Exponential backoff is a type of algorithm that involves a gradual decrease in the process rate based on responses or results. The drop in rate of the process is done until a suitable level is achieved.
This particular algorithm is used primarily in computer networks in the form of binary exponential backoff, which is used to regulate a specific data block that is being transmitted repeatedly. The algorithm allows for a more even and regular spacing of data retransmission to prevent congestion in network traffic.
An example of using exponential backoff is in the Ethernet protocol. When a host attempts to send a frame of data, the algorithm provides a way for the host to detect any collision or data transmission by another host. Without exponential backoff, there is a risk for both hosts to retransmit the same data over and over again, and result to repeated collisions in an endless cycle. By using exponential backoff, the two hosts may select another value at random within a comfortable range from its originally intended value and assess if a collision will happen.
In Internet terms, exponential backoff is used in retrieving requests based on server request status codes. Developers may use this algorithm in order to prevent overwhelming requests to a server that has been rendered down.