2. University of Education Flow and Error Control Flow Control Error Control

3. University of Education Flow control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment. Note :

5. Model of Frame Transmission University of Education

9. Sliding Window University of Education

10. Example Sliding Window University of Education

12. University of Education Error control in the data link layer is based on automatic repeat request, which is the retransmission of data. Error Control Note :

17. Stop and Wait -Diagram University of Education

18. University of Education Stop and Wait ARQ Normal Operation

19. University of Education Stop-and-Wait ARQ, lost frame

20. University of Education Stop-and-Wait ARQ, lost ACK frame

21. University of Education In Stop-and-Wait ARQ, numbering frames prevents the retaining of duplicate frames. Note :

22. University of Education Numbered acknowledgments are needed if an acknowledgment is delayed and the next frame is lost. Note :

23. University of Education Piggybacking

24. University of Education Go-Back-N ARQ Sequence Number Sender and Receiver Sliding Window Control Variables and Timers Acknowledgment Resending Frames Operation

29. University of Education Sender sliding window

30. University of Education Receiver sliding window

31. University of Education Go-Back-N ARQ, normal operation

32. University of Education Go-Back-N ARQ, lost frame

33. University of Education Go-Back-N ARQ: sender window size

34. University of Education In Go-Back-N ARQ, the size of the sender window must be less than 2m; the size of the receiver window is always 1. Note :

36. Figure 11.7 University of Education