Live Long and Prosper – On the Potential of Segment Routing Midpoint Optimization to Improve Network Robustness

Increasing the robustness of networks against failures or traffic changes is an important objective for many operators. Instead of only adapting network configurations to the new conditions in a reactive fashion after a critical event has already occurred, proactively hedging networks against those events has gained increasing popularity over the recent years. A variety of approaches have been proposed that implement this concept of proactive robustness using Segment Routing (SR). However, all of those focus solely on the use of conventional end-to-end SR. In this paper, we show that this can be a limiting factor regarding the achievable level of robustness and that utilizing the Midpoint Optimization concept for SR, instead, facilitates (sometimes considerably) more robust durable Traffic Engineering configurations. Furthermore, it also allows to reduce the number of SR policies required to implement the respective configurations. This is not only discussed from a theoretical perspective but also confirmed by evaluations on real-world data from the backbone network of a Tier-1 Internet Service Provider.