Initiative in Innovative Computing @ Harvard

Seminar Series

Wednesday, April 25, 2007; 4:00pm

Srinidhi Varadarajan, Director, Center for High-End Computing Systems, Associate Professor of Computer Science, Virginia Polytechnic Institute and State University

Seminar Title: Relativistic Time: A Unified Temporal Model for Mixed-Mode Simulations

Abstract

As computer networks continue to grow dramatically, there is a critical need for scalable network simulation testbeds that can capture the complexity of large-scale systems. To this end, we developed the Open Network Emulator, a scalable testbed that supports both discrete-event simulation as well as direct-code execution based emulation of Internet-scale networks.

The scale and fidelity of this simulation environment present a fundamental challenge. As the complexity of a simulation system starts approaching reality, there is no unified measure of time. Network applications in a real system run in real-time or wall-clock time, which flows naturally, but is uncontrolled. Models of next generation network devices operate in highly controllable virtual time, but the virtual clock has to be forced by events occurring in the system.

To solve this problem, we developed a system of time called relativistic time, which reconciles real time and virtual time by creating a model of time that flows naturally, and yet is highly controllable.

In this talk, I will present the characteristics of the simulation environment, the challenges in integrating temporal models and results from our work on the relativistic time model.

Upcoming IIC seminars

Continue to stay up to date with our IIC Seminar Schedule.

Parking is available in the 52 Oxford Street Garage. Please tell the attendant that you are attending the IIC Seminar.