当一个包需要重传的时候，会使用 exponential back-off来计算下一次重传的时间。

这个back-off的使用还是相当的广泛：《Adaptive Backoff Synchronization Technique》https://dl.acm.org/doi/pdf/10.1145/74926.74970
The general idea of backoff has been used in one form or another in a number of applications. The approach was first used in Aloha [l], a radio-based, packet-switching network. If a collision occurred in the network, each source would backoff for a random interval before attempting to retransmit. The Ethernet [16] went one step further and used a random retransmission interval in which collision history influenced the choice of the mean of the random intervals. Adaptive control schemes for multiple access communications networks have been analyzed in [13, 12, 141.

第一次使用是在：Aloha [l],
Norman Abramson. The ALOHA System - Another alternative for computer communications. In Proc. Fall Joint Computer Conf., pages 261-285, 1977
https://www.researchgate.net/profile/Norman-Abramson/publication/234790393_THE_ALOHA_SYSTEM_another_alternative_for_computer_communications/links/56b8dfb108ae0a89c12f9184/THE-ALOHA-SYSTEM-another-alternative-for-computer-communications.pdf?origin=publication_detail

这个文章的出处是夏威夷的一个项目，也代表着对长距离通信研究的优势。