Saturday, November 5, 2011
Tuesday, March 9, 2010
COMPUTER NETWORKS May/Jun 2007
Fifth semester
Computer Science and Engineering
CS1302 -COMPUTER NETWORKS
(Regulation 2004)
| 1. State the purpose of layering in networks? 2. At which level of OSI model does repeaters, bridges, routers and gateways operate? 3. State the difference between token ring and FDDI? 4. Give the structure of encoder and decoder in error correction. 5. What is meant by IP spoofing? How can be router be used to prevent IP spoofing? 6. What kind of routing information do routers exchange among themselves while running distance vector algorithm? In particular, briefly describe the format of the routing information that is exchanged. 7. Briefly describe two advantages of using packet switching for data transmission. 8. Explain how TCP flow control works. 9. Why is DNS necessary? State it significance. 10. What is Security Parameter Index? PART B (5 x 16 = 80) 11 (a) (i). List four properties by which transmission media can differ. (4) (a) (ii). Three packets – switching networks each contain n nodes. The networks has a star topology has a star topology with a central switch, a ring respectively and a third is fully interconnected with a wire form every node to every other node. What are the best, average and worst case transmission paths in hops? (12) (or) (b) (ii). Explain in detail the data transmission in OSI reference model. (8)11.(b) (i). Describe the key elements of protocols and the standards. (8) 12. (a) (i) How does the 802.11 media access control protocol ensure that the receiver has a greater chance to transmit the acknowledgement frame before any other wireless stations grab the media? Does it always guarantee that the acknowledgement frame sent by the receiver will not collide with another frame transmitted by another wireless station? (8) (a) (ii) Describe the collision avoidance mechanism used in 802.11 wireless LAN. In particular, how such a mechanism solves the hidden terminal problem. (8) 13(a) (i). How is the looping problem solved by switches and by routers? How do switches and by routers. How do switches/routers handle link failure? (8) (or) 12. (b) Describe two approaches by which packet loss is detected in a Go back –N ARQ protocol and Selective Repeat. 13. (a) (ii). Explain the IP addressing. (8) 13. (b)(ii). In the virtual circuit network service model, before a virtual circuit is setup, the source router needs to specify a path (e.g., the shortest path) from the source to the destination. What additional information do we need to maintain in the routing table to support this function? Write down the resulting routing table. (8)(or) 13. (b) (i). Compare and Contrast Link State and Distance Vector algorithms. (8) 14. a) If UDP does not provide any service guarantees or reliable transfer, why can’t application directly access IP and do without it? Explain UDP in details. (16) (or) 14. (b) What is QoS in internetworking? State the technique to improve QoS. (16). 15. (a) What are the following acronym SMTP, FTP, WWW and HTTP stand for? Explain their uses and state the strengths and weaknesses of each of them.(16) 15. (b) (i). Explain in role of a DNS on a computer network, including its involvement in the process of a user accessing a web page. (8) |
COMPUTER NETWORKS Nov/Dec 2006
Fifth semester
Computer Science and Engineering
CS1302 -COMPUTER NETWORKS
2. A sine wave has a frequency of 6Hz. What is its period?
3. Briefly discuss stop-and-wait method of flow control.
4. List the two types of data frames in FDDI.
5. List the two forms in which virtual circuit packet switching is implemented.
6. Which class does the following IP address belong to?
7. What is a datagram socket?
8. “TCP software is implemented as a Finite State Machine”, Discuss.
9. What is a Domain Name Server?
10. State the application layer protocol in the TCP/IP protocol suite that provides access to a networked file server.
(ii) With relevant examples differentiate between simplex, half duplex and full duplex communication.
(iii) A Sine wave completes one cycle in 25 μs. What is its frequency? Express the frequency in KHz.
(or)
(iii) A network has ‘n’ devices. Determine the number of cable links required for a mesh, ring, bus and star topology.
12. (a) (i) A block of 32 bits has to be transmitted. Discuss how the thirty two bit block is transmitted to the receiver using Longitudinal Redundancy Check.
(ii) Consider a 32 bit block of data 11100111 11011101 00111001 10101001 that has to be transmitted. If Longitudinal Redundancy Check is used what is the transmitted bit stream?
(iii) In the Hamming code, for a data unit of m bits how do you compute the number of redundant bits ‘r’ needed?
12. (b) (i) List the three main functions performed by the data link layer of the ISO OSI model.
(iii) How does a Token Ring LAN operate? Discuss.
(iv) List and briefly discuss the two different basic transmission technologies that can be used to set up wireless LAN’s.
13. (a) (i) State which layers of the ISO OSI model does the following interconnecting devices operate.
(or)
13. (b) (i) What is subnetting? Discuss. Also state which classes of IP address can be subnetted.
(iii) How can we prove that we have 2, 147, 48, 648 address in class A?
(iv) What is the subnetwork address if the destination address is 200.45.34.56 and the subnet mask is 255.255.240.0?
14. (a) (i) List and discuss the various primitives for a simple transport service.
(ii) “DNS can use the services of UDP or TCP using port 53”. Discuss when UDP is used and when TCP is used.
14. (b) (i) Discuss connection establishment and connection release in TCP.
(iii) Discuss the strategies TCP uses to avoid congestion.
15. (a) (i) With a relevant example discuss how the domain space is divided.
(or)
15. (b) (i) Discuss how Simple Mail Transfer Protocol (SMTP) works? Can multimedia messages be transmitted using SMTP? Discuss.
Friday, July 4, 2008
COMPUTER NETWORKS 2006 - B.E CSE
CS339 - COMPUTER NETWORKS
Time: Three Hours Maximum: 100 Marks
Answer All The Questions
PART – A (10 x 2 = 20 Marks)
1. Why network software is organized as a series of layer?
2. What are the two kinds of light sources used in fiber cables?
3. Reliability of CRC is better than that of simple parity and LRC. Justify this statement.
4. What is meant by bit stuffing?
5. Write short notes on virtual circuit organization of the subnet.
6. Differentiate between adaptive and non-adaptive routing algorithms.
7. What is meant by upward and downward multiplexing.
8. Mention some applications where UDP is preferred over TCP?
9. Mention the layer in which email gateway function. Also mention some of its applications
10. Define encryption
PART – B (5 x 16 = 80 Marks)
11.i) Compare OSI and TCP / IP reference models on form of their merits and demerits. (10)
ii) Differentiate between broadcast networks and point to point networks. (6)
12.a)i) Explain the CSMA/CD protocol with binary exponential back off algorithm used internet. (10)
ii) Assume that a network can cover a distance of 5000 meters and the RTT is 100 µ sec of the network operates at a speed of 20Mbps. What should be the minimum frame size to employ CSMA / CD? (6)
(OR)
12.b)i) Explain the sliding window protocol and compare its performance against the simple stop and wait protocol. (10)
ii) Given message is M(X) = X5 + X4+ X + 1 and the generator is G(X) = X4+X3+1 Compute CRC. (6)
13.a)i) Explain the distance vector routing algorithm. (8)
ii) Find the shortest path from node A to node D in the following network using the Bell mark kord routing algorithm. (8)
(OR)
13.b)i) Given three IP addresses are 32.46.7.3, 200.132.110.35 and 140.75.8.92. Find their classes, network addresses, broadcast address and their subnet marks. (6)
ii) Explain the token breket algorithm and compare its performance against the leaky bueket algorithm (10)
14.a)i) Explain the Bres-way handshak protocol used to establish the connection in the transport layer. Also explain the protocol used to release the connection. (8)
ii) Explain the transport service access point and the various schemers used by the transport layer to find the TSAP at a server. (8)
(OR)
14.b)i) Explain the various fields of TCP header. (8)
ii) Write short notes about the pseudo header included in the TCP checkroom. (4)
iii) Draw the UDP header and explain its fields (4)
15.a) Explain the DNS in terms of name space, resource record and name server. (16)
(OR)
15.b) Explain the architecture of WWW as on client / server application (16)
