Achieving near-optimal traffic engineering solutions for current OSPF/IS-IS networks

Abstract

Traffic engineering is aimed at distributing traffic so as to "optimize" a given performance criterion. The ability to carry out such an optimal distribution depends on both the routing protocol and the forwarding mechanisms in use in the network. In IP networks running the OSPF or IS-IS protocols, routing is over shortest paths, and forwarding mechanisms are constrained to distributing traffic uniformly over equal cost shortest paths. These constraints often make achieving an optimal distribution of traffic impossible. In this paper, we propose and evaluate an approach, based on manipulating the set of next hops for routing prefixes, that is capable of realizing near optimal traffic distribution without any change to existing routing protocols and forwarding mechanisms. In addition, we explore the tradeoff that exists between performance and the overhead associated with the additional configuration steps that our solution requires. The paper's contributions are in formulating and evaluating an approach to traffic engineering for existing IP networks that achieves performance levels comparable to that offered when deploying other forwarding technologies such as MPLS. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This conference paper is available at ScholarlyCommons: http://repository.upenn.edu/ese_papers/26Achieving Near-Optimal Traffic Engineering Solutions for Current OSPF/IS-IS NetworksAbstract-Traffic engineering is aimed at distributing traffic so as to "optimize" a given performance criterion. The ability to carry out such an optimal distribution depends on both the routing protocol and the forwarding mechanisms in use in the network. In IP networks running the OSPF or IS-IS protocols, routing is over shortest paths, and forwarding mechanisms are constrained to distributing traffic uniformly over equal cost shortest paths. These constraints often make achieving an optimal distribution of traffic impossible. In this paper, we propose and evaluate an approach, based on manipulating the set of next hops for routing prefixes, that is capable of realizing near optimal traffic distribution without any change to existing routing protocols and forwarding mechanisms. In addition, we explore the tradeoff that exists between performance and the overhead associated with the additional configuration steps that our solution requires. The paper's contributions are in formulating and evaluating an approach to traffic engineering for existing IP networks that achieves performance levels c...

Adaptive Multi-topology IGP Based Traffic Engineering with Near-Optimal Network Performance

“…Some variations of this TE algorithm were also designed to obtain a set of link weights that is robust to traffic demand uncertainty [11] and link failures [12]. Sridharan et al [3] revealed that near-optimal TE solutions can be achieved by carefully assigning traffic to some selected next-hops over ECMP paths at each eligible router. By modifying the next-hop entry in the forwarding table of a limited number of routers, uneven traffic splitting based on individual routing prefixes can be emulated.…”

“…Once the optimized MT-IGP link weights have been configured in the network, dynamic traffic control through traffic splitting at source nodes can be performed through the provisioned diverse IGP paths. Arbitrary traffic splitting is usually required for achieving optimal TE performance [2,3,5]. However, in plain OSPF/IS-IS networks, this prerequisite is not possible since these protocols only allow equal traffic splitting onto multiple equal cost paths.…”

“…Intra-domain Traffic Engineering (TE) based on IGPs such as OSPF and IS-IS has recently been receiving numerous attentions in the Internet research community [1][2][3][4][5]. In order to achieve near-optimal or even optimal network performance, it is suggested that both IGP link weights and traffic splitting ratio need to be optimized simultaneously [2,3,5] based on the traffic matrix (TM) and the network topology as input.…”

“…In order to achieve near-optimal or even optimal network performance, it is suggested that both IGP link weights and traffic splitting ratio need to be optimized simultaneously [2,3,5] based on the traffic matrix (TM) and the network topology as input. However, this is only applicable to offline TE where knowledge of the estimated TM is assumed a priori.…”

OSPF routing with optimal oblivious performance ratio under polyhedral demand uncertainty

“…In order to tackle this difficulty, either the single path routing assumption or a couple of alternative strategies like the management of next hop selection or edge-based traffic engineering have been used. We cite Bley and Koch (2002), Lin and Wang (1993), and Tomaszewski et al (2005) as examples for unsplit routing while we refer to Parmar et al (2009), Sridharan et al (2003), and Wang et al (2005) for the latter case. Broström and Holmberg (2005), De Giovanni et al (2005), Parmar et al (2009), Pióro et al (2002), and Tomaszewski et al (2005) also show mixed-integer modeling examples for incorporating the ECMP rule.…”