Recipes for faster failure recovery in Smart Grid communication networks

The communication network supporting Smart Grid applications must minimize the time that messages cannot be delivered and thus find alternative paths rapidly. At the same time, the control overhead in normal operation should be limited and not interfere with the data traffic. Hence the routing protocol for such networks has to trade-off these two conflicting goals. One of the candidate routing protocols for Smart Grid networks is the IETF IPv6 routing protocol RPL which was designed for low-power and lossy networks. It strives to consume little bandwidth and energy with its traffic overhead and to be under-reactive to network changes. This design choice was made because in many of the technologies envisioned for such networks the bandwidth is scarce and the link quality may vary. Fluctuations should not trigger unnecessary instabilities, thus the system was designed to have inertia before deciding to modify communication paths. However, this robustness is in direct conflict with the agility that is required for fast recovery in case of communication failures. In this article we investigate the behavior of the local repair failover mechanism, then we propose and evaluate simple options to minimize the recovery time.