Common Contracts

Flexible, Cost-Effective Membership Agreement in Synchronous Systems

July 5th, 2006

• Filed
  July 5th, 2006

This paper presents a processor group membership pro- tocol for fault-tolerant distributed real-time systems that utilize periodic, time-triggered scheduling for sending mes- sages over the system’s communication network. The proto- col allows fault-free nodes to reach agreement on the opera- tional state of all nodes in the presence of fail-silent or fail- reporting node failures as well as network failures (lost or corrupted messages). The protocol is based on the principle that each message sent by a node in the membership is ac- knowledged by k other nodes in a system of n nodes, where k can be set to any number between 2 and n 1. Agreement on node failure (membership departure) and agreement on node recovery (membership reintegration) are handled by two different mechanisms. Agreement on departure is guar- anteed if no more than f = k 1 failures occur in the same communication round, while at most one node can be rein- tegrated into the membership per communication round.