טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentCohen Itamar
SubjectT-Plots: A Novel Approach to Network Design
DepartmentDepartment of Electrical Engineering
Supervisor Professor Isaac Keslassy
Full Thesis textFull thesis text - English Version


Abstract

It is accepted wisdom that changes in the traffic matrix entail capacity over-provisioning, but there is no simple measure of just how much over-provisioning can buy. In this thesis, we aim to provide the network designer with a simple view of the network robustness to traffic matrix changes. We first present the Traffic Load Distribution Plots, or T-Plots, a class of plots illustrating the percentage of traffic matrices that can be serviced as a function of the capacity over-provisioning. For instance, from a simple look at their T-Plots, network designers can guarantee that their network services all admissible traffic matrices, or 99% of permutation traffic matrices, or all traffic matrices with ingress/egress load at most half the maximum. We further show that unfortunately in the general case plotting T-Plots is #P-Complete, i.e. that it is impossible to plot a T-plot in a polynomial time by the noon tools. However, we show that T-Plots can sometimes be closely modeled as Gaussian, thus only using two values (mean and variance) to quantify the robustness of a capacity allocation to traffic matrix changes; and we utilize these Gaussian T-Plots to provide a more robust capacity allocation. Finally, we demonstrate the benefits from using T-Plots by showing results of extensive Monte Carlo simulations in real backbone network.