1. DATA COMMUNICATION
Lecture-41

2. Recap of Lecture 40 Data Link Protocols Asynchronous Protocols

3. Overview of Lecture 41 Synchronous Protocols Bit-Oriented Protocols
HDLC
Link Access Protocols (LAPs)

4. Synchronous Protocols

5. Bit-Oriented Protocols

6. High Level Data Link Control (HDLC)
Bit-oriented data link protocol
Both half-duplex and full-duplex communication
Point-to-point or multipoint links

7. HDLC Systems using HDLC are characterized by their: Station Types
Configurations
Response Modes

8. HDLC-Station Types Station types Primary station: Sends commands
Secondary station: Sends responses
Combined station: One of a set of connected peer devices

9. HDLC-Configurations
Configurations
Unbalanced
Symmetrical
Balanced

11. HDLC-Modes

12. HDLC Frames

13. HDLC Flag Field

14. HDLC Address Field

15. HDLC Control Fields

16. HDLC Control Fields in the Extended Mode

17. Poll/Final Field in HDLC

18. Information Field in HDLC

19. FCS Field in HDLC

20. S-Frames in HDLC

21. U-Frame in HDLC

22. Link Access Procedures
LAPB
Link access procedure, balanced
LAPD
Link access procedure for D- channel
LAPM
Link access procedure for modems

23. Summary Synchronous Protocols Bit-Oriented Protocols HDLC
Link Access Protocols (LAPs)

24. Suggested Reading Section11.4, 11.5
“Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan