1. Rivier College CS575: Advanced LANs Chapter 6: Logical Link Control

2. IEEE 802 Protocol Layers Compared to OSI Model
Chapter 6
Logical Link Control

3. Logical Link Control Services
Unacknowledged connectionless service
Connection-mode service
Acknowledged connectionless service
Chapter 6
Logical Link Control

4. Logical Link Control (LLC) Primitives
Chapter 6
Logical Link Control

5. Logical Link Control (LLC) Primitives
Chapter 6
Logical Link Control

6. Three LLC Protocols (referred to as types of operation)
Type 1 operation supports unacknowledged connectionless service
Type 2 operation supports connection-mode service
Type 3 operation supports acknowledged connectionless service
Chapter 6
Logical Link Control

7. LLC Classes available for a single station
Chapter 6
Logical Link Control

8. LLC Protocol Data Unit Formats
Chapter 6
Logical Link Control

9. LLC Protocol Data Units
Chapter 6
Logical Link Control

10. Examples of High-Level Data Link Control (HDLC) Operation
Chapter 6
Logical Link Control

11. Examples of High-Level Data Link Control (HDLC) Operation
Chapter 6
Logical Link Control

12. Service Primitive Types
Chapter 6
Logical Link Control

13. Time Sequence Diagrams for Service Primitives
Chapter 6
Logical Link Control

14. Flow Control: Model of Frame Transmission
Chapter 6
Logical Link Control

15. Stop-and-Wait Flow Control: Link Utilization
Chapter 6
Logical Link Control

16. Sliding-Window Flow Control Process
Chapter 6
Logical Link Control

17. Example of a Sliding-Window Protocol
* Error-detection technique requires an Error-Detecting Code (e.g., CRC)
Chapter 6
Logical Link Control

18. Error Control Mechanisms
Two Types of Possible Errors:
Lost PDU
Damaged PDU (some of the bits have been altered during transmission)
Methods of Error Control:
Error detection (the receiver detects errors and discards PDUs)
Positive acknowledgement is sent confirming error-free PDUs received
Retransmission after timeout
Negative acknowledgement and retransmission
Automatic Repeat Request (ARQ) turns an unreliable data link into a reliable one.
* Error-detection technique requires an Error-Detecting Code (e.g., CRC)
Chapter 6
Logical Link Control

19. Stop-and-Wait Automatic Repeat Request (ARQ)
Chapter 6
Logical Link Control

20. Go-Back-N Automatic Repeat Request (ARQ)
Chapter 6
Logical Link Control