Robustly disjoint paths with segment routing

Motivated by conversations with operators and by possibilities to unlock future Internet-based applications, we study how to enable Internet Service Providers (ISPs) to reliably offer connectivity through disjoint paths as an advanced, value-added service. As ISPs are increasingly deploying Segment Routing (SR), we focus on implementing such service with SR. We introduce the concept of robustly disjoint paths , pairs of paths that are constructed to remain disjoint even after an input set of failures, with no external intervention (e.g., configuration change). We extend the routing theory, study the problem complexity, and design efficient algorithms to automatically compute SR-based robustly disjoint paths. Our algorithms enable a fully automated approach to offer the disjoint-path connectivity, based on configuration synthesis. Our evaluation on real topologies shows that such an approach is practical, and scales to large ISP networks.