A partial order view of message-passing communication models

TL;DR

This paper presents a unified hierarchy of message-passing communication models for both large-scale and local-scale systems, connecting operational semantics with logical axioms and enabling formal verification techniques.

Contribution

It introduces a unified hierarchy of communication models based on concurrent behaviors, bridging large-scale and local-scale models, and shows they can be axiomatized in monadic second order logic.

Findings

Unified hierarchy encompasses various communication models

All models can be axiomatized in monadic second order logic

Enables bounded verification techniques based on treewidth

Abstract

There is a wide variety of message-passing communication models, ranging from synchronous ''rendez-vous'' communications to fully asynchronous/out-of-order communications. For large-scale distributed systems, the communication model is determined by the transport layer of the network, and a few classes of orders of message delivery (FIFO, causally ordered) have been identified in the early days of distributed computing. For local-scale message-passing applications, e.g., running on a single machine, the communication model may be determined by the actual implementation of message buffers and by how FIFO queues are used. While large-scale communication models, such as causal ordering, are defined by logical axioms, local-scale models are often defined by an operational semantics. In this work, we connect these two approaches, and we present a unified hierarchy of communication models encompassing both large-scale and local-scale models, based on their concurrent behaviors. We also show that all the communication models we consider can be axiomatized in the monadic second order logic, and may therefore benefit from several bounded verification techniques based on bounded special treewidth.