This applet animates the Go-Back-N protocol, covered in Section 3.4 of Computer Networking: A Top-Down Approach by James F. Kurose & Keith W. Ross.
In this applet, the sending window limits the sender to a maximum of five outstanding, unacknowledged packets.
To send a new packet, click on the "Send New" button below. This will create a packet and begin the simulation of data moving between sender and receiver.
To simulate the loss of a packet or acknowledgment, click on it and then press the "Kill Packet/Ack" button. Use the "Stop Animation" button to make selecting the packet easier. Press the "Resume" button to continue the simulation.
You may speed up or slow down the simulation by using the "Faster" or "Slower" buttons respectively.
** NOTE: To properly run this applet, J2SE 1.4.2 needs to be installed on your machine (If you do not have Java installed it can be downloaded from Here)
Updated by Matt Shatley and Chris Hoffman for
Professor Paul Amer (amer At udel.edu) University of Delaware (2008).
Original applet was coded by Shamiul Azom for Professor Martin Reisslein, Arizona State University (2001).