Computer Network - Dec 2014

Computer Engineering (Semester 5)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Why there is a need for layered designing for networking and communication? Compare the TCP/IP and OSI reference models.(10 marks) 1 (b) Explain the modes of propagating light along optical channels. What are the advantages over other guided media?(10 marks) 2 (a) Explain the need for DNS and describe the protocol functioning.(10 marks) 2 (b) Explain the different elements of transport protocols.(10 marks) 3 (a) Explain how TCP handles error control and flow control.(10 marks) 3 (b) Why is flow control needed? What are the mechanisms? Explain how the Go-Back-N and Selective Repeat ARQ differ from each other.(10 marks) 4 (a) Why there is a need for congestion control? What are the different mechanisms? Explain them.(10 marks) 4 (b) Explain CSMA Protocols. Explain how collisions are handled in CSMA/CD,(10 marks) 5 (a) Why there is need for farming?
The following 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 four character frame: A B ESC FLAG
when each of the following framing methods are used:
a) Character count
b) Flag byte and byte stuffing
c) Starting and Ending flag bytes, with bit stuffing.(10 marks) 5 (b) Compare the network layer protocols Ipv4 and Ipv6.(10 marks)

Give Short notes on any four:

6 (a) SNMP(5 marks) 6 (b) HTTP(5 marks) 6 (c) BGP(5 marks) 6 (d) Ethernet(5 marks) 6 (e) Virtual LAN(5 marks)