How many acknowledgements are needed for stop-and-wait flow control, given that 20 data packets are sent?Correct answer is '20'. Can you explain this answer?

Question

Answer

For stop-and-wait flow control, when n data packets are sent, 'n' acknowledgements are needed. Here, number of packets is 20, so total 20 acknowledgements are required.

Answer

Stop-and-Wait Flow Control

In stop-and-wait flow control, the sender sends a data packet and waits for an acknowledgement (ACK) from the receiver before sending the next packet. This technique ensures that the receiver has successfully received and processed each packet before the sender sends the next one. The sender waits until it receives the ACK or a timeout occurs before retransmitting the packet.

Explanation

In this scenario, 20 data packets are being sent. To ensure reliable communication, each packet must be acknowledged by the receiver.

Process

The process of sending and receiving packets in stop-and-wait flow control is as follows:

The sender sends the first data packet.

The receiver receives the packet, processes it, and sends an ACK back to the sender.

The sender waits to receive the ACK before sending the next packet.

If the sender does not receive the ACK within a certain timeout period, it assumes that the packet was lost or damaged and retransmits the packet.

This process continues until all 20 data packets have been sent and acknowledged.

Acknowledgements

Since each packet needs to be acknowledged individually, all 20 data packets will require an acknowledgement. The sender will send the first packet, wait for the ACK, and then send the second packet, and so on until the twentieth packet is sent and acknowledged.

Conclusion

In stop-and-wait flow control, where each packet is individually acknowledged, all 20 data packets will require an acknowledgement. This ensures reliable communication between the sender and the receiver by confirming the successful receipt and processing of each packet.

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