NEST: Network Enforced Session Types (Technical Report)

TL;DR

NEST is a framework that enforces application protocols directly in the network data plane using synthesized packet-level monitors, improving protocol enforcement without modifying application code.

Contribution

It introduces a novel method to generate network-level monitors from session types and implements them in P4 for protocol enforcement.

Findings

NEST can enforce complex protocols in microservice and network-function applications.

The framework handles packet loss and reordering effectively.

Network-level enforcement reduces the need for application-level instrumentation.

Abstract

This paper introduces NEST (Network-Enforced Session Types), a runtime verification framework that moves application-level protocol monitoring into the network fabric. Unlike prior work that instruments or wraps application code, we synthesize packet-level monitors that enforce protocols directly in the data plane. We develop algorithms to generate network-level monitors from session types and extend them to handle packet loss and reordering. We implement NEST in P4 and evaluate it on applications including microservice and network-function models, showing that network-level monitors can enforce realistic non-trivial protocols.