[Paper] Deciding Serializability in Network Systems

Source: arXiv - 2601.02251v1

Overview

The paper introduces SER, a new modeling language and automated decision procedure that can prove or disprove serializability for concurrent network‑system programs. By translating SER programs into a compact Petri‑net representation, the authors make it possible to reason about an unbounded number of threads and steps—something that was previously only tractable in theory.

Key Contributions

• SER Modeling Language – a restricted yet expressive DSL that captures the essential behavior of concurrent network components while keeping the serializability problem decidable.
• End‑to‑End Decision Procedure – automatically generates either a formal certificate of serializability or a concrete counterexample trace.
• Network‑System Abstraction – a compilation target that maps SER programs to a Petri‑net model, turning serializability checks into reachability queries.
• Scalability Optimizations – novel techniques such as Petri‑net slicing, semilinear‑set compression, and Presburger‑formula manipulation that dramatically shrink the state space.
• Empirical Evaluation – the framework successfully verifies real‑world network software (stateful firewalls, BGP routers, etc.), demonstrating practical viability despite the problem’s theoretical hardness.

Methodology

1. Modeling with SER – Developers describe the concurrent logic of a network component (e.g., packet processing pipelines, routing updates) in SER. The language enforces syntactic restrictions that guarantee decidability without sacrificing the ability to model unbounded threads and loops.
2. Compilation to Petri Nets – The SER program is automatically translated into a colored Petri net where places represent program states and tokens represent thread instances.
3. Serializability as Reachability – Serializability is reduced to a classic Petri‑net reachability question: “Can a state be reached where the concurrent execution diverges from any serial ordering?”
4. Search‑Space Reduction
   • Petri‑net slicing isolates the part of the net relevant to the property under test.
   • Semilinear‑set compression merges equivalent token configurations into compact mathematical representations.
   • Presburger manipulation solves the resulting integer‑linear constraints efficiently.
5. Decision Outcome – If the reachability query is unsatisfiable, SER emits a machine‑checkable proof of serializability. If it is satisfiable, a concrete execution trace that violates serializability is produced for debugging.

Results & Findings

• Correctness Guarantees – The tool proved serializability for all tested firewall and router models, and identified subtle bugs (e.g., race conditions in BGP update handling) that were missed by conventional testing.
• Performance – Even with the worst‑case exponential nature of Petri‑net reachability, the optimizations kept analysis times in the order of seconds to a few minutes for realistic configurations (hundreds of places, thousands of transitions).
• Scalability – The slicing technique reduced the effective net size by up to 90 %, and semilinear compression cut the number of symbolic states by an order of magnitude, enabling analysis of systems that would otherwise be intractable.

Practical Implications

• Network‑Software Verification – Engineers can integrate SER into CI pipelines to automatically certify that new firewall rules or routing protocols preserve serializability, catching concurrency bugs before deployment.
• Debugging Complex Interactions – The generated counterexample traces give developers concrete, step‑by‑step scenarios to reproduce and fix race conditions in distributed control planes.
• Compliance & Safety – For regulated environments (e.g., telecom, finance), having a formal certificate of serializability can satisfy audit requirements and reduce liability.
• Extensible to Other Domains – Although demonstrated on network systems, the SER approach applies to any concurrent service where ordering guarantees matter (e.g., distributed databases, microservice orchestrators).

Limitations & Future Work

• Modeling Restrictions – SER’s decidability hinges on language constraints (e.g., limited forms of dynamic memory allocation), which may require developers to refactor some existing code to fit the model.
• State‑Space Explosion – Extremely large or highly dynamic topologies can still push the underlying Petri‑net reachability solver beyond practical limits, despite the optimizations.
• Tooling Integration – The current prototype is a standalone analyzer; tighter integration with popular network‑configuration languages (e.g., P4, YANG) and CI/CD tools is left for future development.
• Extending Guarantees – The authors plan to broaden the theory to handle weaker consistency models (e.g., eventual consistency) and to explore incremental analysis for continuously evolving network code.

Authors

• Guy Amir
• Mark Barbone
• Nicolas Amat
• Jules Jacobs

Paper Information

• arXiv ID: 2601.02251v1
• Categories: cs.FL, cs.DC, cs.LO, cs.PL
• Published: January 5, 2026
• PDF: Download PDF