Samrat Ganguly

Path provisioning for service level agreements in Differentiated Services networks

We study the path provisioning as a mechanism to deliver service level agreements in IP Differentiated Services networks. There is no known polynomial time solution for this problem, so we propose and analyze (by simulations) several heuristic algorithms for solving the problem. As our simulations demonstrate, a centralized server consistently delivers a better performance than a distributed solution. We also show that the performance of one of the proposed algorithms, the greedy algorithm with backtracking, can be very close to the optimal one, while being computationally feasible.

Measurement-based approaches for accurate simulation of 802.11-based wireless networks

In this work, we address the issue of unrealistic simulations of wireless networks using a measurement-based approach. The idea is to use empirical modeling using measurement data as a mechanism to model physical layer behavior. We demonstrate the power of this approach for 802.11-based networks using ns2, a packet-level network simulator. Specifically, we develop two versions of the ns2 simulator that model the wireless physical layer with different levels of fidelity. In both versions, the deferral and reception model are built using measurements. For propagation modeling, one version uses direct measurements and the other uses an empirically derived model. In validation experiments with a 12-node mesh testbed, both these versions were found to be reasonably accurate (85 percentile errors within about 10% of the capacity) relative to regular simulations (85 percentile errors within 50% of capacity).

Channel assignment for wireless meshes with tree topology

The capacity of wireless mesh networks can be enhanced with judicious channel assignment. This paper deals with one particular type of mesh network topology - the tree topology. The unique characteristics of this topology is that all the traffic to/from the mesh nodes goes through the root. This enables design of an efficient channel allocation algorithm that utilizes the intrinsic characteristics of the tree topology and the traffic pattern over this topology. We use the unique connection characteristics of the tree topology to create an auxiliary contention graph over which we execute our coloring algorithm. This mitigates the burden of ensuring connectivity that channel allocation algorithms for mesh have to consider and the algorithm can solely focus on the task of capacity maximization. Our algorithm has a low complexity of O(N2) for a mesh network with N nodes.

ACM workshop on mobile video delivery

It gives us great pleasure in bringing to you the third edition of the International Workshop on Mobile Video Delivery (MoViD 2010) that is being held in conjunction with ACM Multimedia 2010 on 25 October in Florence, Italy. Following the success of the past workshops in this series (MoViD 2009 in conjunction with IEEE Infocom 2009 held at Rio De Janeiro, Brazil, and MoViD 2008 held in conjunction with IEEE WoWMoM at Newport Beach, California), MoVid 2010 aims to foster interaction among researchers and industry experts in exchanging new ideas by bringing together members of the content, systems and networking communities with a specific focus on enhancing the support of video content on mobile networks.