References of "Balon, Simon"
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See detailBGP-aware IGP Link Weight Optimization in Presence of Route Reflectors
Balon, Simon ULg; Leduc, Guy ULg

in IEEE INFOCOM 2009 (2009, April)

The first generation of IGP Link Weight Optimizers (LWOs) was based on presumably invariant intra-domain traffic matrices only, ignoring the fact that updating link weights had a side effect on these ... [more ▼]

The first generation of IGP Link Weight Optimizers (LWOs) was based on presumably invariant intra-domain traffic matrices only, ignoring the fact that updating link weights had a side effect on these traffic matrices due to hot-potato routing, thus result- ing in suboptimal link weight settings, and sometimes to very bad performance. The second generation of IGP LWOs, referred to as BGP-aware LWOs, has been able to optimize link weights while taking hot-potato effects into account. However, these tools relied on the complete visibility assumption fulfilled by e.g. a full-mesh iBGP configu- ration. This paper proposes a third generation LWO, still BGP-aware, but also able to work with iBGP con- figurations based on route reflectors, which usually hide some reachability information from routers. This partial visibility may cause various problems, including path deflections (i.e., the actual egress router is not the expected one), which may in turn create forwarding loops. Our LWO embeds a BGP routing solver which can always predict the actual egress router, even when route reflectors are used. It can also forbid solutions leading to path deflection. Its efficiency is evaluated on a real dataset, and compared to other LWOs. [less ▲]

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See detailCombined Intra- and Inter-domain Traffic Engineering using Hot-Potato Aware Link Weights Optimization
Balon, Simon ULg; Leduc, Guy ULg

in ACM SIGMETRICS Performance Evaluation Review (2008), 36(1), 441-442

A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach ... [more ▼]

A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach is inadequate because it ignores a potential impact on interdomain routing due to hot-potato routing policies. This may result in changes in the intradomain traffic matrix that have not been anticipated by the link weights optimizer, possibly leading to degraded network performance. <br /> <br />We propose a BGP-aware link weights optimization method that takes these hot-potato effects into account. This method uses the interdomain traffic matrix and other available BGP data, to extend the intradomain topology with external virtual nodes and links, on which all the well-tuned heuristics of a classical link weights optimizer can be applied. Our method can also optimize the traffic on the interdomain peering links. [less ▲]

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See detailCan Forwarding Loops Appear when Activating iBGP Multipath Load Sharing?
Balon, Simon ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2007, November), 4866

We analyse the possible consequences of activating iBGP multipath load sharing in a given domain (or AS), which allows for load balancing over multiple exit routers. It has been stated that interdomain ... [more ▼]

We analyse the possible consequences of activating iBGP multipath load sharing in a given domain (or AS), which allows for load balancing over multiple exit routers. It has been stated that interdomain routing loops may appear in this case. We show that under reasonable assumptions (which reflect commercial relationships between ASes) such routing loops cannot appear. Furthermore we show that even if theses assumptions are not met, routing loops can only be transient. [less ▲]

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See detailTraffic Engineering an Operational Network with the TOTEM Toolbox
Balon, Simon ULg; Lepropre, Jean; Delcourt, Olivier et al

in IEEE Transactions on Network and Service Management (2007), 4(1), 51-61

We explain how the TOTEM toolbox can be used to engineer an operational network. TOTEM is an open source TOolbox for Traffic Engineering Methods which covers IP-based and MPLS-based intradomain traffic ... [more ▼]

We explain how the TOTEM toolbox can be used to engineer an operational network. TOTEM is an open source TOolbox for Traffic Engineering Methods which covers IP-based and MPLS-based intradomain traffic engineering (TE) algorithms, but also interdomain TE. In this paper, we use the toolbox as an off-line simulator to optimise the traffic of an operational network. To help an operator to choose between an IP-based or MPLS-based solution, or to find the best way to load-balance a network for a given traffic, our case study compares several IP and MPLS routing algorithms, evaluates the impact of hot-potato routing on the intradomain traffic matrix, and analyses the worst-case link failure. This study reveals the power of a toolbox that federates many traffic engineering algorithms. [less ▲]

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See detailA scalable and decentralized fast-rerouting scheme with efficient bandwidth sharing
Balon, Simon ULg; Mélon, Laurent; Leduc, Guy ULg

in Computer Networks (2006), 50(16), 3043-3063

This paper focuses on the protection of virtual circuits (Label Switched Paths, LSPs) in a (G)MPLS (Generalised Multi-Protocol Label Switching) network. The proposed algorithm is designed to protect ... [more ▼]

This paper focuses on the protection of virtual circuits (Label Switched Paths, LSPs) in a (G)MPLS (Generalised Multi-Protocol Label Switching) network. The proposed algorithm is designed to protect traffic with strong delay requirements such as EF (Expedited Forwarding) ordered aggregates in a DiffServ domain. Indeed, for this type of application, we need fast restoration in case of failure. The duplication of all the packets in a 1 + 1 end-to-end restoration scheme consumes a large amount of bandwidth. Furthermore, end-to-end recovery with bandwidth sharing schemes are usually considered to be far too slow. Local fast-rerouting is a solution which can compete with restoration times and bandwidth consumption offered by SONET self-healing rings. Our scheme includes a sophisticated resource aggregation mechanism based on the concepts of "backup-backup aggregation" and "backup-primary aggregation". The path selection algorithm is also designed to efficiently reduce the resource usage. Moreover, when considering LSPs at different preemption levels, our algorithm is able to correctly calculate the amount of bandwidth that can be preempted despite the sharing of resource. We show that our approach, though local, can compete with the state-of-the-art end-to-end recovery schemes in terms of resource consumption. The major contribution of our scheme, the "backup-primary aggregation", was then also used in the context of end-to-end recovery and improved its performance substantially. To be able to save a maximum amount of bandwidth in a decentralised implementation, the nodes that compute backup LSPs need to obtain a certain amount of link-state information. We propose a solution where the nodes learn almost all the information they need with RSVP messages. This drastically reduces the information that needs to be flooded in the whole network and is the first scalable decentralised solution capable of sharing a large amount of bandwidth. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailA scalable heuristic for hybrid IGP/MPLS traffic engineering - Case study on an operational network
Skivée, Fabian; Balon, Simon ULg; Leduc, Guy ULg

in 14th IEEE International Conference on Networks (2006, September)

In current IP networks, a classical way to achieve traffic engineering is to optimise the link metrics. This operation cannot be done too often and can affect the route of a lot of traffic. Multiprotocol ... [more ▼]

In current IP networks, a classical way to achieve traffic engineering is to optimise the link metrics. This operation cannot be done too often and can affect the route of a lot of traffic. Multiprotocol Label Switching (MPLS) opens new possibilities to address the limitations of IP systems concerning traffic engineering thanks to explicit label-switched paths (LSPs). This paper proposes a new method based on simulated annealing meta-heuristic to compute a set of LSPs that optimise a given operational objective. The hybrid IGP/MPLS approach takes advantage of both IP and MPLS technologies and provides a flexible method to traffic engineer a network on a day to day basis. We illustrate the capabilities of our method with some simulations and a comparison with other techniques on an existing operational network. The results obtained by setting up a small number of LSPs are nearly optimal and better than by engineering the IGP weights. Moreover, although it could be combined with a static setting of the latter, SAMTE alone gives already the same results as this combination in much less CPU time, which thus allows an administrator to keep its initial and meaningful IGP metrics in his network. [less ▲]

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See detailDividing the Traffic Matrix to Approach Optimal Traffic Engineering
Balon, Simon ULg; Leduc, Guy ULg

in 14th IEEE International Conference on Networks (2006, September)

In this paper we propose a new method to approach optimal Traffic Engineering routing. The method consists of dividing the traffic matrix into $N$ sub-matrices, called strata, and route each of these ... [more ▼]

In this paper we propose a new method to approach optimal Traffic Engineering routing. The method consists of dividing the traffic matrix into $N$ sub-matrices, called strata, and route each of these independently. We propose two different implementations of our method in routers. Our method can also be used to compute a very precise approximation of the optimal value of a given objective function for comparison to heuristic Traffic Engineering algorithms. For this application, our algorithm is very efficient on large topologies compared to an LP formulation. [less ▲]

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See detailHow well do traffic engineering objective functions meet TE requirements?
Balon, Simon ULg; Skivée, Fabian ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2006, May), 3976

We compare and evaluate how well-known and novel networkwide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem ... [more ▼]

We compare and evaluate how well-known and novel networkwide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem as a linear program and solve it to optimality, thus finding for each objective function the best possible target of any heuristic TE algorithm. We show that all the objective functions are not equivalent and some are far better than others. Considering the preferences a network operator may have, we show which objective functions are adequate or not. [less ▲]

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See detailTOTEM: A Toolbox for Traffic Engineering Methods
Lepropre, Jean; Balon, Simon ULg; Leduc, Guy ULg

Poster (2006, April)

In this document, we propose a demonstration of TOTEM, a TOolbox for Traffic Engineering Methods. This toolbox integrates a series of tools for intra-domain and inter-domain traffic engineering of IP and ... [more ▼]

In this document, we propose a demonstration of TOTEM, a TOolbox for Traffic Engineering Methods. This toolbox integrates a series of tools for intra-domain and inter-domain traffic engineering of IP and MPLS networks. It provides an open source software that allows an operator to test methods coming from the academic research. A researcher can also use the toolbox to compare and promote new TE algorithms. The toolbox is designed to be deployed either as an on-line tool in an operational network, or as an off-line traffic engineering simulator. [less ▲]

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See detailAn open source traffic engineering toolbox
Leduc, Guy ULg; Abrahamsson, Henrik; Balon, Simon ULg et al

in Computer Communications (2006), 29(5), 593-610

We present the TOTEM open source Traffic Engineering (TE) toolbox and a set of TE methods that we have designed and/or integrated. These methods cover intra-domain and inter-domain TE, IP-based and MPLS ... [more ▼]

We present the TOTEM open source Traffic Engineering (TE) toolbox and a set of TE methods that we have designed and/or integrated. These methods cover intra-domain and inter-domain TE, IP-based and MPLS-based TE. They are suitable for network optimisation, better routing of traffic for providing QoS, load balancing, protection and restoration in case of failure, etc. The toolbox is designed to be deployed as an on-line tool in an operational network, or used off-line as an optimisation tool or as a traffic engineering simulator. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailComparing traffic engineering objective functions
Balon, Simon ULg; Skivée, Fabian; Leduc, Guy ULg

in CoNext 2005 - Student Workshop (2005, October)

We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem ... [more ▼]

We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem as a linear program and solve it to optimality, thus finding for each objective function the best possible target of any heuristic TE algorithm. Our first results suggest that they can give quite different results. [less ▲]

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See detailArchitecture d'une boîte à outils d'algorithmes d'ingénierie de trafic et application au réseau GEANT
Skivée, Fabian; Balon, Simon ULg; Delcourt, Olivier et al

in Ingénierie des protocoles - Qualité de service, multimédia et mobilité (2005, March)

This paper presents the software architecture of a traffic engineering toolbox. The methods already included cover MPLS-based intra-domain traffic engineering (TE), but will soon cover IP-based TE and ... [more ▼]

This paper presents the software architecture of a traffic engineering toolbox. The methods already included cover MPLS-based intra-domain traffic engineering (TE), but will soon cover IP-based TE and inter-domain TE. This toolbox provides an open source software that allows an operator to test methods coming from the academic research. A researcher can also use the toolbox for comparing and promoting his/her TE algorithms. The toolbox is designed to be deployed as an on-line tool in a operational network or as a traffic engineering simulator. We present a case study of traffic optimisation on the GÉANT network that compares different routing algorithms, evaluates different protection cost, and analyses the worst-case link failure. [less ▲]

Detailed reference viewed: 72 (8 ULg)