LANCIN , Aurélien

This thesis considers routing issues in networks, and particularly the graph of the autonomous systems (AS) of the Internet. Firstly, we aim at better understanding the properties of the Internet that are useful in the design of new routing paradigms. Secondly, we want to evaluate by simulation the performance of these paradigms. The first part...

The expansion of Internet topology, which comprises thousands of Autonomous Systems (AS), has resulted in a number of important research challenges. The Border Gateway Protocol (BGP), which is used to make core routing decisions on the Internet, starts to show its limitations in terms of the number of routing table entries it can store locally,...

The expansion of Internet topology, which comprises thousands of Autonomous Systems (AS), has resulted in a number of important research challenges. The Border Gateway Protocol (BGP), which is used to make core routing decisions on the Internet, starts to show its limitations in terms of the number of routing table entries it can store locally,...

Nous proposons un algorithme simple et efficace pour calculer l'hyperbolicité de grands graphes dont la complexité temporelle est fonction de la distribution des plus courts chemins dans les composantes biconnexes du graphe et de la valeur de l'hyperbolicité. Nous montrons également comment réduire la taille de l'instance en utilisant une...

Let G be a connected graph, and let d(a, b) denotes the shortest path distance between vertices a and b of G. The graph G is δ-hyperbolic if for any vertices a, b, c, d of G, the two largest of the three sums S1 = d(a,b) + d(c,d), S2 = d(a,c) + d(b,d), and S3 = d(a,d) + d(b,c) differ by at most 2δ. This can be determined in time O(n^4) which...

The Gromov hyperbolicity is an important parameter for analyzing complex networks which expresses how the metric structure of a network looks like a tree. It is for instance used to provide bounds on the expected stretch of greedy-routing algorithms in Internet-like graphs. However, the best known theoretical algorithm computing this parameter...

The shortest-path metric d of a connected graph G is δ-hyperbolic if, and only if, it satisfies d(u, v)+d(x, y) ≤ max{d(u, x)+d(v, y), d(u, y)+d(v, x)}+2δ, for every 4-tuple u, x, v, y of G. We investigate some relations between the hyperbolicity of a graph and the hyperbolicity of its atoms, that are the subgraphs resulting from the...

Given a graph, its hyperbolicity is a measure of how close its distance distribution is to the one of a tree. This parameter has gained recent attention in the analysis of some graph algorithms and the classification of complex networks. We study on practical improvements for the computation of hyperbolicity in large graphs. Precisely, we...

Grph is an open-source Java library for the manipulation of graphs. Its design objectives are to make it portable, simple to use/extend, computationally/memory efficient, and, according to its initial motivation: useful in the context of graph experimentation and network simulation. Grph also has the particularity to come with tools like an...

The Autonomous System (AS)-level topology of the Internet that currently comprises 40k ASs, is growing at a rate of about 10% per year. In these conditions, Border Gateway Protocol (BGP), the inter-domain routing protocol of the Internet starts to show its limits, among others in terms of the number of routing table entries it can dynamically...

The Autonomous System (AS) topology of the Internet (up to 61k ASs) is growing at a rate of about 10% per year. The Border Gateway Protocol (BGP) starts to show its limits in terms of the number of routing table entries it can dynamically process and control. Due to the increasing routing information processing and storage, the same trend is...