Abstract

We have developed a new traffic measuring tool and applied it to the real-time simulation of a network. It monitors IP traffic on an ATM link and continuously transfers the length and timestamp of each IP packet to a post-processing system. The post-processing system receives the data, estimates the cell's arrival epoch at the transmission queue of the ATM link, and simulates the queueing behavior on-line if conditions differ from those of the actual system. The measuring tool and real-time simulation rep resent a new approach to traffic engineering. A new estimation problem, the arrival sequence estimation, is shown and some algorithms are proposed and evaluated. Document type: Part of book or chapter of book

Abstract

This study uses regression analysis to evaluate long-run traffic management system performance. Three important traffic management systems in the Twin Cities metro area - Ramp Metering, Variable Message Signs (VMS), and Freeway Service Patrol (the Highway Helper Program) were evaluated with multiple regression models to predict link speed and incident rate. We find that ramp meters increase freeway link speed and reduce incident rate. Freeway Service Patrols increase link speed when incidents are present. The results for variable message signs are ambiguous. Document type: Part of book or chapter of book

Abstract

In the Internet, the traffic crosses between two to eight autonomous systems before reaching its destination. Consequently, end-to-end quality of service requires provisioning across more than one domain. This paper proposes a new scheme for introducing MPLS technology into an inter-domain environment. Results obtained using the OPNET simulation platform show that extending MPLS across AS boundaries can improve the QoS perceived by the end users. This means that inter-domain traffic engineering is a promising solution for a QoS aware Internet. Document type: Part of book or chapter of book

Abstract

We consider the problem of allocating bandwidth to competing flows in an MPLS network, subject to constraints on fairness, efficiency, and administrative complexity. The aggregate traffic between a source and a destination, called a flow, is mapped to label switched paths (LSPs) across the network. Each flow is assigned a preferred ('primary') LSP, but traffic may be sent to other ('secondary') LSPs. Within this context, we define objectives for traffic engineering, such as fairness, efficiency, and preferred flow assignment to the primary LSP of a flow ('Primary Path First', PPF). We propose a distributed, feedback-based multipath routing algorithm that attempts to apply additive-increase and multiplicative-decrease (AIMD) to implement our traffic engineering objectives. The new algorithm is referred to as multipath-AIMD. We use ns-2 simulations to illustrate the fairness criteria and PPF property of our multipath-AIMD scheme in an MPLS network. Document type: Part of book or chapter of book

Abstract

This paper proposes an integrated network management framework for inter-domain outbound traffic engineering. The framework consists of three functional blocks (monitoring, optimization and implementation) to make the outbound traffic engineering adaptive to network condition changes such as inter-domain traffic demand variation, inter-domain routing changes and link failures. The objective is to keep the inter-domain link utilization balanced under any of these changes while reducing service disruptions and reconfiguration overheads. Simulation results demonstrate that the proposed framework can achieve better load balancing with less service disruptions and re-configuration overheads in comparison to alternative approaches. Document type: Part of book or chapter of book

Abstract

Peer-to-peer networking enjoys euphoric support and fierce resistance simultaneously, and for the same reasons. It presents a model where decentralization and lack of structure, hierarchy and control are promoted. Although significant research is carried out to tackle individual issues arising from that paradigm, there has been no obvious approach for evening out differences on a more general basis. In this paper we introduce a framework and provide implementation techniques for such an approach. The framework aims at integrating partial techniques that solve individual problems and has been designed for flexibility. The integrated approach we are proposing includes forming and maintaining of peer-to-peer overlays, controlling the underlying topology being formed, limiting the signaling traffic being generated and optimizing the payload traffic. Document type: Part of book or chapter of book

Abstract

The GMPLS standardization is paving the way for new configurable Traffic Engineering (TE) policies and new survivability schemes for transport networks. In this context, a centralized Path Computation System (PCS) has been implemented, suited for transport networks with a GMPLS control plane. After a brief description of the requirements for a PCS in a GMPLS network, some design issues for the proposed implementation are drawn, with particular emphasis on the centralized approach and on the strategies for achieving the connection survivability. Some results of an intensive testing campaign are shown for the validation of the design choices. Document type: Part of book or chapter of book

Abstract

In INterdomain Ingress Traffic Engineering (INITE), a “target” Autonomous System (AS) aims to control the ingress link at which the traffic of one or more upstream source networks enters that AS. In practice, ISPs often manipulate, mostly in a trial-and-error manner, the length of the AS-Path attribute of upstream routes through a simple technique known as prepending (or padding). In this paper, we focus on prepending and propose a polynomial-time algorithm (referred to as OPV) that determines the optimal padding for an advertised route at each ingress link of the target network. Specifically, given a set of “elephant” source networks and some maximum load constraints on the ingress links of the target AS, OPV determines the minimum padding at each ingress link so that the load constraints are met, when it is feasible to do so. OPV requires as input an AS-Path length estimate from each source network to each ingress link. We describe how to estimate this matrix, leveraging the BGP Looking Glass Servers. To deal with unavoidable inaccuracies in the AS-Path length estimates, and also to compensate for the generally unknown BGP tie-breaking process in upstream networks, we also develop a robust variation (RPV) of the OPV algorithm. Document type: Part of book or chapter of book

Abstract

Part 1: Autonomic and Decentralized Management International audience Energy efficiency has become a major research topic in the Internet community as a result of unprecedented rise in the Information and Communication Technology (ICT) sector. One typical approach towards energy efficiency is to select a subset of IP routers or interfaces that will go to sleep mode during the off-peak period. However, on-the-fly network reconfiguration is generally deemed harmful especially to real time packets due to routing re-convergence. In this paper, we develop an efficient algorithm for achieving energy efficiency which is disruption free. The objective is to incrementally wake up sleeping links upon the detection of increased traffic demand. Unlike normal approaches of manipulating link weights or reverting to full topology in case of even minor network congestion and thereby sacrificing energy savings, our algorithm wakes up the minimum number of sleeping links to the network in order to handle this dynamicity. The performance of our algorithm was evaluated using the GEANT network topology and its traffic traces over a period of one week. According to our simulation results, up to almost 47% energy gains can be achieved without any obstruction to the network performance. Secondly, we show that the activation of a small number of sleeping links is still sufficient to cope with the observed traffic surge. Document type: Part of book or chapter of book