One More Weight is Enough: Toward the Optimal Traffic Engineering with OSPF

TL;DR

This paper introduces SPEF, a new OSPF-based routing protocol that optimally balances traffic by adding a single weight per link, improving network performance through a theoretically grounded and practically implementable approach.

Contribution

It proposes a novel generic objective function for traffic engineering, demonstrates the conversion of optimal routes to shortest paths with positive link weights, and develops SPEF, an efficient distributed protocol for optimal traffic splitting.

Findings

SPEF achieves better link utilization than OSPF.

SPEF provably attains optimal traffic engineering.

Numerical results confirm improved load distribution.

Abstract

Traffic Engineering (TE) leverages information of network traffic to generate a routing scheme optimizing the traffic distribution so as to advance network performance. However, optimize the link weights for OSPF to the offered traffic is an known NP-hard problem. In this paper, motivated by the fairness concept of congestion control, we firstly propose a new generic objective function, where various interests of providers can be extracted with different parameter settings. And then, we model the optimal TE as the utility maximization of multi-commodity flows with the generic objective function and theoretically show that any given set of optimal routes corresponding to a particular objective function can be converted to shortest paths with respect to a set of positive link weights. This can be directly configured on OSPF-based protocols. On these bases, we employ the Network Entropy Maximization(NEM) framework and develop a new OSPF-based routing protocol, SPEF, to realize a flexible way to split traffic over shortest paths in a distributed fashion. Actually, comparing to OSPF, SPEF only needs one more weight for each link and provably achieves optimal TE. Numerical experiments have been done to compare SPEF with the current version of OSPF, showing the effectiveness of SPEF in terms of link utilization and network load distribution.