Data Communication and Computer Network Questions and Answers

1Which error detection method consists of a parity bit for each data unit as well as an entire data . unit of parity bits? (a) VRC (d) Checksum (b) LRC (e) None of the above. (c) CRC 2Which of the following encoding method does not provide for synchronization? . (a) NRZ-L (d) HDB3 (b) RZ (e) Manchester. (c) B8ZS 3 Shannon’s noisy channel capacity theorem states that C = H Log2( 1 + S/N) . this equation H stands for C is the bandwidth of the signal H is the bandwidth of the Channel C is the bandwidth of the Channel H is the bandwidth of the signal S/N is in decibels. bits per second. In

5When signals are used to transmit digital data Channel of infinite bandwidth must be used for 100% accurate reception of data A modulation technique must always be used The data rate is only limited by the bandwidth of the channel used Data must be decoded on to the signal at the transmitter The Noise level of the channel can increase the bandwidth. 6In go-back-n ARQ, if frames 4, 5, 6 are received successfully, What is the ACK number receiver . may send to the sender? (a) 5 (b) 6 (c) 7 (d) 8 (e) 9.

Transmitted signals across band limited channels are distorted due to External interferences. Attenuation of some of the frequency components Delays in some frequency components Reductions in the amplitudes of the transmitted frequency components Amplification of the unwanted frequency components. The following statements can be made in general on data communication links. Digital data cannot be transmitted along analog transmission links. A modem is an essential component of a serial data link. Full duplex communication is not done on serial transmission. Parallel links are used in interconnecting subsystems of a computer system. Which of the following statements are correct? and (IV) are correct, (II) and (III) are incorrect and (II) are correct, (III) and (IV) are incorrect and (IV) are correct, (I) and (III) are incorrect (II) and (III) and (IV) are correct, (I) is incorrect. (I), (II) and (III) are incorrect, (IV) is correct.

9. In a Bit Oriented Synchronous Transmission Scheme, the bit pattern 1010111111111111110001100000001010111110 has to be transmitted as the frame content. If the opening and the closing flags have the form 01111110, which of the following pattern(s) enable(s) data transparency? 01111110101011111111111111000110000000101011111001111110 01111110101011111011111011110001100000001010111110001111110 011111010101011111011111011110001100000001010111110011111010 0111111010101111110111111011000110000000101011111001111110 0111111010101111111111111110001100000100101011111001111110. 10 How many bits are allocated for the host part in a class A type of an IP address? . (a) 8 (b) 16 (c) 24 (d) 32 (e) 48. 11 WHICH OF THE FOLLOWING INDICATE AN ERROR IF AN ODD PARITY APPROACH IS . USED? (A) 10101011 (E) 10011101 (B) 01001010 (C) 10101010 (D) 10010010

12.THERE ARE FIVE (5) TYPES OF CABLING WHICH ARE COMMONLY USED IN A ETHERNET .FOR THE 10BASE5 AND 10BASE2 CABLE STANDARDS, THE MAXIMUM SEGMENT SIZE AND THE MAXIMUM NUMBER OF NODES PER SEGMENT RESPECTIVELY ARE 10BASE5:200M, 30 10BASE2: 500M, 100 10BASE5:100M, 50 10BASE2: 200M, 100 10BASE5:500M, 30 10BASE2: 100M, 30 10BASE5:500M, 100 10BASE2: 200M, 30 10BASE2: 200M, 20 THE ACRONYM ADSL STANDS FOR ANALOG AND DIGITAL SYNCHRONOUS LINK. ASYNCHRONOUS DATA SPECIFIC LANGUAGE ASYMMETRIC DIGITAL SUBSCRIBER LINE APERTURE DISTANCE OF SATELLITE LINK ANALOG DATA SPEED LIMIT. FORTY STATIONS ARE ON AN ETHERNET LAN. A 10-PORT BRIDGE SEGMENTS THE LAN. WHAT IS THE EFFECTIVE AVERAGE DATA RATE OF EACH STATION? (A) 1.0 MBPS (B) 2.0 MBPS (C) 2.5 MBPS (D) 5.0 MBPS (E) 6.0 MBPS.

WHAT BIT IN THE X.25 STANDARD ALLOWS THE USER TO DEFINE THE SOURCE OF . CONTROL INFORMATION? Q (B) D (C) M (D) P (E) R. WHAT IS THE FIELD ON A CELL HEADER IN THE ATM LAYER DETERMINES WHETHER A . CELL CAN BE DROPPED. VPI (B) VCI (C) CLP (D) GFC (E) PT . WHICH OF THE FOLLOWING USES THE GREATEST NUMBER OF LAYERS IN THE OSI . MODEL? (A) BRIDGE (C) ROUTER (B) REPEATER (D) GATEWAY (E) NONE OF THE ABOVE.

WHICH OF THE FOLLOWING LAYER IS ALSO CALLED AS APPLICATION ADAPTATION SIMPLE AND EFFORT ADAPTATION LAYER SIMPLE AND EFFICIENT ADAPTATION LAYER SIMPLE AND EFFICIENT ABNORMAL LAYER SIMPLE AND EFFORT LESS ADAPTATION LAYER SAMPLE AND EFFICIENT ADAPTATION LAYER. A PACKET TRAVELING FROM ONE TOKEN RING NETWORK TO ANOTHER TOKEN RING NETWORK USES WHICH OF THE FOLLOWING SERVICES OF A DEVICE (EACH NETWORK IS AN INDEPENDENT NETWORK) (A) SIMPLE BRIDGE (C) ROUTER BRIDGE (B) REPEATER TRANSPARENT GATEWAY 20 WHAT TYPE OF ADDRESSING DOES THE TRANSPORT LAYER SPECIFICALLY USE? STATION ADDRESSES NETWORK ADDRESSES APPLICATION PROGRAM PORT ADDRESSES DIALOG ADDRESSES INTERFACE ADDRESSES

HTTP (Hyper Text Transfer Protocol) has similarities to both of the following protocols . What is the bit combination used by the SAPI field of ISDN’s data link layer, to control call for . end-to-end signaling in LAPD addressing format? (a) FTP; SMTP (b) FTP; SNMP (c) FTP; MTV (d) FTP; URL (e) SMTP; SNMP (a) 000000 (b) 000010 (c) 010000 (d) 000001 (e) 111111. 23 Which category of AAL of ATM is intended to support connection-oriented data services? . (a) AAL1 (b) AAL2 (c) AAL3 (d) AAL4 (e) AAL5. In the process of congestion control, the bits FECN and BECN of frame relay protocol are . useful to Warn sender and receiver of congestion in the network respectively Warn receiver and sender of congestion in the network respectively Warn only receiver of congestion in the network respectively Warn only sender of congestion in the network respectively Indicate the congestion but no warning to either sender or receiver is given MIME allows what type of data to be sent through SMTP? . (a) Audio (b) Non-ASCII data (c) Image (d) Video (e) All of the above.

Which of the following application protocol is a framework for managing devices in an internet . using the TCP/IP protocol suite. SMTP (b) SNMP (c) FTP (d) TELNET (e) HTTP. Which of the following component of SMTP can transform non-SMTP mail to SMTP format . and vice versa. mail spool (b) mail gateway (c) mail file (d) mail exchanger (e) none of the above. 28 What names objects, defines the type of data that can be stored in an object, and encodes . data for network transmission? (a) MIB (b) SMI BER . 29 Flow Control in data communications (c) SNMP (d) ASN.1 (e) . Can be implemented using a CSMA/CD Protocol Makes a channel an error-free one. Can be implemented using a Stop-and-Wait Protocol Cannot be implemented on a simplex link None of the above.

30 Which of the following is not correct regarding the Simple Mail Transfer Protocol (SMTP) and . Post Office Protocol3 (POP3)? SMTP delivers email by having the source machine establish a TCP connection to port 25 of the destination machine SMTP and POP3 are simple one ASCII protocols POP3 uses the port 20 by default to establish a connection POP3 is used for fetching email from a remote mailbox SMTP provides for mail exchange between users on the same or different computers.

Thanks…