We continue our series of posts on State Machine Replication (SMR). In this post we discuss the most simple form of SMR: Primary-Backup for crash failures. We will assume synchronous communication. For simplicity, we will consider the case with two replicas, out of which one can crash. Recall that when...| decentralizedthoughts.github.io
In this post we explore adversary failure models that are in between crash and omission: Send Omissions (SO): the adversary can corrupt a party and decide to block any message that the party sends. The corrupted party is not aware that it is corrupted or that the message it wanted...| decentralizedthoughts.github.io
Many systems try to optimize executions that are failure free. If we absolutely knew that there will be no failures, parties could simply send each other messages with our inputs and reach consensus by outputting, say, the majority value. Thus completing the protocol after one round. What happens if there...| decentralizedthoughts.github.io
In the standard distributed computing model, the communication uncertainty is captured by an adversary that can control the message delays. The communication model defines the limits to the power of the adversary to delay messages. There are three basic communication models: the Synchronous model, the Asynchronous model, and the Partial...| decentralizedthoughts.github.io