift |

|11. |Errors on a network can occur: |

|A) |only on dial-up type of circuits |

|B) |because of noise on the line |

|C) |only on poorly maintained networks |

|D) |only due to Gaussian noise |

|E) |only due to lightning strikes |

|12. |In a dial-up network: |

|A) |the error rate will vary because the circuits will change with each dial-up |

|B) |the network is less prone to errors than private dedicated lines |

|C) |users might try to transmit the data at a higher speed to decrease the error rate |

|D) |constant transmission conditions will always create a constant error rate |

|E) |users might try to transmit the data at a lower speed to speed up the data transmission |

|13. |Which of the following media is least susceptible to noise? |

|A) |fiber optic cable |

|B) |coaxial cable |

|C) |twisted pair |

|D) |unshielded twisted pair |

|E) |shielded twisted pair |

|14. |Optical media is: |

|A) |more likely to suffer from noise than electrical media |

|B) |has about the same likelihood of suffering from noise as electrical media |

|C) |has about the same likelihood of suffering from noise as coaxial cable |

|D) |less likely to suffer from noise than electrical media |

|E) |more prone to noise than twisted pair media |

|15. |____________ refers to bits that have been changed, in error, from 1 to 0, or vice versa, in a data transmission. |

|A) |Contracted bits |

|B) |Polled bits |

|C) |Inverse multiplexed bits |

|D) |Flipped bits |

|E) |Bit delineation |

|16. |Another term for impulse noise is: |

|A) |Gaussian noise |

|B) |spikes |

|C) |attenuation |

|D) |cross-talk |

|E) |intermodulation noise |

|17. |The familiar background static on radios and telephones is called: |

|A) |echoes |

|B) |intermodulation noise |

|C) |line outages |

|D) |cross-talk |

|E) |white noise |

|18. |The primary source of error in data communications is: |

|A) |echoes |

|B) |intermodulation noise |

|C) |spikes |

|D) |jitter |

|E) |cross-talk |

|19. |__________can obliterate a group of bits, causing a burst error. |

|A) |Crosstalk |

|B) |Attenuation |

|C) |Impulse noise |

|D) |Intermodulation noise |

|E) |Jitter |

|20. |Cross-talk: |

|A) |occurs when one circuit picks up signals in another |

|B) |is always bothersome because it has a high signal strength |

|C) |decreases with increased proximity of two wires |

|D) |decreases during wet or damp weather |

|E) |increases with lower frequency signals |

|21. |When a signal is reflected back to the transmitting equipment, it is called a(n) _________. |

|A) |jitter |

|B) |echo |

|C) |crosstalk |

|D) |attenuation |

|E) |impulse noise |

|22. |The loss of power a signal suffers as it travels from the transmitting computer to a receiving computer is: |

|A) |jitter |

|B) |spiking |

|C) |attenuation |

|D) |intermodulation noise |

|E) |echo |

|23. |If a signal with a frequency of 500 MHz combines with a another signal of 1500 MHz and they form a new signal of 2000 MHz; this |

| |is an example of: |

|A) |intermodulation noise |

|B) |attenuation |

|C) |echo |

|D) |jitter |

|E) |harmonic distortion |

|24. |When the output signal from an amplifier on a circuit is different from the input signal, this is called _________________. |

|A) |intermodulation noise |

|B) |attenuation |

|C) |echo |

|D) |jitter |

|E) |harmonic distortion |

|25. |A phase hit is likely to be: |

|A) |spikes |

|B) |a short term shift out of phase |

|C) |intermodulation noise |

|D) |white noise |

|E) |Gaussian noise |

|26. |_____________ is an effective way to prevent impulse noise, cross talk, and intermodulation noise. |

|A) |Shielding wires |

|B) |Adding fluorescent lights |

|C) |Adding repeaters to a circuit |

|D) |Adding amplifiers to a circuit |

|E) |Shorting a circuit |

|27. |_____________ is an effective way to prevent attenuation. |

|A) |Shielding wires |

|B) |Adding fluorescent lights |

|C) |Adding repeaters or amplifiers to a circuit |

|D) |Changing multiplexing techniques |

|E) |Shorting a circuit |

|28. |Which of the following is way to reduce or eliminate crosstalk on a circuit, |

|A) |changing multiplexing techniques |

|B) |adding repeaters or amplifiers to a circuit |

|C) |reducing the length of the cable |

|D) |adding fluorescent lights |

|E) |shorting a circuit |

|29. |On digital circuits, we use _________ to increase the strength of the signal and prevent attenuation. |

|A) |amplifiers |

|B) |repeaters |

|C) |multiplexers |

|D) |digitizers |

|E) |modems |

|30. |Which of the following is not an error detection method used in the data link layer? |

|A) |parity checking |

|B) |cyclic redundancy checking |

|C) |CRC-32 |

|D) |pulse code checking |

|E) |polynomial checking |

|31. |With odd parity (assume that the parity bit (in bold) has been placed at the end of each of the following) and a 7-bit ASCII |

| |code, which of the following is incorrect? |

|A) |01101011 |

|B) |00011011 |

|C) |00100101 |

|D) |10110110 |

|E) |11111110 |

|32. |The probability of detecting an error, given that one has occurred, using parity checking is about: |

|A) |100% |

|B) |0% |

|C) |50% |

|D) |75% |

|E) |98% |

|33. |Using parity, the probability for detecting an error, given that one has occurred, is: |

|A) |about 50% for either even or odd parity |

|B) |about 70% for even parity and 30% for odd parity |

|C) |about 30% for even parity and 70% for odd parity |

|D) |about 0% for either even or odd parity |

|E) |about 100% for either even or odd parity |

|34. |The probability of detecting an error, provided that one has occurred, using cyclic redundancy checking is about: |

|A) |75% |

|B) |0% |

|C) |exactly 100% |

|D) |50% |

|E) |> 99% |

|35. |ARQ means that: |

|A) |a receiver that detects an error in a message simply asks the sender to retransmit the message until it is received |

| |without error |

|B) |the common carrier Automatically Returns Queries to the subscriber upon receipt of such queries |

|C) |a sender is using a data link protocol called Asynchronous Repeating reQuest |

|D) |a fiber optic cable meets the American Registered Quality, a certification standard for use in high-quality data |

| |communication transmission lines |

|E) |a sender is using a parity scheme called Array Resource Quality |

|36. |In ARQ, a NAK: |

|A) |is sent by the recipient if the message was received without error |

|B) |is sent by the sender at the same time as it sends a data packet |

|C) |is sent by the recipient if the message contains an error |

|D) |refers to non-asynchronous Kermit technique |

|E) |means that the sender should continue with sending the next message |

|37. |Stop-and-wait ARQ uses ___________ type of data flow. |

|A) |full simplex |

|B) |half complex |

|C) |full duplex |

|D) |half duplex |

|E) |full complex |

|38. |With __________ ARQ, the sender pauses for a response from the receiver to alter each message or packet of data. |

|A) |open window |

|B) |halt and be recognized (HBR) |

|C) |sliding window |

|D) |stop and wait |

|E) |continuous |

|39. |With __________ ARQ, the sender immediately sends the next message or packet of data. |

|A) |continuous |

|B) |immediate |

|C) |open window |

|D) |stop-and-wait |

|E) |halt and be recognized (HBR) |

|40. |______________ controls errors by detecting and correcting them at the receiving end without retransmission of the original |

| |message. |

|A) |Hamming code |

|B) |Huffman encoding |

|C) |Front end processing |

|D) |Wave division multiplexing |

|E) |Hub polling |

|41. |Asynchronous transmission: |

|A) |is used to transmit each character simultaneously with all other characters |

|B) |has a pre-determined, fixed time between sending characters |

|C) |is typically used on multipoint half duplex circuits |

|D) |uses a continuous series of start bits as an idle signal |

|E) |is also known as start-stop transmission |

|42. |Which of the following is not a type of asynchronous file transfer protocol? |

|A) |XMODEM-CRC |

|B) |OSCAR |

|C) |XMODEM |

|D) |XMODEM-1K |

|E) |ZMODEM |

|43. |Synchronous transmission: |

|A) |cannot be used on multipoint circuits |

|B) |is used to send one character at a time |

|C) |uses start bits before each character to be sent |

|D) |uses stop bits after each character to be sent |

|E) |is used to transmit a “frame” or “packet” of data at a time |

|44. |Which of the following is true about the data link protocol, SDLC: |

|A) |It is a client-server protocol developed by Compaq in 1996 |

|B) |It is a byte-count-oriented protocol |

|C) |It uses a special bit pattern called a flag at the beginning and end of every frame (or packet) |

|D) |It uses a contention media access control protocol |

|E) |It does not have a problem with transparency |

|45. |Which of the following is true about the data link protocol, Ethernet (IEEE 802.3)? |

|A) |it is a byte-oriented protocol |

|B) |it is a bit-oriented protocol |

|C) |it uses block check characters for error detection |

|D) |it is a byte-count oriented protocol |

|E) |it uses parity bits for error detection |

|46. |Which of the following is true about the data link protocol, PPP? |

|A) |it is a byte-oriented protocol |

|B) |it is a bit-oriented protocol |

|C) |it uses block check characters for error detection |

|D) |it is a byte-count oriented protocol |

|E) |it uses parity bits for error detection |

|47. |Which of the following is not a type of synchronous data link protocol? |

|A) |SDLC |

|B) |KERMIT |

|C) |PPP |

|D) |HDLC |

|E) |Ethernet (IEEE 802.3) |

|48. |In communication protocols, _________ are used to convey the user's meaning. |

|A) |information bits |

|B) |overhead bits |

|C) |stop bits |

|D) |start bits |

|E) |flag bits |

|49. |_________________ is defined as the total number of information bits divided by the total number of bits in the transmission. |

|A) |Asynchronous rate |

|B) |Protocol percentage |

|C) |Throughput |

|D) |Transmission Rate of Information Bits |

|E) |Transmission efficiency |

|50. |Calculating the actual throughput of a data communication network is: |

|A) |not normally required for synchronous networks because they are so fast |

|B) |complex because many factors affect throughput |

|C) |simple because packet size is the primary factor affecting throughput |

|D) |not needed for satellite-based networks |

|E) |far less complicated if the system operates on a contention basis |

|51. |TRIB, an acronym that relates to throughput, stands for: |

|A) |Throughput Reduction of Information Barriers |

|B) |Transmission Rate of Information Bits |

|C) |Throughput Rate of Iso-synchronous Bytes |

|D) |Transmission Regulation for Inverse-multiplexing Bands |

|E) |Trellis-coded Regulation of Information Bits |

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download