JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA COMPUTER NETWORKS Previous Question Paper (June/July - 2018 - R13)
Part A is compulsory which carries 20 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit.
Part A
Give a critical comparison between OSI and TCP-IP network models.
Answer
The OSI model is a theoretical, seven-layer reference model that strictly separates services, interfaces, and protocols, whereas the TCP/IP model is a practical, four-layer implementation-based model. OSI provides a clearer distinction between layers but is often considered more complex and less efficient. TCP/IP combines the session, presentation, and application layers of OSI into a single application layer, and the physical and data link layers into a network access layer, making it more flexible and widely adopted in real-world internetworking.
Compare working of ALOHA and Slotted ALOHA. How is the performance improved in Slotted ALOHA?
Answer
In pure ALOHA, stations transmit frames at any time, leading to frequent collisions. Slotted ALOHA improves performance by dividing time into discrete slots; stations are only permitted to transmit at the beginning of a slot. This synchronization reduces the vulnerability period of a frame from 2T to T, effectively doubling the maximum channel utilization from 18.4% in pure ALOHA to 36.8% in Slotted ALOHA.
What is count-to-infinity problem in Distance Vector Routing? Give a solution to solve this problem.
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Explain the process of fragmentation with suitable examples.
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Explain the slow start algorithm used in TCP congestion control.
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Part B
A bit stream 10011101 is transmitted using the standard CRC method. The generator polynomial is x3 + 1. Show the actual bit string transmitted. Suppose that the third bit from the left is inverted during transmission. Show that this error is detected at the receiver’s end. Give an example of bit errors in the bit string transmitted that will not be detected by the receiver.
Answer
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In CRC, show the relationship between the size of the divisor and the remainder.
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Explain about Go-Back N and Selective Repeat versions of sliding window.
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Give the frame format of standard IEEE 802.3 Ethernet and explain the binary exponential backoff algorithm used in Ethernet.
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Store-and-forward switches have an advantage over cut-through switches with respect to damaged frames. Explain.
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Explain the working of Token Passing as a Collision Free Protocol.
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For hierarchical routing with 4800 routers, what region and cluster sizes should be chosen to minimize the size of the routing table for a three-layer hierarchy?
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Explain Hierarchical Routing.
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What are the advantages of Token Bucket over Leaky Bucket? Explain the working of Token Bucket algorithm with suitable diagrams.
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Write Short notes on:
a) Tunneling
b) IPv4 Header Format.
Tunneling
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IPv4 Header Format.
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A network on the Internet has a subnet mask of 255.255.240.0. What is the maximum number of hosts it can handle?
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Why do we need addressing at transport layer also? With a neat diagram explain how a process in one host establishes a connection with a server in another host.
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With a neat diagram explain the different fields of TCP Segment header.
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Give a brief introduction to Electronic Mail and FTP applications.
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