DATA COMMUNICATION Lecture-37
Recap of Lecture 36 Hamming Code Data Link Control Line Discipline
Overview of Lecture 35 Line Discipline -ENQ/ACK -POLL/SELECT Flow Control Stop-and-Wait Sliding Window
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?
ENQ/ACK
How ENQ/ACK Works
Poll/Select Questions in the multi-point systems are Are you ready? Which of the nodes has the right to use the channel?
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
Poll/Select
Select
Poll
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
Summary Line Discipline -ENQ/ACK -POLL/SELECT Flow Control Stop-and-Wait Sliding Window
Suggested Reading Section 10.1,10.2 “Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan