Rajiv Gandhi Proudyogiki Vishwavidyalaya 2011 B.E Information Technology It503(computer networks)__ - Question Paper

IT-503

B. E. (Fifth Semester) EXAMINATION, Dec, 2011

(Information Technology Engg. Branch)

COMPUTER NETWORKS

(IT-503)

Time : Three Hours

Maximum Marks : 100

Minimum Pass Marks : 35

Note: Attempt one question from each Unit. All questions carry equal marks.

Unit-I

1. (a) What is the diference between connection oriented communication and connectionless communication? Explain the types of service. What are service

primitives ? 10

(b) What are the advantages and disadvantages of having international standards for network protocols ? 10

Or

2. (a) What is the difference between confirmed service and unconfirmed service ? For each of the following, tell whether it might be a confirmed service and unconfirmed service both or neither : 10

(i) Data transmission

(ii) Connection release

(iii) Connection establishment

(b) Explain the following : 10

(i) Virtual terminal protocol

(ii) Negotiation in discussing network protocol

Unit-II

3. (a) Explain the framing methods in data link layer. Which one of these uses code violations to mark frame boundaries ? 10

(b) A channel has a bit rate of 4 kbps and propagation delay of 20 m sec. For what range of frame sizes does stop and wait give an efficiency of at least 50% ? 10

Or

4. (a) If the bit string 0111101111101111110 is subjected to bit stuffing, what is the output of string ? 5

(b) For P = 110011 and M = 11100011, find the CRC. 5

(c) Consider the use of 1000 bit frames on a 1 Mbps satellite channel with 270 ms delay. What is the maximum link utilization for : 10

(i) Stop and wait flow control.

(ii) Continuous flow control with window size 7.

(iii) Continuous flow control with window size 1277.

Unit-III

5. (a) Compare the capacity allocation schemes for IEEE 8025 token ring and FDDI. What are the relative pros and cons ? 10

(b) Explain persistent and non-persistent CSMA. 10

Or

6. (a) Explain CSMA/CD protocol. Also discuss about collision free protocols. 10

(b) For a token ring, LAN, suppose that the destination station removes the data frame and immediately sends a short acknowledgement frame to the sender, rather than letting the original frame return to sender. How will this affect performance ? 10

Unit-IV

7. (a) Explain the two classes of routing algorithms : 10

(i) Adaptive algorithms

(ii) Non-adaptive algorithms

Discuss about multipath routing.

(b) Explain OSI connection oriented network service primitives. 10

Or

8. (a) Compare virtual circuit and datagram with in a subnet. 10

(b) What is the difference, if any, between static routing using two equally weighted alternatives and selective flooding using only the two best paths ? Justify your answer. 10

Unit-V

9. (a) Explain the issue of addressing, multiplexing and flow control in connection oriented transport protocol mechanisms. 10

(b) Why is UDP needed ? Why can't user program directly access IP? 10

Or

10. (a) Compare TCP and OSI Class 4 transport protocol. 10

(b) Write notes on the configuration of the following Networking devices : 10

(i) Switches

(ii) Bridges

(iii) Hubs

(iv) Gateway

IT-503

B. E. (Fifth Semester) EXAMINATION, Dec, 2011

(Information Technology Engg. Branch)

COMPUTER NETWORKS

(IT-503)

Time : Three Hours

Maximum Marks : 100

Minimum Pass Marks : 35

Note: Attempt one question from each Unit. All questions carry equal marks.

Unit-I

1. (a) What is the diference between connection oriented communication and connectionless communication? Explain the types of service. What are service

primitives ? 10

(b) What are the advantages and disadvantages of having international standards for network protocols ? 10

Or

2. (a) What is the difference between confirmed service and unconfirmed service ? For each of the following, tell whether it might be a confirmed service and unconfirmed service both or neither : 10

(i) Data transmission

(ii) Connection release

(iii) Connection establishment

(b) Explain the following : 10

(i) Virtual terminal protocol

(ii) Negotiation in discussing network protocol

Unit-II

3. (a) Explain the framing methods in data link layer. Which one of these uses code violations to mark frame boundaries ? 10

(b) A channel has a bit rate of 4 kbps and propagation delay of 20 m sec. For what range of frame sizes does stop and wait give an efficiency of at least 50% ? 10

Or

4. (a) If the bit string 0111101111101111110 is subjected to bit stuffing, what is the output of string ? 5

(b) For P = 110011 and M = 11100011, find the CRC. 5

(c) Consider the use of 1000 bit frames on a 1 Mbps satellite channel with 270 ms delay. What is the maximum link utilization for : 10

(i) Stop and wait flow control.

(ii) Continuous flow control with window size 7.

(iii) Continuous flow control with window size 1277.

Unit-III

5. (a) Compare the capacity allocation schemes for IEEE 8025 token ring and FDDI. What are the relative pros and cons ? 10

(b) Explain persistent and non-persistent CSMA. 10

Or

6. (a) Explain CSMA/CD protocol. Also discuss about collision free protocols. 10

(b) For a token ring, LAN, suppose that the destination station removes the data frame and immediately sends a short acknowledgement frame to the sender, rather than letting the original frame return to sender. How will this affect performance ? 10

Unit-IV

7. (a) Explain the two classes of routing algorithms : 10

(i) Adaptive algorithms

(ii) Non-adaptive algorithms

Discuss about multipath routing.

(b) Explain OSI connection oriented network service primitives. 10

Or

8. (a) Compare virtual circuit and datagram with in a subnet. 10

(b) What is the difference, if any, between static routing using two equally

weighted alternatives and selective flooding using only the two best paths ?

Justify your answer. 10

Unit-V

9. (a) Explain the issue of addressing, multiplexing and flow control in connection

oriented transport protocol mechanisms. 10

(b) Why is UDP needed ? Why can't user program directly access IP? 10

Or

10. (a) Compare TCP and OSI Class 4 transport protocol. 10

(b) Write notes on the configuration of the following Networking devices : 10

(i) Switches

(ii) Bridges

(iii) Hubs

(iv) Gateway