Synchronous state machine replication for achieving consensus

A computer system comprising:

• one or more processors;
• and
• a memory containing instructions that are executable on the processor of the computer system to carry out a method for committing a block of client requests to a log of committed blocks in a distributed service, the distributed service including N replicas deployed on compute nodes of a computer network, N being a positive integer, the computer system being one of the compute nodes, the method comprising:
• receiving from one of the N replicas a proposal for committing to the log a block of client requests;
• sending a vote on the proposed block to all of the replicas;
• setting a timer to a delay that is twice a maximum transmission delay between any two compute nodes on the computer network and starting the timer;
• and
• after the timer elapses and if there is neither an equivocation during the timer delay nor a stalling condition, committing the proposed block to the log if each replica is a prompt replica, which is a replica that responds to messages on the computer network within the delay of the timer.

A non-transitory computer-readable medium comprising instructions that are executable on a processor of a computer system, wherein the instructions, when executed on the processor, cause the computer system to carry out a method for committing a block of client requests to a log of committed blocks in a distributed service that comprises N replicas deployed on compute nodes of a computer network, N being a positive integer, the method comprising:

• receiving from one of the N replicas a proposal for committing to the log a block of client requests;
• sending a vote on the proposed block to all of the replicas;
• setting a timer to a delay that is twice a maximum transmission delay between any two compute nodes on the computer network and starting the timer;
• and
• after the timer elapses and if there is neither an equivocation during the timer delay nor a stalling condition, committing the proposed block to the log if each replica is a prompt replica, which is a replica that responds to messages on the computer network within the delay of the timer.