# Robust Routing Made Easy

## TL;DR

This paper introduces simple, generic blackbox transformations that enhance the robustness of existing routing schemes against independent node failures, maintaining network connectivity with minimal resource overhead.

## Contribution

It presents a novel method to reinforce existing networks against failures using blackbox transformations, simplifying design and verification of robust routing.

## Key findings

- Transforms increase resilience against independent failures
- Minimal additional resources needed for reinforcement
- Effective in real-world network topologies

## Abstract

With the increasing scale of communication networks, the likelihood of failures grows as well. Since these networks form a critical backbone of our digital society, it is important that they rely on robust routing algorithms which ensure connectivity despite such failures. While most modern communication networks feature robust routing mechanisms, these mechanisms are often fairly complex to design and verify, as they need to account for the effects of failures and rerouting on communication. This paper revisits the design of robust routing mechanisms, with the aim to avoid such complexity. In particular, we showcase simple and generic blackbox transformations that increase resilience of routing against independently distributed failures, which allows to simulate the routing scheme on the original network, even in the presence of non-benign node failures (henceforth called faults). This is attractive as the system specification and routing policy can simply be preserved. We present a scheme for constructing such a reinforced network, given an existing (synchronous) network and a routing scheme. We prove that this algorithm comes with small constant overheads, and only requires a minimal amount of additional node and edge resources. At the same time, it allows to tolerate a large number of independent random (node) faults, asymptotically almost surely. We complement our analytical results with simulations on different real-world topologies.