Microloop prevention by introducting a local convergence delay

Abstract

This document describes a mechanism for link-state routing protocols to prevent local transient forwarding loops in case of link failure. This mechanism Proposes a two-steps convergence by introducing a delay between the convergence of the node adjacent to the topology change and the network wide convergence. As this mechanism delays the IGP convergence it may only be used for planned maintenance or when fast reroute protects the traffic between the link failure and the IGP convergence. Simulations using real network topologies have been performed and show that local loops are a significant portion (>50%) of the total forwarding loops.