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You are here: Home / Agenda / Seminars / Thesis defense NGUYEN Huu-Nghi

Thesis defense NGUYEN Huu-Nghi

Passive methods on the Standard Deviation of the End-to-End delays
When Mar 09, 2017
from 02:00 to 04:00
Where Salle de Thèse de l'ENS de Lyon
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The defense will be in French.
Jury :
  • Mme. Tülin BERBER ATMACA, professeur des universités à Télécom SudParis - Rapporteur
  • M.      Steven MARTIN, professeur des universités à l’Université Paris-Sud - Rapporteur
  • Mme. Katia JAFFRÈS-RUNSER, maître de conférences à l’Université de Toulouse - Examinateur
  • M.      Congduc PHAM, professeur des universités à l’Université de Pau - Examinateur
  • Mme. Isabelle GUÉRIN-LASSOUS, professeur des universités à l’Université Lyon 1 - Directrice de thèse
  • M.      Thomas BEGIN, maître de conférence à l’Université Lyon 1 - Co-encadrement de thèse
  • M.      Anthony Busson, professeur des universités à l’Université Lyon 1 - Co-encadrement de thèse (invité)
Thesis abstract :
Since the early beginning of Internet, the amount of data exchanged over the networks has exponentially grown. The devices deployed on the networks are very heterogeneous, because of the growing presence of middleboxes (e.g., firewalls, NAT routers, VPN servers, proxy). The algorithms run on the networking devices (e.g., routing, spanning tree) are often complex, closed, and proprietary while the interfaces to access these devices typically vary from one manufacturer to the other.
All these factors tend to hinder the understanding and the management of networks.
Therefore a new paradigm has been introduced to ease the design and the management of networks, namely, the SDN (Software-defined Networking). In particular, SDN defines a new entity, the controller that is in charge of controlling the devices belonging to the data plane. Thus, in a SDN-network, the data plane, which is handled by networking devices called virtual switches, and the control plane, which takes the decisions and executed by the controller, are separated. In order to let the controller take its decisions, it must have a global view on the network. This includes the topology of the network and its links capacity, along with other possible performance metrics such delays, loss rates, and available bandwidths. This knowledge can enable a multi-class routing, or help guarantee levels of Quality of Service.
The contributions of this thesis are new algorithms that allow a centralized entity, such as the controller in an SDN network, to accurately estimate the end-to-end delay for a given flow in its network. The proposed methods are passive in the sense that they do not require any additional traffic to be run. More precisely, we study the expectation and the standard deviation of the delay. We show how the first moment can be easily computed. On the other hand, estimating the standard deviation is much more complex because of the correlations existing between the different waiting times. We show that the proposed methods are able to capture these correlations between delays and thus providing accurate estimations of the standard deviation of the end-to-end delay. Simulations that cover a large range of possible scenarios validate these results.