A Resilience-Enhancing Approach to Reducing Traffic Downtime Under Consecutive Failures in Backbone Networks

Abstract

Multiprotocol Label Switching (MPLS) plays a critical role in the backbone networks of Internet Service Providers (ISPs), ensuring robust and scalable network operation. By employing label-based switching instead of destination-based IP forwarding, MPLS significantly reduces forwarding complexity and supports advanced traffic engineering mechanisms. Within MPLS, the Label Distribution Protocol (LDP) is typically used for label distribution, relying on routing information from the Interior Gateway Protocol (IGP). When a link or node failure occurs, LDP is forced to wait for the IGP to re-calculate and update the new paths before it can assign labels for Forwarding Equivalence Classes (FECs). This dependency significantly increases service disruption time due to the combined IGP convergence time and the subsequent label replacement mechanism (withdrawing old labels and installing new ones). Therefore, this paper proposes a novel scheme to mitigate LDP’s dependence on the IGP, thereby minimizing network restoration time during network topology changes. The method utilizes an event-driven signaling mechanism to instantly announce link and node outages across the network. Furthermore, it establishes and installs both primary and backup Label Switched Paths (LSPs) during the initial setup phase of the router. Experimental results demonstrate that the proposed method significantly outperforms LDP, achieving a convergence time up to four times faster in large-scale network scenarios and proving superior scalability.