Efficiency of Routing and Resilience Mechanisms in Packet-Switched Networks

This paper compares the efficiency of different routing and resilience mechanisms to avoid congestion in a network for a set of protected failures. A routing mechanism is more efficient than another one if it achieves a lower maximum link utilization in the same networking scenario. With resilience requirements, the maximum link utilization over the set of protected failure scenarios becomes the critical value. We consider standard and optimized configurations of single shortest path (SSP) and equal-cost multipath (ECMP) routing as well as several types of end-to-end (e2e) path protection and MPLS fast reroute (FRR). We investigate how well these resilience mechanisms can cope with different network structures and with different sets of protected failures. The results show that routing optimization reduces the maximum link utilization significantly both with and without protection of failures. The optimization potential for resilient routing is limited by the applied mechanism and heavily depends on the network structure and the set of protected failure scenarios.