Revisiting recommended BGP route flap damping configurations

Clemens, Mosig Bush, Randy Pelsser, Cristel [UCL] Schmidt, Thomas Wählisch, Matthias

BGP Route Flap Damping (RFD) is recommended to suppress BGP churn. Current configuration recommendations for RFD, however, are based on a study from 2010. Since then, BGP churn increased by one order of magnitude, which may lead to outdated RFD parameters and introduce more loss of reachability of stable networks. In this paper, we revisit current recommendations to configure RFD. First, we develop an accurate and scalable emulation of Cisco and Juniper RFD implemen-tations and make it publicly available. Second, we successfully reproduce the 2010 measurement study that justified the current RFD recommendations using current data. Third, we consider the RFD implementation of an additional major router vendor (Juniper), which penalizes BGP churn differently compared to the previously studied Cisco implementation. Fourth, we include IPv6 data from 2020. Our results show that the recommended RFD configuration parameters from 2010, though seemingly rarely used, still hold today in IPv4 and IPv6 and across vendors, even though BGP churn increased significantly. Our study revises metrics to assess the impact of incorrectly configured RFD, discusses collateral damage, and gives insights into sweet spots when damping routes