Page 139 - DCAP207_NETWORKS_DCAP406_COMPUTER_NETWORKS

Computer Networks/Networks

Notes 7. How are frames created and checksums applied on them?
8. How does the data link layer handle errors and lost frames due to some hardware problem?
9. Why is Hamming code considered important among various error detection and recovery
techniques?
10. What procedure is used to prevent a stream of binary data from being misinterpreted as a
HDLC flag?

11. Explain any three techniques by which frame boundaries may be encoded within a
transmitted bit stream. Describe character stuffing and state which technique it is associated
with and why it is needed.
12. How does pipelining improve data link layer protocol throughput?
13. The IEEE has split the data link layer in LANs such as Ethernet and Token ring into two sub
layers. Which of these layers deals with error detection?
14. How does PPP transmit datagrams over serial point-to-point links?
15. How does PPP establish link for authenticated transfer of file?
16. What are different methods of authentication adopted in PPP technique?

17. How can a collision be avoided in CSMA/CD network?
18. Compare and contrast CSMA/CD and token passing access methods.
19. Is Slotted Aloha always better than Aloha? Explain your answer with justification.
20. What are the basic components, which constitutes an Ethernet?

21. On what basis is Ethernet versions defined? List them.
22. What are the different frequencies and data rates available for wireless LAN?
23. What are the technologies available for Wireless LAN?

Answers: Self Assessment

1. Data link layer 2. Unacknowledged connectionless service

3. Framing 4. Rate of data transmission
5. nil 6. a sequence number
7. one outstanding frame 8. False
9. True 10. True
11. False

8.13 Further Readings

Books Andrew S. Tanenbaum, Computer Networks, Prentice Hall.
Behrouz A. Forouzan and Sophia Chung Fegan, Data Communications and
Networking, McGraw-Hill Companies.

J. D. Spragins, Telecommunications Protocols and Design, Addison-Wesley.

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