Selective Repeat Sliding Window Protocol

Another strategy is to re-send only ones that are actually lost or damaged. The receiver buffers all the frames after that lost one. When the sender finally noticed the problem (e.g. no ack for the lost frame is received within time-out limit), the sender retransmits the frame in question.

Main Window
The main window can be subdivided roughly into four areas:

1. Sender - The representation assumes that the implementation of the Sliding-Window protocol takes place on Stack n. Layer n+1 represents the "data-supplier" for the protocol. It is represented through the text-input-field. One can hand over individual data-packages with "Step" button. So that the animation speed can be adjusted by clicking on it with the right mouse button one can choose the protocol to be simulated.

2. Receiver - It is similar to the sender. The only difference is that the step button here controls the data transfer from the layer n+1 to the layer n. The received Packets is presented in the input text field. By clicking on it with the right mouse button one can choose the protocol to be simulated.

3. Channel - Represent the network channel. By clicking on it with the right mouse button. One can simulate errors.

4. History-Chart - One can adjust the number of messages to be displayed in this area.