Question

Visit the selective repeat protocol Java applet. Suppose both sender window size and receiver window size is 5, the sender need to send six packets to the receiver. If packet #1 is lost and the ack of packet #3 is lost, you may draw a diagram showing how the protocol recover from packet/ack loss and out of order messages.

Answer 1

In the scenario where packet #1 is lost and the ACK for packet #3 is lost while both sender and receiver window sizes are 5, the Selective Repeat protocol ensures that the missing packet and the lost acknowledgment are properly retransmitted and acknowledged. This maintains reliable transmission, allowing the subsequent packets to continue flowing between sender and receiver.

Step-by-step explanation:

The Selective Repeat protocol falls under the category of Automatic Repeat Request (ARQ) protocols, ensuring reliable data transmission over an unreliable service. If the sender window size and the receiver window size are both 5, and the sender needs to send six packets, here's what happens when packet #1 is lost and acknowledgement (ACK) of packet #3 is lost:

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This demonstrates the protocol's ability to handle packet loss and out-of-order message recovery while maintaining a continuous transmission flow.