ChainSync: A Synchronization Protocol for Strict Sequential Execution in Linear Distributed Pipelines

ChainSync is a lightweight application-layer protocol that runs over reliable TCP connections to synchronize a fixed linear chain of distributed processes such that they execute their local tasks in strict sequential order and only after every process in the chain has confirmed it is ready. The protocol has four phases: 1) a forward "readiness" wave, 2) a backward "start" wave, 3) a forward "execution" wave, and 4) a backward exit wave. The design guarantees strict ordering even when nodes become ready at very different times and requires only point-to-point TCP connections along the chain, thus no central coordinator is needed.