PFAN Scientific Event on Tuesday, 29 August 2017 at 3:30 pm NUST-SEECS, H-12, Islamabad



NUST-SEECS is organizing a seminar by two French professors, who are visiting NUST for a collaboration project under PHC Peridot program, funded by the Govt. of France and HEC. The seminar will have two talks, of half-an-hour each, on specific research topics. Then some recent research trends in computer networks will be discussed, followed by a questionanswer session.

Intended Audience / Registration:

The seminar is intended for people with background in networks. Researchers and students from relevant fields are welcome to attend this seminar.

Talk 1: A New Approach for Association in WiFi Networks

Highly dense deployments of Wi-Fi networks has led to the possibility for a node to choose between several access points (APs), improving coverage, wireless links quality, and mobility. However, this density of access points may generate interference, contention and eventually decreases the overall throughput, as these APs have to share a limited number of channels. The recent trend where Wi-Fi networks are managed in a centralized way offers the opportunity to alleviate this problem through a global optimization of the resource usage. In particular, optimizing the association step between APs and stations can increase the overall throughput and fairness between stations. In this talk, an original solution to this optimization problem will be discussed. This solution is based on a mathematical model that aims to evaluate and forecast the throughput obtainable for each station for a given association, and on a heuristic based on a local search algorithm to find approximate solutions. This latter approach has the benefit to be tuned according to the CPU and time constraints of the WLAN controller. The proposed solution is compared with different heuristics and evaluated under the network simulator NS-3.

About the Speaker:

Professor Dr Isabelle Guerin Lassous has received her PhD in computer science from University of Paris - Diderot (Paris 7) in 1999. She was an INRIA researcher from 2000 to 2006. She has been a professor at the Université Claude Bernard Lyon 1, France and also working at LIP (ENSL, CNRS, UCBL, INRIA), Lyon, France, since September 2006. Her research interests include computer networks, wireless networks, and distributed algorithms. She is also in the editorial board of two Elsevier journals (Computer Communications and Ad Hoc Networks), and also involved in several technical program committees of ACM and IEEE conferences.

Talk 2: Performance Modeling of Virtual Switching Systems

In an SDN/NFV-enabled network, the behavior of virtual switches is a major concern in determining the overall network performance. The prominent open-source solution for virtual switching is Open vSwitch while the DPDK library has been developed to accelerate the packet processing. In this talk, a general framework is presented for the modeling and the analysis of DPDK-based virtual switches, taking into account the switch-over times (amount of time needed for a CPU core to switch from one input queue to another). The model delivers performance metrics such as the buffer occupancy, the loss rate and the sojourn time of a packet in RX queues. The new model is also compared with two existing models. Numerical results show that the model combines the accuracy of one model and the efficiency of the other.

About the Speaker:

Dr Thomas Begin received a degree in Electronics Engineering from ISEP (Paris) in 2003, and Masters and Ph.D. degree in Computer Science from Université Pierre et Marie Curie (Univ. of Paris 6) in 2005 and 2008, respectively. He was a post-doctoral fellow at University of California Santa Cruz in 2009. Since 2009, he is Assistant Professor at Université Claude Bernard Lyon 1, France, in the Computer Science department. During the academic year 2016-2017, he was an invited researcher at University of Ottawa, Canada. Dr Thomas Begin research interests are in performance evaluation, computer network, and system modeling. His principal applications pertain to high-level modeling, wireless networks, resource allocation and queuing systems.