DipIETE – ET/CS (NEW SCHEME) - Code: DE69 / DC63

Subject: DATA COMMUNICATION & NETWORKS

Time: 3 Hours Max. Marks: 100

NOTE: There are 9 Questions in all.

· Question 1 is compulsory and carries 20 marks. Answer to Q.1 must be written in the space provided for it in the answer book supplied and nowhere else.

· Out of the remaining EIGHT Questions, answer any FIVE Questions. Each question carries 16 marks.

· Any required data not explicitly given, may be suitably assumed and stated.

Q.1 Choose the correct or the best alternative in the following: (210)

a. ________ is the place where telephone companies terminate customer lines and locate switching equipment to interconnect those lines with other networks.

(A) CO (B) ISP

(C) CPE (D) NSP

b. _________ can occur by electrical coupling between nearby twisted pairs.

(A) Impulse Noise (B) Cross-talk

(C) AWGN (D) Intermodulation Noise

c. The digital signal encoding format for ________ is 0 = transition from high to low in middle of internal. 1 = transition from low to high in middle of internal.

(A) Bipolar-AMI (B) Differential Manchester

(C) Manchester (D) BPSK

d. Asymmetric digital subscriber line uses _________ as its line code to send bits on to the channel.

(A) FSK (B) 2BIQ

(C) DMT (D) BPSK

e. The circuit switching has _______

(A) Packet transmission delay (B) Overhead bits in each packet

(C) Call setup delay (D) No-dedicated path

f. MAC in LAN protocol stands for

(A) Max Allowable capacity (B) Medium access control

(C) Min access control (D) More access capacity

g. Bridge operates at _________ of the OSI architecture.

(A) Layer 1 (B) Layer 3

(C) Layer 2 (D) Layer 4

h. ___________ provides a connectionless service for application-level procedures.

(A) TCP (B) RTT

(C) UDP (D) HDLC

i. __________ provides a remote login capability

(A) SMTP (B) TELNET

(C) FTP (D) Ethernet

j. The algorithm used in the IEEE 802.3 standard is

(A) 1- persistent (B) (1 – p) persistent

(C) p - persistent (D) S - persistent

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

Q.2 a. Give differences between

(i) CO and CPE.

(ii) ISP and NSP.

(iii) Indication and Confirmed service primitives. (6)

b. List out the functions of each layer in OSI Model. Illustrate with figure the comparison of OSI and TCP/IP Model. (10)

Q.3 a. Given the spectrum of a channel is between 6 MHz and 4 MHz and . Calculate channel capacity and number of signal levels. (8)

b. Discuss twisted pair w.r.t. the following:

(i) Construction

(ii) Application and

(iii) Frequency characteristics. (8)

Q.4 a. With a neat diagram, explain briefly about noises in Delta Modulation (DM). Also discuss transmission, reception and advantages of DM. (10)

b. Given Message D = 1011001101 (10 bits)

Pattern P = 101101 (6 bits)

Obtain transmitted bit pattern. (6)

Q.5 a. Mention the advantages and disadvantages of Go-back-N-ARQ and selective-reject-ARQ. Explain briefly the working of both the methods. (10)

b. Compare synchronous TDM with statistical TDM. (6)

Q.6 a. With event timing diagram and communication switching techniques compare:

(i) Circuit Switching and (ii) Virtual Circuit Packet Switching (10)

b. Explain Flooding with the help of suitable illustration. (6)

Q.7 a. Discuss the following:

(i) MAC Frame Format (ii) Bridge protocol architecture (10)

b. List out wireless LAN applications. (6)

Q.8 a. Mention the significance of each field with IPv6 Header diagram. (10)

b. How does a IP module in a router fragment a long datagram into two pieces. (6)

Q.9 Write short notes on:

(i) Distance – vector routing. (6)

(ii) UDP. (5)

(iii) SMTP. (5)