Slow-start Algorithm and Congestion Window

The slow-start algorithm is a congestion control mechanism used in computer networks to manage the flow of data packets. It is part of the Transmission Control Protocol (TCP) and is designed to prevent network congestion by gradually increasing the amount of data sent.

Increasing the Congestion Window Size

The congestion window represents the number of packets that can be sent before the sender needs to wait for an acknowledgment from the receiver. In the slow-start algorithm, the size of the congestion window starts small and gradually increases until it reaches a certain threshold. This process helps to prevent congestion and ensures that the network can handle the increased data flow.

Exponential Increase

The correct answer to the question is option 'A', which states that the size of the congestion window increases exponentially until it reaches a threshold. This means that the congestion window size is doubled with each successful transmission, resulting in a rapid growth rate.

Exponential increase is a fundamental characteristic of the slow-start algorithm. It allows the sender to probe the network to find the optimal transmission rate without overwhelming it with too much traffic at once. By gradually increasing the congestion window size, the algorithm ensures that the network can handle the increased load and avoids congestion.

Threshold

Once the congestion window size reaches a certain threshold, the slow-start algorithm transitions into the congestion avoidance phase. At this point, the congestion window size is increased additively rather than exponentially. This helps to maintain a stable and efficient flow of data without putting excessive strain on the network.

Conclusion

In summary, the slow-start algorithm gradually increases the size of the congestion window to prevent network congestion. The congestion window size starts small and grows exponentially until it reaches a threshold. This exponential increase allows the sender to probe the network and find the optimal transmission rate. Once the threshold is reached, the algorithm transitions into the congestion avoidance phase, where the congestion window size is increased additively. This mechanism helps to maintain a stable and efficient flow of data while preventing congestion in the network.