Birla Institute of Technology (BIT Mesra) 2007 MS Software Engineering Mid Semester Test - COMPUTER NETWORKS - Distance Learning Programmes ( Software Syste) - Question Paper

Birla Institute of Technology & Science, Pilani

Distance Learning Programmes Division

Second Semester 2006-2007

Mid-Semester Test

(EC-1 Regular)



Course No. : BITS ZC481

Course Title : COMPUTER NETWORKS

Text Box: No. of Pages = one No. of ques. = 5Nature of examination : Closed Book

Weightage : 40%

Duration : two Hours

Date of examination : 03/02/2007 (FN)

Note:

1. Please follow all the Instructions to Candidates provided on the cover page of the ans book.

2. All parts of a ques. should be answered consecutively. every ans should begin from a fresh page.

3. Mobile phones and computers of any type should not be brought inside the exam hall.

4. Use of any unfair means will outcome in severe disciplinary action.



Q.1 (a) For the bit sequence 1101011100 draw the waveform for

i) Binary Encoding

ii) Manchester Encoding

iii) Differential Manchester Encoding



(b) elaborate the advantages of twisting the wires in UTP cables?



(c) What do you mean when we say that a bridge can filter traffic. Why is filtering important? (4 + two + two = 8)



Q.2 (a) The subsequent character encoding is used in a Data Link Protocol:

A: 01000111 B: 11100011 FLAG: 01111110 ESC: 11100000

Show the bit sequence transmitted (in binary) for the five-character frame:

A B ESC ESC FLAG when the framing method used is Flag bytes with byte stuffing.



(b) Consider the delay of pure ALOHA versus slotted ALOHA at low load. Which 1 is less? discuss your ans in brief. (4 + four = 8)



Q.3. For the provided 17-bit sequence, provide the hamming code using odd parity.

1010 1001 1100 1011 one (bit no.1) (8)



Q.4 (a) Ten signals, every requiring 4000Hz, are multiplexed on to a single channel using FDM. How much minimum bandwidth is needed for the multiplexed channel? presume guard bands are 400 Hz wide.



(b) How many frequencies does a full-duplex QAM-64 modem use? (5 + three = 8)



Q.5 (a) For the string provided beneath compute the 8-bit checksum.

110F3F0D0F (Data is represented in Hexadecimal)



(b) Suppose you are designing a selective repeat sliding windows protocol for a 1Mbps point to point link to the moon, which has a 1 way latency of 1.25 seconds. Assuming that every frame carries one Kbytes of data, what is the minimum number of bits you need for the sequence number? (4 + four = 8)





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Earning:   Approval pending.