Title page for ETD etd-08262002-140727

Type of Document

Dissertation

Author

XIN, YUFENG ,

Author's Email Address

yxin@eos.ncsu.edu

URN

etd-08262002-140727

Title

Topology Design of Large-Scale Optical Networks

Degree

PhD

Graduate Program

Operations Research

Advisory Committee

Advisor Name	Title
George N. Rouskas	Committee Chair
Harry G. Perros	Committee Co-Chair
Matt Stallmanne	Committee Member
Yahya Fathi	Committee Member

Keywords

balanced tree
topology design
protection
multicasting
optical networks

Date of Defense

2002-08-15

Availability

unrestricted

Abstract

Optical networks consisting of optical cross-connects(OXCs) arranged in some
arbitrary topology are emerging as an integral part of the Internet
infrastructure. The main functionality of these networks will be to provide
reliable end-to-end lightpath connections to large numbers of electronic label
switched routers (LSRs). We consider two problems that arise in building such
networks. The first problem is related to the topology design of optical networks
that can grow to Internet scales, while the second is related to the light-tree
routing for the provision of optical multicast services.

In the first part of the thesis, we present a set of heuristic algorithms to
address the combined problem of physical topology design (i.e., determine the
number of OXCs required for a given traffic demand and the fiber links among them)
and logical topology design (i.e., determine the routing and wavelength assignment for
the lightpaths among the LSRs). We then extend our study to take
a shared path-based protection scheme into consideration after presenting a
detailed analysis and comparison of different protection strategies.
In order to characterize the performance of our algorithms, we
have developed lower bounds which can be computed efficiently. We present
numerical results for up to 1000 LSRs and for a wide range of system
parameters such as the number of wavelengths per fiber, the number of
transceivers per LSR, and the number of ports per OXC.

In the second part of the thesis, we study the problem of constructing light-trees
under optical layer power budget constraints, with a focus on algorithms
which can guarantee a certain level of quality for the signals received by
the destination nodes. We define a new constrained light-tree routing
problem by introducing a set of constraints on the source-destination
paths to account for the power losses at the optical layer. We
investigate a number of variants of this problem, we characterize their
complexity, and we develop a suite of corresponding routing algorithms.
We find that, in order to
guarantee an adequate signal quality and to scale to large destination
sets, light-trees must be as balanced as possible. Our algorithms
are designed to construct balanced trees which, in addition to having good
performance in terms of
signal quality, they also ensure a certain degree of fairness among
destination nodes.

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