Partially synchronous Byzantine consensus protocols typically structure their execution into a sequence of views, each with a designated leader process. The key to guaranteeing liveness in these protocols is to ensure that all correct processes eventually overlap in a view with a correct leader for long enough to reach a decision. We propose a simple view synchronizer abstraction that encapsulates the corresponding functionality for Byzantine consensus protocols, thus simplifying their design. We present a formal specification of a view synchronizer and its implementation under partial synchrony, which runs in bounded space despite tolerating message loss during asynchronous periods. We show that our synchronizer specification is strong enough to guarantee liveness for single-shot versions of several well-known Byzantine consensus protocols, including PBFT and HotStuff. We furthermore give precise latency bounds for these protocols when using our synchronizer. By factoring out the functionality of view synchronization we are able to specify and analyze the protocols in a uniform framework, which allows comparing them and highlights trade-offs.

部分同步的拜占庭共识协议通常将它们的执行构造成一系列视图，每个视图都有一个指定的领导进程。在这些协议中保证活跃性的关键是确保所有正确的进程最终在视图中与正确的领导者重叠足够长的时间以做出决定。我们提出了一个简单的视图同步器抽象，封装了拜占庭共识协议的相应功能，从而简化了它们的设计。我们提出了视图同步器的正式规范及其在部分同步下的实现，尽管在异步期间容忍消息丢失，但它在有界空间中运行。我们展示了我们的同步器规范足够强大，可以保证几个著名的拜占庭共识协议的单次版本的活跃性，包括 PBFT 和 HotStuff。在使用我们的同步器时，我们还为这些协议提供了精确的延迟范围。通过分解视图同步的功能，我们能够在一个统一的框架中指定和分析协议，这允许比较它们并突出权衡。