Distributed timestamp method best resilience and latency limits found
On Latency-Optimal Implementations of the Timestamp Object
Distributed, Parallel, and Cluster Computing
Summary
Timestamps help computers working together to keep track of the order of their actions. This paper looks at the best ways to create a system that always gives numbers that go up and never repeat, even when some parts fail or lie. The authors find the limits on how many parts can fail while still working correctly and how fast the system can respond in those conditions. They also introduce a new proof method to show why some speeds or fault tolerance are impossible. This advances understanding of building reliable and fast distributed timestamp systems.
What this means in practice
- •For distributed system engineers: Design timestamp services with proven maximum fault tolerance and minimal message delay under different failure types.
- •For blockchain protocol designers: Implement consensus algorithms using timestamp objects optimized for Byzantine faults with or without signatures.
A theory result. No direct application yet.
Authors
Aurojit Panda, Scott Shenker, Sam Toueg, Wen Zhang
Abstract
Timestamps are widely used in distributed algorithms to order operations. In this paper, we study the timestamp object (TS), which provides a single operation that returns strictly increasing integers. We ask two questions: What is the maximum resilience and the minimum latency of TS implementations in asynchronous message-passing systems, where latency is measured by worst-case message delay? We answer these questions under various types of failure: crash failures, and Byzantine failures with and without digital signatures. To do so, we give lower bounds and algorithms that determine (1) the optimal resilience of TS implementations under each type of failure, and (2) the optimal latency in all cases but one. Along the way, we introduce a new lower-bound proof technique called a cyclic chain argument, which constructs a cycle of indistinguishable schedules along which the returned timestamps must strictly increase, yielding a contradiction.