JNTU Computer Networks Exam Paper
JNTU III B.Tech II Semester Supplementary Examinations, Aug/Sep 2008
1. (a) Write any four reasons for using layered protocols.
(b) Compare and contrast OSI and TCP/IP models.
2. (a) Compare and contrast SLIP and PPP.
(b) Draw and explain HDLC frame format.
3. (a) Explain the operation of source Routing Bridges.
(b) Measurements of a slotted ALOHA channel with an infinite number of users show that 10 percent of the slots are idle.
i. What is the channel load, G?
ii. What is the throughput?
iii. Is the channel under loaded or overloaded?
4. (a) With an example, explain Hierarchical Routing Algorithm.
(b) With an example, explain multicast Routing Algorithm.
5. (a) Imagine that a two-way handshake rather than a three-way handshake were used to set up connections. In other words, the third message was not required. Are deadlocks now possible? Give an example or show that none exist.
(b) Datagram fragmentation and reassembly are handled by IP and are invisible to TCP. Does this mean that TCP does not have to worry about data arriving in the wrong order?
6. (a) Briefly discuss about the ways network can differ.
(b) Briefly discuss about IP address classes and special IP addresses.
7. (a) Suppose that the TCP congestion window is set to 18K bytes and a timeout occurs. How bit will the window be if the next four transmission bursts are all successful? Assume that the maximum segment size is 1 KB.
(b) If the TCP round-trip time, RTT, is currently 30 msec and the following acknowledgements come in after 26,32, and 24msec, respectively. What is the new RTT estimate? Use ? = 0.9.
(c) Datagram fragmentation and reassembly are handled by IP and are invisible to TCP. Does this mean that TCP does not have to worry about data arriving in the wrong order?
8. (a) Explain in detail methods of DES chaining.
(b) Briefly discuss about IDEA.