1. DATA COMMUNICATION
Lecture-37

2. Recap of Lecture 36
Hamming Code
Data Link Control
Line Discipline

3. Overview of Lecture 35 Line Discipline -ENQ/ACK -POLL/SELECT
Flow Control
Stop-and-Wait
Sliding Window

4. ENQ/ACK When there is a dedicated link between two devices
ENQ/ACK coordinates
Which device may start a transmission?
Whether or not the intended recipient is ready?

5. ENQ/ACK

6. How ENQ/ACK Works

7. Poll/Select Questions in the multi-point systems are Are you ready?
Which of the nodes has the right to use the channel?

8. Poll/Select Polling: When the primary wants to receive data
Selecting: When the primary wants to send data
Every device has an address for identification

9. Poll/Select

10. Select

11. Poll

12. Flow Control
A set of procedures used to restrict the amount of data the sender can send before waiting for acknowledgment
Each receiving device has a buffer

13. Summary Line Discipline -ENQ/ACK -POLL/SELECT Flow Control
Stop-and-Wait
Sliding Window

14. Suggested Reading
Section 10.1,10.2 “Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan