Class 18: Miscellaneous Data-Link Issues

Held Friday, March 3, 2000

Overview

Today we continue our investigation of the data-link layer by considering what the receiver does when it notices that there's an error in the frame.

Notes

• I was overwhelmed by questions during class preparation time and thefore unable to prepare an outline for today's class. I apologize.
• I will not be grading assignment 3. However, I will check to make sure that you submitted something.
• Reminder: attendance is required!
• Assignment 5 is now available.

Contents

• Sender-Receiver Protocols for the Data-Link Layer
  • Sliding Window

Summary

• Client-server communication at the data-link layer
• Sliding-window protocols

Sender-Receiver Protocols for the Data-Link Layer

• What should the receiver do when it realizes that it has a bad frame?
• Some simple solutions:
  • Require acknowledgements of frames
  • Send a non-acknowledgement for lost frames
• Both solutions require that we somehow name our frames (which adds overhead to the frame)

Sliding Window

• Motivation
• Strategy
• Limitations