Improved Fast Rerouting Using Postprocessing

Abstract

To provide fast traffic recovery upon failures, most modern networks support static Fast Rerouting (FRR) mechanisms for mission critical services. However, configuring FRR mechanisms to tolerate multiple failures poses challenging algorithmic problems. While state-of-the-art solutions leveraging arc-disjoint arborescence-based network decompositions ensure that failover routes always reach their destinations eventually, even under multiple concurrent failures, these routes may be long and introduce unnecessary loads; moreover, they are tailored to worst-case failure scenarios. This paper presents an algorithmic framework for improving a given FRR network decomposition, using postprocessing. In particular, our framework is based on iterative arc swapping strategies and supports a number of use cases, from strengthening the resilience (e.g., in the presence of shared risk link groups) to improving the quality of the resulting routes (e.g., reducing route lengths and induced loads). Our simulations show that postprocessing is indeed beneficial in various scenarios, and can therefore enhance today's approaches.

The New Label Bit Repair Fast Reroute Mechanism

“…In order to minimize the convergence time and improve the stability of the network, techniques such as Fast Reroute (FRR) [1], route backup, and redundant routers are currently used, which try to respond quickly to outages and minimize their negative impact on users and provided services. FRR [2], [3] are technologies and mechanisms that are designed to minimize network recovery time after a network outage through an alternative pre-calculated route, which helps to minimize connection interruptions and reduce negative impacts on the services provided [4]- [6]. Routing protocols and mechanisms: research focuses on improvements to existing routing protocols such as OSPF (Open Shortest Path First) [7], [8], IS-IS (Intermediate System to Intermediate System) [9], or BGP (Border Gateway Protocol) [10]- [12], but also on designing new mechanisms IPFRR (Internet Protocol Fast Reroute) [13], which would ensure effective routing [14]and thus minimize outages [4], [15].…”

“…FRR [2], [3] are technologies and mechanisms that are designed to minimize network recovery time after a network outage through an alternative pre-calculated route, which helps to minimize connection interruptions and reduce negative impacts on the services provided [4]- [6]. Routing protocols and mechanisms: research focuses on improvements to existing routing protocols such as OSPF (Open Shortest Path First) [7], [8], IS-IS (Intermediate System to Intermediate System) [9], or BGP (Border Gateway Protocol) [10]- [12], but also on designing new mechanisms IPFRR (Internet Protocol Fast Reroute) [13], which would ensure effective routing [14]and thus minimize outages [4], [15]. Detection and diagnosis of outages: Research work seeks to improve methods and tools for the detection and diagnosis of network outages, which is important for rapid repair and restoration of connectivity [16]- [18].…”