Compromised or misconfigured routers have been a major concern in large-scale networks. Such routers sabotage packet delivery, and thus hurt network performance. Data-plane fault localization (FL) promises to solve this problem. Regrettably, the path-based FL fails to support dynamic routing, and the neighbor-based FL requires a centralized trusted administrative controller (AC) or global clock synchronization in each router and introduces storage overhead for caching packets. To address these problems, we introduce a dynamic distributed and low-cost model, D2FL. Using random two-hop neighborhood authentication, D2FL supports volatile path without the AC or global clock synchronization. Besides, D2FL requires only constant tens of KB for caching which is independent of the packet transmission rate. This is much less than the cache size of DynaFL or DFL which consumes several MB. The simulations show that D2FL achieves low false positive and false negative rate with no more than 3 percent bandwidth overhead. We also implement an open source prototype and evaluate its effect. The result shows that the performance burden in user space is less than 10 percent with the dynamic sampling algorithm.

Datacenter networking has gained increasing popularity in the past few years. While researchers paid considerable efforts to enhance the performance and scalability of datacenter networks, achieving reliable data delivery in these emerging networks with misbehaving routers and switches received far less attention. Unfortunately, documented incidents of router compromise underscore that the capability to identify adversarial routers and switches is an imperative and practical need rather than merely a theoretical exercise. To this end, data-plane fault localization (FL) aims to identify faulty links and is an effective means of achieving high network availability. However, existing secure FL protocols assume that the source node knows the entire outgoing path that delivers the source node's packets and that the path is static and long-lived. These assumptions are invalidated by the dynamic traffic patterns and agile load balancing commonly seen in modern datacenter networks. We propose the first secure FL protocol, DFL, with no requirements on path durability or the source node knowing the outgoing paths. Through a core technique we named delayed function disclosure, DFL incurs little communication overhead and a small, constant router state independent of the network size or the number of flows traversing a router.