What is cumulative acknowledgement?

In data communications, when a receiver receives a message, it sends an acknowledgement back to the sender to notify it about correct receipt of the message. Cumulative acknowledgement is a process in which the receiver sends a single acknowledgement in response to a finite number of frames received. Through this, the receiver acknowledges that it has correctly received all previous frames or packets. When the sender receives an acknowledgement for frame n, it understands correct delivery of frames n − 1, n − 2 and so on.

Cumulative acknowledgement is used along with sliding window protocols. It reduces the time and bandwidth wasted for sending acknowledgements.

How Cumulative Acknowledgement Works

In cumulative acknowledgement, when the receiver sends ACK n, it means all frames up to and including frame n have been successfully received. This eliminates the need to send individual acknowledgements for each frame, making the communication process more efficient.

Advantages and Disadvantages

Common Use Cases

Cumulative acknowledgement is widely used in transport layer protocols like TCP (Transmission Control Protocol) and data link layer protocols implementing sliding window mechanisms. It is particularly effective in high-speed networks where minimizing control overhead is crucial for performance.

Conclusion

Cumulative acknowledgement optimizes data communication by allowing a single ACK to confirm receipt of multiple frames, reducing network overhead and improving bandwidth efficiency. While it may introduce some delays in error recovery, its benefits make it essential for modern networking protocols.