Crisscross cancellation protocol

摘要

Technologies, systems, and methods for ordered message delivery that avoid message races or crisscrosses between communicating nodes. For example, if Node A sends message 3 towards Node B and, shortly thereafter, Node B sends message X to Node A, Node A would like to know whether or not message X reflects Node B's state after receiving message 3. If Node B received message 3 prior to sending message X, then proper state may be maintained between the nodes. But if messages 3 and X crisscrossed, or if message 3 was never properly received by Node B, then the state between the nodes may be corrupt. Technologies, systems, and methods are provided to avoid such corruption.

主权项

1. A method performed on a computing device that includes at least one processor, memory, and a communications component, the method comprising:
receiving, by the computing device via the communications component, a message that comprises a set of variables configured for use in detecting a message race condition in a communications session between the computing device and a remote computing device, the set of variables including:
a nonce state variable that comprises a value that identifies the communications session according to the computing device,a counter state variable that comprises a value that indicates a last message sent by the computing device to the remote computing device,a remote nonce state variable that comprises a value that identifies the communications session according to the remote computing device as known by the computing device, anda remote counter state variable that comprises a value that indicates a last valid message received by the computing device from the remote computing device.