Interview questions and answers

1.	How many digits of the DNIC (Data Network Identification Code) identify the country?
	A. first three B. first four C. first five D. first six E. None of the above Answer: Option A.

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2.	A station in a network forwards incoming packets by placing them on its shortest output queue. What routing algorithm is being used?
	A. hot potato routing B. flooding C. static routing D. delta routing E. None of the above Answer: Option A

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3.	The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to
	A. 0.003 B. 0.009 C. 0.991 D. 0.999 E. None of the above

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4.	Frames from one LAN can be transmitted to another LAN via the device
	A. Router B. Bridge C. Repeater D. Modem Answer: Option B

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5.	Which of the following condition is used to transmit two packets over a medium at the same time?
	A. Contention B. Collision C. Synchronous D. Asynchronous E. None of the above Answer: Option B
6.	You have a class A network address 10.0.0.0 with 40 subnets, but are required to add 60 new subnets very soon. You would like to still allow for the largest possible number of host IDs per subnet. Which subnet mask should you assign?
	A. 255.240.0.0 B. 255.248.0.0 C. 255.252.0.0 D. 255.254.0.0 E. 255.255.255.255 Answer: Option D

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7.	What are the most commonly used transmission speeds in BPS used in data communication?
	A. 300 B. 1200 C. 2400 D. 9600 E. None of the above Answer: Option D

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8.	What is the default subnet mask for a class C network?
	A. 127.0.0.1 B. 255.0.0.0 C. 255.255.0.0 D. 255.255.255.0 E. None of the above Answer: Option D

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9.	Which of the following is used for modulation and demodulation?
	A. modem B. protocols C. gateway D. multiplexer E. None of the above Answer: Option A

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10.	Which of the following is not a disadvantage of wireless LAN?
	A. Slower data transmission B. higher error rate C. interference of transmissions from different computers D. All of the above Answer: Option D
11.	The Internet Control Message Protocol (ICMP)
	A. allows gateways to send error a control messages to other gateways or hosts B. provides communication between the Internet Protocol Software on one machine and the Internet Protocol Software on another C. only reports error conditions to the original source, the source must relate errors to individual application programs and take action to correct the problem D. All of the above E. None of the above Answer: Option D

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12.	Your company has a LAN in its downtown office and has now set up a LAN in the manufacturing plant in the suburbs. To enable everyone to share data and resources between the two LANs, what type of device(s) are needed to connect them? Choose the most correct answer.
	A. Modem B. Cable C. Hub D. Router Answer: Option D

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13.	The term 'duplex' refers to the ability of the data receiving stations to echo back a confirming message to the sender. In full duplex data transmission, both the sender and the receiver
	A. cannot talk at once B. can receive and send data simultaneously C. can send or receive data one at a time D. can do one way data transmission only E. None of the above Answer: Option B

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14.	How many hosts are attached to each of the local area networks at your site?
	A. 128 B. 254 C. 256 D. 64 E. None of the above Answer: Option B

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15.	Which of the following technique is used for fragment?
	A. a technique used in best-effort delivery systems to avoid endlessly looping packets B. a technique used by protocols in which a lower level protocol accepts a message from a higher level protocol and places it in the data portion of the low level frame C. one of the pieces that results when an IP gateway divides an IP datagram into smaller pieces for transmission across a network that cannot handle the original datagram size D. All of the above E. None of the above Answer: Option C
16.	Contention is
	A. One or more conductors that serve as a common connection for a related group of devices B. a continuous frequency capable of being modulated or impressed with a second signal C. the condition when two or more stations attempt to use the same channel at the same time D. a collection of interconnected functional units that provides a data communications service among stations attached to the network E. None of the above Answer: Option C

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17.	Avalanche photodiode receivers can detect hits of transmitted data by receiving
	A. 100 photons B. 200 photons C. 300 photons D. 400 photons E. None of the above Answer: Option B

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18.	Satellite-Switched Time-Division Multiple Access (SS/TDMA) is
	A. the method of determining which device has access to the transmission medium at any time. B. a medium access control technique for multiple access transmission media C. a form of TDMA in which circuit switching is used to dynamically change the channel assignments D. All of the above E. None of the above Answer: Option C

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19.	When you ping the loopback address, a packet is sent where?
	A. On the network B. Down through the layers of the IP architecture and then up the layers again C. Across the wire D. through the loopback dongle E. None of the above Answer: Option B

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20.	Which of the following TCP/IP protocol is used for transferring electronic mail messages from one machine to another?
	A. FTP B. SNMP C. SMTP D. RPC E. None of the above Answer: Option C
21.	Which of the following device is used to connect two systems, especially if the systems use different protocols?
	A. hub B. bridge C. gateway D. repeater E. None of the above Answer: Option C

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22.	The synchronous modems are more costly than the asynchronous modems because
	A. they produce large volume of data B. they contain clock recovery circuits C. they transmit the data with stop and start bits. D. they operate with a larger bandwidth E. None of the above Answer: Option B

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23.	A distributed network configuration in which all data/information pass through a central computer is
	A. bus network B. star network C. ring network D. Point-to-point network E. None of the above Answer: Option B

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24.	Which of the following TCP/IP protocol allows an application program on one machine to send a datagram to an application program on another machine?
	A. UDP B. VMTP C. X.25 D. SMTP E. None of the above Answer: Option A

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25.	A remote batch-processing operation in which data is solely input to a central computer would require a:
	A. telegraph line B. simplex lines C. mixedband channel D. All the above E. None of the above Answer: Option B
26.	ICMP (Internet Control Message Protocol) is
	A. a TCP/IP protocol used to dynamically bind a high level IP Address to a low-level physical hardware address B. a TCP/IP high level protocol for transferring files from one machine to another C. a protocol used to monitor computers D. a protocol that handles error and control messages E. None of the above Answer: Option D

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27.	If you get both local and remote echoes, every character you type will appear on the screen
	A. once B. twice C. three times D. never E. None of the above Answer: Option B

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28.	What part of 192.168.10.51 is the Network ID, assuming a default subnet mask?
	A. 192 B. 192.168.10 C. 0.0.0.5 D. 51 E. None of the above Answer: Option B

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29.	The slowest transmission speeds are those of
	A. twisted-pair wire B. coaxial cable C. fiber-optic cable D. microwaves Answer: Option A

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30.	A noiseless 3 KHz Channel transmits bits with binary level signals. What is the maximum data rate?
	A. 3 Kbps B. 6 Kbps C. 12 Kbps D. 24 Kbps. Answer: Option B
31.	Carrier is
	A. One or more conductors that serve as a common connection for a related group of devices B. a continuous frequency capable of being modulated or impressed with a second signal C. the condition when two or more sections attempt to use the same channel at the same time D. a collection of interconnected functional units that provides a data communications service among stations attached to the network E. None of the above Answer: Option B

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32.	What can greatly reduce TCP/IP configuration problems?
	A. WINS Server B. WINS Proxy C. DHCP Server D. PDC E. None of the above Answer: Option C

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33.	In CRC there is no error if the remainder at the receiver is _____.
	A. equal to the remainder at the sender B. zero C. nonzero D. the quotient at the sender Answer: Option B

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34.

Which of the following statements is correct for the use of packet switching?

A. the subdivision of information into individually addressed packets in conjunction with alternative routing arrangement enabled the transmission path to be altered in the event of congestion or individual link failure B. the employment of additional intelligence within the network enabled more sophisticated error control and link control procedures to be applied C. by employing wide bandwidth circuits for the trunk networks substantial economies through extensive sharing of capacity could be achieved. D. All of the above E. None of the above Answer: Option D

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35.	A front-end processor is
	A. a user computer system B. a processor in a large-scale computer that executes operating system instructions C. a minicomputer that relieves main-frame computers at a computer centre of communications control functions D. preliminary processor of batch jobs. E. None of the above Answer: Option C
36.	What is the port number for NNTP?
	A. 119 B. 80 C. 79 D. 70 Answer: Option A

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37.	Eight stations are competing for the use of a shared channel using the 'Adaptive tree Walk Protocol'. If the stations 7 and 8 are suddenly become ready at once, how many bit slots are needed to resolve the contention?
	A. 7 slots B. 5 slots C. 10 slots D. 14 slots Answer: Option A

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38.	Usually, it takes 10-bits to represent one character. How many characters can be transmitted at a speed of 1200 BPS?
	A. 10 B. 12 C. 120 D. 1200 E. None of the above Answer: Option C

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39.	To connect a computer with a device in the same room, you might be likely to use
	A. a coaxial cable B. a dedicated line C. a ground station D. All of the above E. None of the above Answer: Option A

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40.	Internet-like networks within an enterprise.
	A. Intranets B. Switching alternating C. Inter organizational networks D. Extranets Answer: Option A
41.	How many bits internet address is assigned to each host on a TCP/IP internet which is used in all communications with the host?
	A. 16 - bits B. 32 - bits C. 48 - bits D. 64 - bits E. None of the above Answer: Option B

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42.	With an IP address of 100, you currently have 80 subnets. What subnet mask should you use to maximize the number of available hosts?
	A. 192 B. 224 C. 240 D. 248 E. 252 Answer: Option E

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43.	Which of the following types of channels moves data relatively slowly?
	A. wideband channel B. voiceband channel C. narrowband channel D. broadband channel E. None of the above Answer: Option C

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44.	Which of the following is required to communicate between two computers?
	A. communications software B. protocol C. communications hardware D. access to transmission medium E. All of the above Answer: Option E

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45.	Which of the following does not allow multiple users or devices to share one communications line?
	A. doubleplexer B. multipplexer C. concentrator D. controller E. None of the above Answer: Option A
46.	The geostationary satellite used for communication systems
	A. rotates with the earth B. remains stationary relative to the earth C. is positioned over equator D. All of the above E. None of the above Answer: Option D

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47.	Telecommunication networks frequently interconnect an organization with its customers and suppliers. Select the best fit for answer:
	A. Bandwidth alternatives B. Switching alternating C. Inter organizational networks D. Extranets Answer: Option C

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48.	The packets switching concept was first proposed
	A. in the late 1980s for the Defense Ministry of US. B. in the early 1960s for military communication systems, mainly to handle speech C. in the late 1950s for Defense Ministry of US D. All of the above E. None of the above Answer: Option B

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49.	The _____ houses the switches in token ring.
	A. transceiver B. nine-pin connector C. MAU D. NIC E. None of the above Answer: Option C

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50.	What device separates a single network into two segments but lets the two segments appear as one to higher protocols?
	A. Switch B. Bridge C. Gateway D. Router Answer & Explanation Answer: Option B

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