JNTU III B.Tech II Semester
Supplimentary Examinations, Aug/Sep 2008
1. (a) List two advantages and two disadvantages of having international standards for network, Protocols?
(b) Write short notes on interfaces and services of ISO layers.
2. (a) The following data fragment occurs in the middle of a data stream for which the character-stuffing algorithm described in the text is used: DLE, STX, A, DLE, B, DLE, ETX. What is the output after stuffing?
(b) When bit stuffing is used, is it possible for the loss, insertion, or modification of a single bit to cause an error not detected by the checksum? If not, why not? If so, how? Does the checksum length play a role here?
(c) Data link protocols almost always put the CRC in a trailer, rather than in a header. Why?
3. (a) What is collision free protocols? Explain Binary count down protocol.
(b) Explain in detail, Adaptive free walk protocol.
4. What is congestion? How does it differ from flow control? Discuss about the general principles of congestion? Briefly discuss about policies that affect congestion.
5. (a) Briefly explain the concepts of Flow Control and Buffering.
(b) 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.
6. (a) Briefly discuss ICMP.
(b) With an example, explain Address resolution protocol.
7. (a) Draw and explain in detail the TCP Header.
(b) Briefly discuss TCP connection Management.
8. (a) PGP does not support canonicalization as does PEM. Why not?
(b) Assuming that everyone on the Internet used PGP, could a PGP message be sent to an arbitrary Internet address and be decoded correctly by all concerned? Discuss your answer.