Job opportunities
PhD positions - 2016
Multi-path in networks: detection and evaluation of performance
Advisors: Cristel Pelsser, Stéphane Cateloin, Pascal Mérindol
The first objective will be to develop measurement techniques to detect, quantify and characterize multipath in today’s Internet. To measure the performance observed by applications in a multipath environment and understand the different forms of multi-path is a second objective for this work. For this purpose, the student will develop correlation techniques in order to pinpoint the paths used by a flow and the performance of its paths.
We will subsequently draw conclusions from our measurements. Based on our observations, we will determine whether there are aspects of multipath routing that need to be improved. We may develop techniques to avoid path segments incurring degraded performance. This may require changes in the signaling of routing information, in the computation and use of the paths in order to spread traffic dynamically upon changes in load. The objective is to nevertheless provide a stable routing solution that avoids the negative effects of route oscillations.
The PhD student will elaborate methods to correlate changes in the control plane with performance degradation. If she/he observes that some actions of the network operators are detrimental to the performance, the student will propose efficient network maintenance techniques that are exempt of problems in a multi-path context.
Finally, we will study which properties can make multipath routing protocols more robust to changes than single path environments. Which physical topologies meet robustness requirements? How to design iBGP topologies?
To apply, please send your full CV, academic record, recommendation(s) and supporting letter before may 20 2016 to pelsser@unistra.fr.
PhD positions - 2014
Advisors : Fabrice Theoleyre, Stéphane Cateloin, Pascal Mérindol
To apply, please send your full CV, academic record, recommendation(s) and supporting letter before may 15 2013 to cateloin@unistra.fr,merindol@unistra.fr.
PhD positions - 2013
Multipath routing and collaborative load balancing
Advisors : Thomas Noël, Jean-Jacques Pansiot, Stéphane Cateloin
Load balancing is a decision process that may be based on indicators which are local or received from other routers. The nature of these indicators should be adapted according to the context in which they are employed (wireless networks, sensor networks, code networks...). Variables relating to the quality of service could also come into consideration, for example by assigning real-time flows to one or more paths respecting specific constraints.
The main objective of this thesis is to focus on the collaboration between routers, which relies on an exchange of messages. These messages can be upstream requests such as throughput reduction ("backpressure messages"), messages allowing the admission of new flows , or disseminating information relating to the current conditions of routers (e.g. radio links quality, position and speed of a mobile node, or its battery level).
The qualitative or quantitative nature of the data exchanged, the triggers of these messages, their rate, and the action to be taken upon receipt are all behaviors to define and study. The candidate will have to evaluate the solutions he proposes, using simulation tools. Besides the quality of the distribution, convergence is a crucial point. The performance analysis will determine whether the proposed solutions are constantly evolving in an unstable state or whether tend towards an acceptable steady solution. In this case, the convergence time is an important indicator.
To apply, please send your full CV, academic record, recommendation(s) and supporting letter before may 15 2013 to cateloin@unistra.fr.
Internet Service Provider Networks & Multi-Path Routing
Advisors : Thomas Noël, Jean-Jacques Pansiot, Pascal Mérindol
- A Thesis subject "Internet Service Provider Networks & Multi-Path Routing" is available here: Models, IP Graphs & Routing . Please contact us to apply before may 15 2013.
Networks operators must ensure a certain degree of connectivity to their customers. This induces specific patterns that structure the underlying graph, in particular the assurance of minimum redundancy. Another problem in networks of operators is their resources optimization. This objective can be implemented with multipath routing. It is one of the possible solutions to distribute the load in the network and limit congestions. The objective of this thesis is to investigate the relationships linking the graph structure of IP networks and the opportunity to efficiently develop and deploy a multipath routing protocol. The issue of valuation is then prevalent: is it easier to evaluate the valuation modification or overcome this logical overlay and then only rely on the physical structure? Is it possible to say a priori, and knowing the topological characteristics of a network, what algorithm multipath routing protocol is most effecient? Conversely, can we, given a routing algorithm, infer appropriate graph models , which favor it efficiency? Are there IP networking patterns that hamper the establishment of multiple routes or, conversely, are there any structural and logical patterns that tend to favor it?
Past positions
- 2012 - Our group proposes a PhD student position (Profile). Please, contact us for any further information.