The mdt algorithm

TL;DR

This paper introduces the mdt algorithm, a low-complexity method for computing multiple diverse paths in link state routing, enhancing load balancing and rerouting capabilities.

Contribution

The paper presents a novel multipath computation algorithm that efficiently finds at least two diverse paths between node pairs, improving upon traditional Dijkstra-based methods.

Findings

Achieves similar path diversity as multiple Dijkstra runs

Lower computational complexity compared to existing techniques

Effective for real and synthetic network topologies

Abstract

Link state routing protocols such as OSPF or IS-IS currently use only best paths to forward IP packets throughout a domain. The optimality of sub-paths ensures consistency of hop by hop forwarding although paths, calculated using Dijkstra algorithm, are recursively composed. According to the link metric, the diversity of existing paths can be underestimated using only best paths. Hence, it reduces potential benefits of multipath applications such as load balancing and fast rerouting. In this paper, we propose a low time complexity multipath computation algorithm able to calculate at least two paths with a different first hop between all pairs of nodes in the network if such next hops exist. Using real and generated topologies, we evaluate and compare the complexity of our proposition with several techniques. Simulation results suggest that the path diversity achieved with our proposition is approximatively the same that the one obtained using consecutive Dijsktra computations, but with a lower time complexity.