Question Paper: Computer Communication Networks : Question Paper Jun 2013 - Electronics & Communication (Semester 7) | Visveswaraya Technological University (VTU)
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Computer Communication Networks - Jun 2013

Electronics & Communication (Semester 7)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) Explain briefly with relevant examples. The four levels of addresses that are used in an internet employing the TCP/IP protocols.(10 marks) 1 (b) Briefly describe the functions of physical layer and data link layer.(6 marks) 1 (c) Explain the operation of ADSI, using 'Discrete Multione Techniques' indicating the different channels, with a diagram.(4 marks) 2 (a) Explain the mechanism of selective repeat ARQ with diagram showing and window and receive window.(10 marks) 2 (b) With suitable block diagram, explain the stop and wait protocol, for noise less channels. Also write the sender site algorithm.(6 marks) 2 (c) Perform bit stuffing and unstuffing on the given bit stream: 0001111111001111101000. Assume flag as 01111110.(4 marks) 3 (a) Explain how collisions are avoided through, use of IFS contention window and acknowledgements in CSMA/CA. With the help of the flow chart show the procedure for CSMA/CA.(10 marks) 3 (b) Explain 'Token Passing' method of controlled access of the channel.(6 marks) 3 (c) A slotted ALOHA network transmit 200 bit frames using a shared channel with a 200 kbps bandwidth. Find the throughput if the system produces
(i) 1000 frames per second
(ii) 500 frames per second
(iii) 250 frames per second
(4 marks)
4 (a) List the goals of the Ethernet. Explain the features of physical layer in fast Ethernet.(10 marks) 4 (b) Explain two different kinds of services as defined in IEEE 802.11.(6 marks) 4 (c) Write a note on Piconet and Scatternet in Bluetooth.(4 marks) 5 (a) A system with four LANs and five bridges is shown in Fig. Q5(a). Choose B1 as the root bridge. Show the forwarding and blocking ports, after applying the spanning tree procedure.

(10 marks) 5 (b) Define repeater, bridge and router with necessary diagrams.(6 marks) 5 (c) Differentiate between a bus backbone network and star backbone network.(4 marks) 6 (a) An ISP is granted a block of addresses starting with 150.80.0.0/16. The ISP want to distributed these blocks of 2600 customers as follows:
(i) The first group has 2600 medium size business; each needs 16 addresses.
(ii) The second group has 400 small business; each needs 8 addresses.
(iii) The third group has 2000 households; each needs 4 addresses.
Design the sublocks and give the slash notation for each sublock. Find out how many addresses are still available after these allocations.
(10 marks)
6 (b) Explain briefly strategies used to handle the transition from IPv4 to IPv6.(6 marks) 6 (c) A block of addresses is granted to a small organization. One of the addresses is 205.16.37.39/28. What is the first address, last address and number of address in the block.(4 marks) 7 (a) Explain the 'Distance Vector Routing' for the following example shown in Fig.Q7(a).

(10 marks)
7 (b)(i) Briefly discuss the following forwarding techniques: Next-Hop method versus Route method (3 marks) 7 (b)(ii) Briefly discuss the following forwarding techniques: Network-specific method versus Host specific method(3 marks) 7 (c) Distinguish between multicasting and multiple unicating.(4 marks) 8 (a) Explain connection establishment and connection termination in TCP.(10 marks) 8 (b) Write a note on DNS.(6 marks) 8 (c) Write a short note on source port number and destination port number in user datagram.(4 marks)

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