Binary exponential backoff (BEB) is a decades -old algorithm for coordinating access to a shared channel. In modern networks, BEB plays a crucial role in WiFi and other wireless communication standards. Despite this track record, well-known theoretical results indicate that under bursty traffic, BEB yields poor makespan, and superior algorithms are possible. To date, the degree to which these findings impact performance in wireless networks has not been examined. Here, we investigate a challenging case for BEB: a single burst (batch) of packets that simultaneously contend for access to a wireless channel. Using Network Simulator 3, we incorporate into IEEE 802.11g several newer algorithms that have theoretically-superior makespan guarantees. Surprisingly, we discover that these newer algorithms underperform BEB. Investigating further, we identify as the culprit a common abstraction regarding the cost of collisions. Our experimental results are complemented by analytical arguments that the number of collisions—and not solely makespan—is an important metric to optimize. We propose a new theoretical model that accounts for the cost of collisions, and derive new asymptotic bounds on the makespan for BEB and the newer backoff algorithms that align with our experimental findings. Finally, we argue that these findings have implications for the design of backoff algorithms in wireless networks.

二进制指数退避 (BEB) 是一种已有数十年历史的算法，用于协调对共享信道的访问。在现代网络中，BEB 在 WiFi 和其他无线通信标准中起着至关重要的作用。尽管有这样的记录，众所周知的理论结果表明，在突发流量下，BEB 产生的完工时间很短，并且可以使用卓越的算法。迄今为止，尚未研究这些发现对无线网络性能的影响程度。在这里，我们研究了 BEB 的一个具有挑战性的案例：单个突发（批处理) 同时竞争访问无线信道的数据包。使用网络模拟器 3，我们将几种较新的算法合并到 IEEE 802.11g 中，这些算法具有理论上优越的完工保证。令人惊讶的是，我们发现这些较新的算法表现不如 BEB。进一步调查后，我们将有关冲突成本的常见抽象确定为罪魁祸首。我们的实验结果得到了分析论点的补充，即碰撞次数——而不仅仅是完工时间——是一个重要的优化指标。我们提出了一个新的理论模型，该模型解释了碰撞成本，并为 BEB 和与我们的实验结果一致的较新的退避算法推导出了新的渐近边界。最后，