Computer Communication Networks - Dec 2014

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) Discuss the TCP/IP model with functionalities of each layer. Consider source destination and intermediate modes for discussion.(10 marks) 1 (b) Explain the different services provided by telephone networks.(4 marks) 1 (c) Describe four levels of addressing used in internet (TCP/IP) with examples.(6 marks) 2 (a) What is HDLC? Explain different frame formats with control field used by HDLC.(10 marks) 2 (b) A system uses stop-and wait ARQ protocol. If each packet carries 2000bits of data, how long does it take to send 1 million bits of data if the speed is 2×10^{8 m/sec? Ignore transmission, waiting and processing delays. We assume no data or control frame is lost or damaged. Repeat for go-back-n with window size=7}(10 marks) 3 (a) What is channelization in the context of multiple access? What are various channelization techniques? Explain CDMA technique.(10 marks) 3 (b) Two station A and C are connected to a shared channel with data rate 10Mbps. The distance between A and C is 2500m and the propagation speed is 2×10⁸ m/s. Station A starts sending a long frame at time t₁=0; station C starts sending a long frame at time t₂=3μsec. The size of the frame is long enough to guarantee the detection of collision by both stations. Find: (i) The time when station C hears the collision (t₃) (ii) Time when station A hears the collision (t₄); (iii) The number of bits A has sent before detecting the collision; (iv) The number of bits C has sent before detecting the collision.(10 marks) 4 (a) Explain the MAC frame format of IEEE802.3. Write a note on frame length.(10 marks) 4 (b) Explain the features of MAC sublayer and physical layer of Gigabit Ethernet.(10 marks) 5 (a) Briefly explain the three criteria's of a transparent bridge with example.(10 marks) 5 (b) Explain the following connecting devices: (i) Passive hub; (ii) Repeater; (iii) Bridge; (iv) Router; (v) Gateway.(10 marks) 6 (a) What is NAT? Explain how address translation is done in NAT.(9 marks) 6 (b) Why IPv4 to IPv6 transition is required? What are various techniques used in transition? Explain them.(8 marks) 6 (c) Bring out any 3 difference between IPv4 and IPv6 addressing schemes.(3 marks) 7 (a) Explain distance vector routing with an example.(10 marks) 7 (b) With a neat flow chart explain Dijkstra algorithm for the network shown in Fig Q7(b). Assume 'A' as root node. Mention the routing table for root. A refer Fig.Q7(b). (10 marks) 8 (a) How is TCP better than UDP? Explain services offered by TCP.(10 marks) 8 (b) What is Name Space? How is it classified? What is DNS?(10 marks)