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Optical WDM

Networks

OPTICAL NETWORKS SERIES

Series Editor Biswanath Mukherjee, University of California, Davis

Other books in the series:

TRAFFIC GROOMING IN OPTICAL WDM MESH NETWORKS Keyao Zhu, Hongyue Zhu, Biswanath Mukherjee, ISBN 0-387-25432-3

SURVIVABLE OPTICAL WDM NETWORKS Canhui (Sam) Ou and Biswanath Mukherjee, ISBN 0-387-24498-0

OPTICAL BURST SWITCHED NETWORKS Jason P. Jue and Vinod M. Vokkarane, ISBN 0-387-23756-9

Optical WDM

Networks

Biswanath Mukherjee Department of Computer Science

University of California Davis, CA 95616 U S A .

Email: mukherjee@ cs. ucdavis.edu Tel: +l-530-752-4826 Fax: +1-530-752-4767

Q - Springer

Biswanath Mukherjee Department of Computer Science University of California Davis, CA 95616 U.S.A.

Optical WDM Networks

Series Editor:

Biswanath Mukherjee Department of Computer Science University of California Davis, CA 95616 U.S.A.

Library of Congress Control Number: 2005932754

ISBN 0-387-29055-9 e-ISBN 0-387-29188-1 ISBN 978-0387-29055-3

Printed on acid-free paper.

O 2006 Springer Science+Business Media, Jnc. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, Inc., 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now know or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks and similar terms, even if the are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights.

Printed in the United States of America.

9 8 7 6 5 4 3 2 1 SPIN 1 105 1329

To m y family:

m y parents Dhirendranath and Gita Mukherjee,

m y wife Suprzya Mukherjee,

and m y daughters Bipasha and Suchitra MuMerjee.

Preface

New Materials

Before discussing the book's topic, intended audience, etc., we remark that another book, entitled Optical Communication Networks, was published by the same author in 1997. Eight years is a long time in our fast-moving field. Relative to the old book, a brief outline of the new materials in the new book is provided below, followed by brief descriptions of what has been revamped and what has been deleted.

New Chapters:

Optical Access Networks (Chapter 5)

0 Optical Metro Networks (Chapter 6)

Survivable Optical Networks (Chapter 11)

Light-Trees: Optical Multicasting (Chapter 12)

0 Traffic Grooming in Optical Mesh Networks (Chapters 13 and 14)

0 Impairment-Aware Routing (Chapter 15)

Optical Packet Switching (Chapter 17)

0 Optical Burst Switching (Chapter 18)

Revamped Materials:

Chapter 1 (Introduction) has been enhanced with six new sections to lead the discussion on telecom network overview, business models, traffic models, role of software (and computer science) in optical networks, etc.

Chapter 2 (Enabling Technologies) has been updated, especially with a sig- nificant amount of new switching material.

The materials on single-hop and multihop networks (Chapters 3 and 4) have been condensed, but still retained. Because these topics are quite mature, we see less activity on them in academic research and industry today. But we all know that what seems practical today might not be so tomorrow, and vice versa. Thus, a student of optical networking must be educated on this subject; and a practitioner may find this material to be of easy reference.

0 Network Control and Management (Chapter 16) has undergone very signifi- cant revision.

viii Preface

R,outing and wavelength assignment (RWA) (Chapter 7) has been enhanced with discussions on the routing subproblem and wavelength-assignment heuristics.

0 Chapter 9 has also been enhanced with material on virtual-topology adaptation under dynamic traffic.

a The materials in Chapters 8 (Elements of Virtual-Topology Design) and 10 (Wavelength Conversion) have been retained.

Deleted Materials:

0 The material on optical time-division ~nultiplexing (OTDM) and code-division multiplexing (OCDM) has been deleted; thus, the current book's focus is solely on WDM networks, as reflected in its title.

0 The following chapters have also been deleted: (i) wavelength distributed data interface (WDDI), a multi-wavelength version of FDDI; (ii) all-optical cycle elimination in all-optical networks; and (iii) optimal amplifier placement in all-optical networks.

Interested readers should consult the old book [Mukh97] for these materials.

The Topic

The basic premise of our subject - optical comn~unication networks - is that, as more users start to use our data networks, and as their usage patterns evolve to include more bandwidth-intensive networking applications such as data browsing on the world wide web, Java applications, video conferencing, etc., there emerges an acute need for very high-bandwidth transport network facilities, whose capabilities are much beyond those that current networks (e.g., today's Internet) can provide. Given that a single-mode fiber's potential bandwidth is nearly 50 terabits per second (Tbps), which is nearly four orders of magnitude higher than electronic data rate (of a few tens of Gigabits per second (Gbps) today), every effort should be made to tap into this huge opto-electronic bandwidth mismatch. Wavelength-division multiplexing (WDM) is an approach that can exploit this bandwidth mismatch by requiring that each end-user's equipment operates only a t electronic rate, but multiple WDM channels from different end-users may be multiplexed on the same fiber.

Research and development on optical WDM networks have matured consider- ably over the past decade, with comn~ercial deployment of WDM systems being common. Most such deployments are for WDM optical transmission systems with wavelength channcl counts of 32 to 64. Channel counts as high as 160 are practical today, and expected to increase to 320 per fiber strand. While WDM transmission systems are quite mature, the technologies for optical WDM switching, e.g., optical crossconnects (OXCs) are significantly behind. While a lot of efforts have

Preface ix

been spent on building all-optical (or transparent) switches, the switching that is mature today is based on optical-electronic-optical (OEO) (or opaque) technology. However, besides these hardware platforms, note that intelligence in any network (including an optical network) comes from "software," namely for network control, management, signaling, traffic engineering (or routing), network planning (or optimization), etc. Unfortunately, the role of software - or more generally, the role of computer science and engineering - has been paid little attention in optical network research and development. As a result, the progress in the field of optical networking has not been commensurate with its promise from a decade back.

The above problem needs to be rectified. And everyone with a stake in the field of optical networking (researchers, government funding agencies, telecom network operators, equipment vendors, etc.) needs to realize the important roles which optics, electronics, and software play in building a successful optical network (see Fig. 1.2). These players also need to be mindful of the importance of "cross-layer design" issues involving the physical layer (optics and electronics), the network layer (architecture), and the applications (software) (see Fig. 1.3).

Interest on this topic has been growing to better understand the issues and challenges in designing such networks. It is anticipated that the next generation of the Internet will employ WDM-based optical backbones.

Intended Audience

The intended audience of this book includes researchers, industry practitioners, and graduate students (both as a graduate textbook and for doctoral students' research).

Many electrical engineering, computer engineering, and computer science pro- grams around the world have been offering a graduate course on this topic. That is, research and development on optical communication networks have matured significantly to the extent that some of these principles have moved from the research laboratories to the formal (graduate) classroom setting. While there are several good books that deal mainly with the physical-layer issues of optical communications, e.g., [RaSiOl, DuDF02, Agra041, few books exist on the "networking" side of optical networking. However, these books are also getting outdated by the fast pace of research and development in the field. These observations led me to write this updated textbook on this topic.

I expect that instructors will find the book useful for teaching a graduate course on optical networking. At my home institution, University of California, Davis, I regularly teach a one-quarter graduate course, ECS 259, "Optical Communication Networks," using materials from the book. Actually, I find that the book's contents are longer than what one can cover in a typical quarter-long course (30 hours of lecture) or a semester-long course (45 hours of lecture). Thus, I wish to provide the following helpful guidelines for t,hose who may wish to skip some materials.

Each chapter is typically organized in a stand-alone and modular fashion, so any of them can be skipped, if so desired.

x Preface

Chapters 3 and 4 on single-hop and multihop networks can be skipped.

Courses which are more computer-science oriented may wish to treat enabling technologies (Chapter 2) a t an overview level and skip Chapter 15 on impairment-aware routing.

Some instructor may wish to skip the longer-term research problems on optical packet switching (OPS) and optical burst switching (OBS) (Chapters 17 and 18).

Chapter 12 (Optical Multicasting) may also be skipped by some instructors.

Some instructors may have less interest in metro networks (Chapter 6) and/or access networks (Chapter 5), but I don't recommend skipping Chapter 5.

For teaching short courses (of duration 15 hours +/- 5 hours), I have typically used the following materials: Chapter 1 (Introduction), Chapter 5 (Access), Chapters 7-9 (RWA and virtual-topology design), Chapter 11 (survivability), Chapters 13-14 (Traffic Grooming), and some aspects of Chapter 16 (Network Control and Management).

Since the major developnients in optical con~munication networks have started to capture the imagination of the computing, telecommunications, and opto-electronic industries, I expect that industry professionals will find this book useful as a well- rounded reference. Through my own industry relationships, I find that there exists a large group of people who are experts in physical-layer optics, and who wish to learn more about network architectures, protocols, and the corresponding engineering problems in order to design new state-of-the-art optical networking products. This group of people is also who I had in mind while developing this book.

Organization Principles and Unique Features

Writing a book on optical networking is not easy since such a book has to cover materials that span several disciplines ranging from physics to electrical engineering to computer science to operations research to telecom business models, and also since the field itself is evolving very rapidly. This has been a very challenging exercise.

This book is not intended to cover in any detail the physical-layer aspects of optical communications; readers should consult an appropriate book, e.g., [RaSiOl, DuDF02, AgraO41, for such material. We summarize these "enabling technologies" in a single chapter (Chapter 2). Our treatment of the material in this chapter should allow us to uncover the unique strengths and limitations of the appropriate technologies, and then determine how the characteristics of the physical devices may be exploited in pragmatic network architectures, while compensating for the device limitations or "mismat,chesn .

Preface xi

An important organizing principle that I have attempted to keep in mind while developing this book is that research, development, and education on optical corn- munication networks should allow tight coupling between network architectures and device capabilities. To date, research on optical network architectures has taught us that, without a sound knowledge of device capabilities and limitations, one can produce architectures which may be unrealizable; similarly, research on new optical devices, conducted without the concept of a useful system, can lead to sophisticated technology with limited or no usefulness.

The book is organized into three parts. Part I introduces WDM and its enabling technologies. Part I1 is devoted to WDM local, access, and metro optical network architectures. Part I11 discusses a wide variety of problems in wavelength-routed WDM optical networks for wide-area coverage. The appendices on "where to learn more" and a "Glossary of Important Terms" should also be beneficial to many readers. More details on the book's organization can be found in Section 1.15.

The most unique feature of this book is its timeliness in capturing the state of the art in the fast-moving field of optical WDM networking. Other major salient aspects of the book are its breadth of coverage, depth of malytical treatment, clear identification of recent developn~ents and open problems, an extensive bibliography (535 references), an extensive number of end-of-chapter exercises (a total of 301), an extensive set of illustrations (353 figures, 56 tables), etc.

A solutions manual is currently being developed. Instructors may obtain a copy from the publisher. Please see additional web-based features below.

Web Enhancements

This book is "web-enhanced," i.e., we have (or plan to have) material such as the following available through the web (see author's web address: http://~~etworlcs.cs.ud avis. edu/wrnukh,erje) :

1. table of contents,

2. list of figures,

3. color versions of some figures - some of the figures were drawn originally in color, and the color versions may be more informative than the black-and- white versions appearing in the book,

4. Chapter 1 in its entirety,

5. introductory material for the other chapters,

6. posting of corrections, revisions, updates, etc.,

7. easy mechanism for readers to provide feedback to the author and the publisher, and

8. if and when possible, additional material as deemed useful, e.g., simulations for some single-hop protocols, multicasting, virtual-topology embedding, etc.; allowing animation and remote operation of simulations via parameter selection by the user using Java.

Acknowledgements

Although my name is the only one to appear on the cover, the combination of efforts from a large number of individuals is required to produce a quality book.

First and foremost, I wish to thank Dr. Anpeng Huang for the countless hours of time and effort he spent in getting the book to its current form. Without Dr. Huang's efforts, this book would not have been produced.

Much of the book's material is based on research that I have conducted over the years with my graduate students and research scientists visiting my laboratory, and I would like to acknowledge them as follows: Amitabha Banerjee for optical access networks (Chapter 5); Dhritiman Banerjee for the wavelength-routing material (Chapters 7-8); Mike Borella for the enabling-technologies review (Chapter 2); Wonhong Cho for optical metro networks (Chapter 6); Aysegul Gencata for virtual- topology adaptation (Chapter 9); Anpeng Huang for optical burst switching (Chap- ter 18); Yurong (Grace) Huang for impairment-aware routing (Chapter 15); Jason Iness for multihop networks and wavelength conversion (Chapters 4 and 10); Jason Jue for enabling technologies and single-hop networks (Chapters 2 and 3); Glen Kramer for optical access networks (Chapter 5); Canhui (Sam) Ou for survivability and traffic grooming (Chapters 11 and 14); Byrav Ramarnurthy for wavelength conversion (Chapter 10); S. Ramamurthy for wavelength routing and survivability (Chapters 7 and 11); Laxman Sahasrabuddhe for survivability and optical multicasting (Chapters 11 and 12); Narendra Singhal for optical multicasting (Chap- t.er 12); Srini Tridandapani for channel sharing in multihop networks (Chapter 4); Jian Wang for optical metro networks (Chapter 6); Wushao Wen for survivability (Chapter 11); Shun Yao for optical packet switching (Chapter 17); Hui Zang for wavelength routing and network control &- management (Chapters 7 and 16); Jing Zhang for survivability (Chapter 11); Hongyue Zhu for traffic grooming and metro networks (Chapters 6, 13, and 14); and Keyao Zhu for traffic grooming (Chaptcrs 13 and 14). I would also like to acknowledge Dr. Nasir Ghani for some of the material on optical metro networks (Chapter 6).

A number of additional individuals who I have collaborated with over the years, who have enabled me to better understand the subject matter, and who I would like to acknowledge are the following: Subrata Banerjee, Debasish Datta, Sudhir Dixit, Christoph Gauger, Jon Heritage, Feiling Jia, Sungchang Kim, Behzad Moslehi, Massimo Tornatore, Yinghua Ye, and Ben Yoo.

I would like to thank the following students in my ECS 259 classes (formerly ECS 2891) for developing many of the end-of-chapter problems: Dragos Andrei, Amitabha Banerjee, Steven Cheung, Fred Clarke, Bill Coffman, Anpeng Huang, Yurong (Grace) Huang, Jason Jue, Arijit Mukherjee, Raja hlukhopadhyay, Canhui (Sam) Ou, Vijoy Pandey, Byrav Ramamurthy, S. Ramanlurthy, Smita Rai, Laxnlan Sahasrabuddhe, Suman Sarkar, Huan Song, Lei Song, Feng Wang, Raymond Yip, Hongyue Zhu, and Keyao Zhu. hlurat Azizoglu and Debasish Datta also contributed several problems, while Anpeng Huang, Jason Jue, and Laxman Sahasrabuddhe "organized" these exercises; their efforts are highly appreciated.

Preface xiii

Special thanks are due to Anpeng Huang and Byrav hmarnur thy for the book's "electronic organization," several figure drawings, and answers to my I47$32e ques- tions; and to Ken Victa for developing the graphical user interface (GUI) to visualize and draw the results of our optimization studies.

This book wouldn't have been possible without the support of my research on optical communication networks from several funding agencies as follows: Na- tional Science Foundation (NSF) (Grant Nos. NCR-9205755, NCR-9508239, ECS- 9521249, ANI-9805285, ANI-9986665, ANI-0207864, INT-0323384, ANI-0435525, and ANI-0520190); Defense Advanced Research Projects Agency (DARPA) (Con- tract Nos. DABT63-92-C-0031 and DAAH04-95-1-0487); Air Force Office of Sci- entific Research (AFOSR) (Grant No. 89-0292); Los Ala.mos National Laboratory; Agilent; Alcatel; Bellsouth; Cisco; ETRI; Fujitsu; Nokia; Optivision, Inc.; ON1 Sys- tems; Pacific Telesis; SBC; Sprint; and Universit,~ of California MICRO Program.

Quality control for a book can be ensured through independent technical reviews. In this regard, the following reviewers are deeply appreciated for their time, effort, suggestions for improvement, and feedback on the book's manuscript: Nasir Ghani, Jason Jue, George Rouskas, Smesh Subramanium, Ioannis Tomkos, and Lena Wosinska.

I wish to acknowledge the people at Springer who I interfaced with - Alex Greene and Melissa Guasch - for their assistance during the book's production. The book's camera-ready version was produced by the author with assistance from Dr. Anpeng Huang using the B'QX2e document-processing system.

Finally, I wish to thank my family members for their constant encouragement ancl support: my father Dhirendranath Mukherjee, my mother Gita Mukherjee, my wife Supriya, and my daughters Bipasha and Suchitra. I couldn't have done it without them!

I welcome email from readers who wish to provide any sort of feedback: errors, comments, criticisms, and suggestions for improvements.

Biswanath Mukherjee Davis, California, U.S.A. mukherje0cs.ucdavis.edu

http://networks.cs.ucdavis.edu/~ukherje

Contents

I Introduction 1

1 Optical Networking: Principles and Challenges 3 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Telecom Network Overview . . . . . . . . . . . . . . . . . . . 4 1.3 Telecom Business Models . . . . . . . . . . . . . . . . . . . . 6 1.4 Roles of Three Fields in Optical Networking . . . . . . . . . . 9 1.5 Cross-Layer Design . . . . . . . . . . . . . . . . . . . . . . . . 10 1.6 TE vs . NE . vs . NP . . . . . . . . . . . . . . . . . . . . . . . . 12 1.7 What is an Optical Network? . . . . . . . . . . . . . . . . . . 15 1.8 Optical Networking: Need + Promise = Challenge! . . . . . . 18 1.9 xDM vs . xDMA . . . . . . . . . . . . . . . . . . . . . . . . . 19 1.10 Wavelength-Division Multiplexing (WDM) . . . . . . . . . . . 20

1.10.1 ITU Wavelength Grid . . . . . . . . . . . . . . . . . . 21 1.10.2 A Sample WDM Networking Problem . . . . . . . . . 22

1.11 WDM Networking Evolution . . . . . . . . . . . . . . . . . . 24 1.11.1 Point-to-Point WDM Systems . . . . . . . . . . . . . . 24 1.11.2 Wavelength Add/Drop Multiplexer (WADM) . . . . . 25 1.11.3 Fiber and Wavelength Crossconnects . . . . . . . . . . 25 1.11.4 Development of WDM Networks . . . . . . . . . . . . 29

1.12 WDM Network Constructions . . . . . . . . . . . . . . . . . . 30 1.12.1 Broadcast-and-Select (Local) Optical WDM Network . 30 1.12.2 Wavelength-Routed (Wide-Area) Optical Network . . 32

1.13 WDM Economics . . . . . . . . . . . . . . . . . . . . . . . . . 34 1.14 Sample Research Problems . . . . . . . . . . . . . . . . . . . 35 1.15 Road Map - Organization of the Book . . . . . . . . . . . . . 37

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2 Enabling Technologies: Building Blocks 43 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.2 Optical Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

2.2.1 Optical Transmission in Fiber . . . . . . . . . . . . . . 45 2.2.2 Single-Mode vs . Multimode Fiber . . . . . . . . . . . 48 2.2.3 Attenuation in Fiber . . . . . . . . . . . . . . . . . . . 51

xvi Contents

. . . . . . . . . . . . . . . . . . . . 2.2.4 Dispersion in Fiber 52 . . . . . . . . . . . . . . . . . . 2.2.5 Nonlinearities in Fiber 53 . . . . . . . . . . . . . . . . . . 2.2.6 Optical Fiber Couplers 57

. . . . . . . . . . . . . . . . . . . . . . . 2.3 Optical Transmitters 59 . . . . . . . . . . . . . . . . . . . 2.3.1 How a Laser Works 59

. . . . . . . . . . . . . . . . 2.3.2 Tunable and Fixed Lasers 62 . . . . . . . . . . . . . . . . . . . 2.3.3 Optical Modulation 66

. . . . . . . . . . . . . . . . . . . . . . . . . 2.3.4 Summary 67 . . . . . . . . . . . . . . . . . . 2.4 Optical Receivers and Filters 67

. . . . . . . . . . . . . . . . . . . . . . 2.4.1 Photodetection 68 . . . . . . . . . . . . . . . . . 2.4.2 Tunable Optical Filters 69

. . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Fixed Filters 74 2.4.4 Summary of Optical Filtering Technologies . . . . . . 75

. . . . . . . . . . . . . . . . . . . . 2.4.5 Channel Equalizers 76 . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Optical Amplifiers 77

. . . . . . . . . . . . 2.5.1 Optical Amplifier Characteristics 78 . . . . . . . . . . . . . 2.5.2 Semiconductor Laser Amplifier 79

. . . . . . . . . . . . . . . . . . 2.5.3 Doped-Fiber Amplifier 80 . . . . . . . . . . . . . . . . . . . . . 2.5.4 Raman Amplifier 82

. . . . . . . . . . . . . . . . . . . . . . . . 2.6 Switching Elements 85 2.6.1 Optical Add-Drop Multiplexers (OADM) . . . . . . . 86

. . . . . . . . . . . . . . 2.6.2 Optical Cross-Connect (OXC) 88 . . . . . . . . . . . . . . . . . . . . . 2.6.3 Clos Architecture 92

2.6.4 Micro-Electro Mechanical Systems (MEMS) . . . . . . 93 . . . . . . . . . 2.6.5 Nonreconfigurable Wavelength Router 95

2.6.6 Reconfigurable Wavelength-Routing Switch . . . . . . 99 . . . . . . . . . . . . . . . . . . . . . 2.7 Wavelength Conversion 100

. . . . . . . . . . 2.7.1 Wavelength Conversion Technologies 103 . . . . . 2.8 Designing WDM Networks: Systems Considerations 110

. . . . . . . . . . . . . . . . . . . . . . . . . 2.8.1 Channels 110 . . . . . . . . . . . . . . . . . . 2.8.2 Power Considerations 112

. . . . . . . . . . . . . 2.8.3 All-optical Cycle of Elimination 113 . . . . . . . . . . . . . . . . 2.8.4 Additional Considerations 114

. . . . 2.8.5 Elements of Local-Area WDM Network Design 115 . . . . . . . 2.8.6 WDM Wide-Area Network Design Issues 118

. . . . . . . . . . 2.8.7 WDM Metro Network Design Issues 120 . . . . . . . . . 2.8.8 Optical Access Network Design Issues 121

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 Summary 122

Contents xvii

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

I1 Local. Access. and Metro Networks 131

3 Single-Hop Networks 133 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 3.2 Constructions of Single-Hop Networks . . . . . . . . . . . . . 133 3.3 Characteristics of a Single-Hop System . . . . . . . . . . . . . 137 3.4 Experimental WDM Systems . . . . . . . . . . . . . . . . . . 139

3.4.1 SONATA . . . . . . . . . . . . . . . . . . . . . . . . . 140 3.4.2 LAMBDANET . . . . . . . . . . . . . . . . . . . . . . 141 3.4.3 Rainbow . . . . . . . . . . . . . . . . . . . . . . . . . . 142 3.4.4 Fiber-optic Crossconnect . . . . . . . . . . . . . . . . 143 3.4.5 STARNET . . . . . . . . . . . . . . . . . . . . . . . . 143 3.4.6 Other Experimental WDM Systems . . . . . . . . . . 143

3.5 Other Non-Pretransmission Coordination Protocols . . . . . . 144 3.5.1 Fixed Assignment . . . . . . . . . . . . . . . . . . . . 144 3.5.2 Partial Fixed Assignment Protocols . . . . . . . . . . 146 3.5.3 Random Access Protocols I . . . . . . . . . . . . . . . 147 3.5.4 Random Access Protocols I1 . . . . . . . . . . . . . . . 147 3.5.5 The PAC Optical Network . . . . . . . . . . . . . . . . 148

3.6 Pretransmission Coordination Protocols . . . . . . . . . . . . 150 3.6.1 Partial Random Access Protocols . . . . . . . . . . . . 150 3.6.2 Improved Random Access Protocols . . . . . . . . . . 152 3.6.3 Receiver Collision Avoidance (RCA) Protocol . . . . . 154 3.6.4 Reservation Protocols . . . . . . . . . . . . . . . . . . 156

3.7 Single-Hop Case Study: The Rainbow Protocol . . . . . . . . 158 3.7.1 Rainbow Protocol . . . . . . . . . . . . . . . . . . . . 159 3.7.2 Model of Rainbow . . . . . . . . . . . . . . . . . . . . 160 3.7.3 Analysis of Rainbow . . . . . . . . . . . . . . . . . . . 165 3.7.4 Illustrative Examples of Rainbow . . . . . . . . . . . . 168

3.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

4 Multihop Networks 183 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 4.2 Characteristics of a Multihop System . . . . . . . . . . . . . . 183 4.3 Topological Optimization Studies . . . . . . . . . . . . . . . . 186

xviii Contents

4.3.1 Flow-Based Optimization . . . . . . . . . . . . . . . . 186 4.3.2 Delay-Based Optimization . . . . . . . . . . . . . . . . 187

4.4 Regular Structures . . . . . . . . . . . . . . . . . . . . . . . . 188 4.4.1 ShuffleNet . . . . . . . . . . . . . . . . . . . . . . . . . 188 4.4.2 de Bruijn Graph . . . . . . . . . . . . . . . . . . . . . 191 4.4.3 Torus (Manhattan Street Network) . . . . . . . . . . . 193 4.4.4 Hypercube . . . . . . . . . . . . . . . . . . . . . . . . 194 4.4.5 Other Regular Multihop Topologies . . . . . . . . . . 195

4.5 Multihop Case Study: GEMNET . . . . . . . . . . . . . . . . 196 4.5.1 GEMNET Architecture . . . . . . . . . . . . . . . . . 198 4.5.2 GEMNET Properties . . . . . . . . . . . . . . . . . . 200 4.5.3 Scalability - Adapting the Size of a GEMNET . . . . 207

4.6 Shared-Channel Multihop Systems . . . . . . . . . . . . . . . 209 4.6.1 Channel-Sharing in ShuffleNet . . . . . . . . . . . . . 209 4.6.2 Channel-Sharing in GEMNET . . . . . . . . . . . . . 210


5 Optical Access Networks 223 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

5.1.1 Challenges in Access Networks . . . . . . . . . . . . . 224 5.1.2 Next-Generation Access Networks . . . . . . . . . . . . 225

5.2 Overview of PON Technologies . . . . . . . . . . . . . . . . . 227 5.2.1 Optical Splitters/Couplers . . . . . . . . . . . . . . . . 227 5.2.2 PON Topologies . . . . . . . . . . . . . . . . . . . . . 228 5.2.3 Burst-Mode Transceivers . . . . . . . . . . . . . . . . 228

5.3 Ethernet PON (EPON) Access Network . . . . . . . . . . . . 230 5.3.1 Ethernet Gaining in Prominence . . . . . . . . . . . . 231 5.3.2 Principle of Operation . . . . . . . . . . . . . . . . . . 231 5.3.3 Multi-Point Control Protocol (MPCP) . . . . . . . . . 234 5.3.4 Dynamic Bandwidth Allocation Algorithms . . . . . . 239 5.3.5 Considerations for IP-based Services over EPON . . . 245

5.4 Other Types of PONS . . . . . . . . . . . . . . . . . . . . . . 255 5.4.1 APON/BPON . . . . . . . . . . . . . . . . . . . . . . 255 5.4.2 Generalized naming Procedure PON (GFP-PON) . . 257

5.5 WDM-PON . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257 5.5.1 Need for WDM in PONS . . . . . . . . . . . . . . . . . 257 5.5.2 Arrayed Waveguide Grating (AWG) . . . . . . . . . . 258 5.5.3 WDM-PON Architectures . . . . . . . . . . . . . . . . 259

Contents xix

5.5.4 Scalability of WDM-PON . . . . . . . . . . . . . . . . 264 5.6 Deployment of WDM-PONS . . . . . . . . . . . . . . . . . . . 264

5.6.1 Open Access . . . . . . . . . . . . . . . . . . . . . . . 267 5.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

6 Optical Metro Networks 275 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

6.1.1 Metro WDM Solutions . . . . . . . . . . . . . . . . . . 278 6.1.2 Metro-Edge Solutions . . . . . . . . . . . . . . . . . . 279

6.2 Overview of Traffic Grooming in SONET Ring . . . . . . . . 281 6.2.1 Node Architecture . . . . . . . . . . . . . . . . . . . . 281

. . . . . 6.2.2 Single-Hop Grooming in SONETIWDM Ring 282 6.2.3 Multi-Hop Grooming in SONETIWDM Ring . . . . . 284 6.2.4 Dynamic Grooming in SONETIWDM Ring . . . . . . 287 6.2.5 Grooming in Interconnected SONETIWDM Rings . . 288

6.3 Traffic Grooming in WDM Ring Networks . . . . . . . . . . . 288 6.3.1 Problem Definition . . . . . . . . . . . . . . . . . . . . 288 6.3.2 Solving the ILPs Directly . . . . . . . . . . . . . . . . 292 6.3.3 Heuristics . . . . . . . . . . . . . . . . . . . . . . . . . 293 6.3.4 Illustrative Numerical Results and Comparisons . . . . 297

6.4 Interconnected WDM Ring Networks . . . . . . . . . . . . . . 301 6.4.1 Interconnected Rings . . . . . . . . . . . . . . . . . . . 301 6.4.2 Traffic Grooming in Interconnected Rings . . . . . . . 305 6.4.3 Numerical Results and Analysis . . . . . . . . . . . . . 314

6.5 Packet Communication using Tunable WADM . . . . . . . . 319 6.5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 319 6.5.2 Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 320 6.5.3 Algorithm for Virtual Paths/Wavelength Assignment . 324 6.5.4 Simulation and Illustrative Results . . . . . . . . . . . 330

. . . . . . . . 6.6 Online Connection Provisioning using ROADM 339 . . . . . . . . . . . . . . . . . . . . . . . 6.6.1 Introduction 339

6.6.2 Tuning Constraint . . . . . . . . . . . . . . . . . . . . 340 6.6.3 Problem Statement . . . . . . . . . . . . . . . . . . . . 341

. . . . . . . . . . . . . . . . . . . . . . . . . 6.6.4 Heuristics 343 6.6.5 Illustrative Numerical Excam ples . . . . . . . . . . . . 344


xx Contents

I11 Wavelength-Routed (Wide-Area) Optical Networks 353

7 Routing and Wavelength Assignment 355 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355 7.2 Problem Formulation of RWA . . . . . . . . . . . . . . . . . . 360

7.2.1 Solution Approach . . . . . . . . . . . . . . . . . . . . 360 7.2.2 Problem-Size Reduction . . . . . . . . . . . . . . . . . 361 7.2.3 Randomized Rounding . . . . . . . . . . . . . . . . . . 362 7.2.4 Graph Coloring . . . . . . . . . . . . . . . . . . . . . . 364

7.3 Illustrative Examples from ILP . . . . . . . . . . . . . . . . . 367 . . . . . . . . . 7.3.1 Static Lightpath Establishment (SLE) 368

. . . . . . . 7.3.2 Dynamic Lightpath Establish~nent (DLE) 371 . . . . . . . . . . . . . . . . . . . . . . . 7.4 Routing Subproblem 374

7.4.1 Fixed Routing . . . . . . . . . . . . . . . . . . . . . . 375 7.4.2 Fixed-Alternate Routing . . . . . . . . . . . . . . . . . 375 7.4.3 Adaptive Routing . . . . . . . . . . . . . . . . . . . . 377 7.4.4 Fault-Tolerant Routing . . . . . . . . . . . . . . . . . 378

. . . . . . . 7.5 Wavelength-Assignment Subproblem (Heuristics) 379 . . . . . . . . . 7.6 Illustrative Examples from RWA Subproblem 387

. . . . . . . . 7.7 Simulation Results and Comparison from RWA 390 7.7.1 Comparison among Wavelength-Assignment Heuristics 390

. . . . . . . . 7.7.2 Computational Complexity of Heuristics 394 7.7.3 Comparison of RWA Schemes . . . . . . . . . . . . . . 394


8 Elements of Virtual-Topology Design 401 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401 8.2 System Architecture . . . . . . . . . . . . . . . . . . . . . . . 403

8.2.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . 403 8.2.2 General Problem Statement . . . . . . . . . . . . . . . 405 8.2.3 An Illustrative Example . . . . . . . . . . . . . . . . . 407

8.3 Formulation of the Optimization Problem . . . . . . . . . . . 413 8.3.1 Formulation Equations . . . . . . . . . . . . . . . . . . 413 8.3.2 Explanation of Equations . . . . . . . . . . . . . . . . 416

8.4 Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 8.4.1 Subproblems . . . . . . . . . . . . . . . . . . . . . . . 417 8.4.2 Simulated Annealing . . . . . . . . . . . . . . . . . . . 419 8.4.3 Flow-Deviation Algorithm . . . . . . . . . . . . . . . . 420

Contents xxi

8.5 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . 421 8.5.1 Physical Topology as Virtual Topology (No WDM) . . 423 8.5.2 Multiple Point-to-Point Links (No WRS) . . . . . . . 423 8.5.3 Arbitrary Virtual Topology (Full WDM) . . . . . . . . 424 8.5.4 Comparisons . . . . . . . . . . . . . . . . . . . . . . . 424 8.5.5 Effect of Nodal Degree and Wavelength Requirements 428

8.6 Sum~nary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431

9 Advanced Topics in Virtual-Topology Optimization 433 9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433 9.2 Problem Specification of Linear Program (LP) . . . . . . . . 435

9.2.1 Linear Formulation . . . . . . . . . . . . . . . . . . . . 437 9.2.2 Simplifying Assumptions . . . . . . . . . . . . . . . . . 442

9.3 Heuristic Approaches . . . . . . . . . . . . . . . . . . . . . . . 444 9.4 Network Design: Resource Budgeting and Cost Model . . . . 446

9.4.1 Resource Budgeting . . . . . . . . . . . . . . . . . . . 447 9.4.2 Network-Cost Model . . . . . . . . . . . . . . . . . . . 448

9.5 Virtual-Topology Reconfiguration . . . . . . . . . . . . . . . . 450 9.5.1 Reconfiguration Algorithm . . . . . . . . . . . . . . . 451

9.6 Illustrative Examples . . . . . . . . . . . . . . . . . . . . . . . 452 9.7 Virtual-Topology Adaptation under Dynamic Raffic . . . . . 458

9.7.1 Problem Definition . . . . . . . . . . . . . . . . . . . . 459 9.7.2 Local Optimization for Virtual-Topology Adaptation . 463 9.7.3 Heuristic Adaptation Algorithm for Larger Networks . 471

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.8 Summary 473 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475

10 Wavelength Conversion 479 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479 10.2 Basics of Wavelength Conversion . . . . . . . . . . . . . . . . 482

10.2.1 Wavelength Converters . . . . . . . . . . . . . . . . . 482 10.2.2 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . 483

10.3 Network Design, Control, and Management Issues . . . . . . 485 10.3.1 Network Design . . . . . . . . . . . . . . . . . . . . . . 485 10.3.2 Network Control . . . . . . . . . . . . . . . . . . . . . 486 10.3.3 Network Management . . . . . . . . . . . . . . . . . . 488

10.4 Benefit Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 488 10.4.1 A Probabilistic Approach to WC Benefits Analysis . . 489

xxii Contents

10.4.2 A Review of Benefit-Analysis Studies . . . . . . . . . . 491 10.5 Benefits of Sparse Conversion . . . . . . . . . . . . . . . . . . 494

. . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5.1 Goals 494 10.5.2 Simulator . . . . . . . . . . . . . . . . . . . . . . . . . 495 10.5.3 Single Optical Rings . . . . . . . . . . . . . . . . . . . 496 10.5.4 NSFNET . . . . . . . . . . . . . . . . . . . . . . . . . 497


11 Survivable WDM Networks 507 11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507 11.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511 11.3 Fault Management in SONETISDH . . . . . . . . . . . . . . 512

11.3.1 Unidirectional Path-Switched Ring (UPSR) . . . . . . 513 11.3.2 Bidirectional Line-Switched Ring (BLSR) . . . . . . . 515

11.4 Fault Management in WDM Mesh Networks . . . . . . . . . . 518 11.4.1 Basic Concepts . . . . . . . . . . . . . . . . . . . . . . 518 11.4.2 Ring Cover, Stacked Rings. and Protection Cycles . . 523 11.4.3 Survivable Routing and Wavelength Assignment . . . 527 11.4.4 Maximizing Sharability For Shared-Protection Schemes 536 11.4.5 Dynamic Restoration . . . . . . . . . . . . . . . . . . . 539

11.5 Advanced Topics in Network Survivability . . . . . . . . . . . 541 11.5.1 Service Availability . . . . . . . . . . . . . . . . . . . . 541 11.5.2 Service Reliability and Restorability . . . . . . . . . . 552


12 Light-Tree: Optical Multicasting 561 12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561

12.1.1 Light-Tree for Unicast Traffic: An Illustrative Example 564 12.1.2 Layered-Graph model . . . . . . . . . . . . . . . . . . 565 12.1.3 Steiner Trees . . . . . . . . . . . . . . . . . . . . . . . 567

12.2 Multicast-Capable Switch Architectures . . . . . . . . . . . . 569 12.2.1 Opaque Switch . . . . . . . . . . . . . . . . . . . . . . 569 12.2.2 Transparent Switch . . . . . . . . . . . . . . . . . . . . 570

12.3 Light-Trees for Unicast Traffic . . . . . . . . . . . . . . . . . . 573 12.3.1 General Problem Statement . . . . . . . . . . . . . . . 573 12.3.2 Optimization Problem under Unicast Traffic . . . . . . 574 12.3.3 Illustrative Numerical Examples . . . . . . . . . . . . 580

Contents xxiii

12.4 Light-Trees for Broadcast Traffic . . . . . . . . . . . . . . . . 581 12.4.1 General Problem Statement . . . . . . . . . . . . . . . 581 12.4.2 Optimization Problem under Broadcast Traffic . . . . 582 12.4.3 Illustrative Numerical Example . . . . . . . . . . . . . 584

12.5 Light-Trees for Multicast Traffic . . . . . . . . . . . . . . . . 585 12.5.1 General Problem Statenlent . . . . . . . . . . . . . . 585 12.5.2 Problem Fornlulation for a Network with X Converters 586 12.5.3 Variation of Formulation with no X Converters . . . . 589 12.5.4 Variation of Formulation with Fractional Capacity . . 592 12.5.5 Variation of Formulation with Splitters Constraints . . 593 12.5.6 Illustrative Numerical Examples . . . . . . . . . . . . 596

12.6 Multicast Tree Protection . . . . . . . . . . . . . . . . . . . . 603 12.6.1 Protection Schemes . . . . . . . . . . . . . . . . . . . . 604 12.6.2 General Problem Statement . . . . . . . . . . . . . . . 605 12.6.3 Formulation for a Network without X Continuity . . . 607 12.6.4 Problem Formulation for a Network with X Continuity 610 12.6.5 Illustrative Numerical Examples . . . . . . . . . . . . 612 12.6.6 Other Protection Schemes . . . . . . . . . . . . . . . . 613

12.7 Other Related Issues on Light-Tree Multicasting . . . . . . . 615 12.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618

13 Traffic Grooming 621 13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621

13.1.1 Literature Review . . . . . . . . . . . . . . . . . . . . 623 13.2 Static Traffic Grooming . . . . . . . . . . . . . . . . . . . . . 624

13.2.1 General Problem Statement . . . . . . . . . . . . . . . 626 13.2.2 Node Architecture . . . . . . . . . . . . . . . . . . . . 627 13.2.3 ILP Formulation of the Static Traffic-Grooming . . . . 634 13.2.4 Illustrative Numerical Results From ILP Formulations 641 13.2.5 Heuristic Approach . . . . . . . . . . . . . . . . . . . . 647 13.2.6 Mathematical Formulation Extension . . . . . . . . . 652

13.3 Dynamic Traffic Grooming . . . . . . . . . . . . . . . . . . . . 656 13.3.1 Provisioning Connections in Heterogeneous WDM . . 657 13.3.2 A Generic Provisioning Model . . . . . . . . . . . . . 662 13.3.3 Illustrative Numerical Examples . . . . . . . . . . . . 668


xxiv Contents

14 Advanced Topics in Traffic Grooming 685 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1 Introduction 685

14.2 Hierarchical Switching and Waveband Grooming . . . . . . . 686 . . . . . . . . . . . . . . . . . . . . . . . . 14.2.1 Motivation 686

. . . . . . . . . . . . . . 14.2.2 A Hybrid Node Architecture 687 . . . . . . . . . . . . . 14.2.3 Comparison: Hybrid vs . OEO 693

14.2.4 Research Problems and Challenges . . . . . . . . . . . 694 . . . . . . . . . . . . . . . . . . . . . . 14.3 Virtual Concatenation 696

. . . . . . . . . . . . . . . . . . . . . . . . 14.3.1 Background 696 . . . . . . . . . . . . . . . . . . 14.3.2 Virtual Concatenation 697

. . . . . . . . . . . . 14.3.3 Benefits of Virtual Concatenation 698 . . . . . . . . . . . . . . . . . . . 14.3.4 Related Technologies 703 . . . . . . . . . . . . . . . . . . . 14.4 Survivable Tr&c Grooming 704

. . . . . . . . . . . . . . . . . . . . . . . 14.4.1 Introduction 704 . . . . . . . . . . . . . . . . . . . . 14.4.2 Proposed Schemes 705

14.4.3 Protection-at-Lightpath (PAL) Level . . . . . . . . . . 706 14.4.4 Mixed Protection-at-Connection (MPAC) Level . . . . 708 14.4.5 Separate Protection-at-Connection (SPAC) Level . . . 710

. . . . . . . . . . . . . . . . 14.4.6 A Qualitative Comparison 712 . . . . . . . . . . . . . . 14.4.7 Illustrative Numerical Results 715

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 Summary 717

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exercises 719

15 All-Optical Impairment-Aware Routing 723 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.1 Introduction 723

. . . . . . . . . . . . . . 15.1.1 Transparent Optical Network 724 . . . . . . . . . . . . . . . . 15.1.2 Network Models for RWA 725

15.2 Effects of Transmission Impairments on RWA . . . . . . . . . 725 . . . . . 15.3 Incorporation of Network- and Physical-Layer Effects 726

. . . . . . . . . . . . . . 15.4 Constraints of Physical Impairments 727 . . . . . . . . . . . . . . . . . 15.4.1 PMD Constraint Model 729 . . . . . . . . . . . . . . . . . 15.4.2 OSNR Constraint Model 729

. . . . . . . . . . . . . 15.4.3 Backward-Pumped DRA Model 732 . . . . . . . . . . . . . . . . . . . . . 15.5 Network-Layer Module 736

. . . . . . . . . . 15.6 Characteristics of Impairment-Aware RWA 738 . . . . . . . . . . . . . . . . . . . . . . . 15.7 Other Related Issues 745

15.7.1 Other Problems with Impairment Consideration . . . 745 15.7.2 Security Issues in All-Optical Networks . . . . . . . . 746

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.8 Summary 747

Contents xxv

Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749

16 Network Control and Management 751 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.1 Introduction 751

16.2 Basic Functions of Network Control and Management . . . . 754 . . . . . . . . 16.3 Dynamic Routing and Wavelength Assignment 756

16.3.1 Fixed Routing and Fixed-Alternate-Path Routing . . 756 16.3.2 Adaptive Routing Based on Global Information . . . . 757 16.3.3 Adaptive Routing Based on Neighborhood Infor~nation 758 16.3.4 Adaptive Routing Based on Local Information . . . . 758

. . . . . . . . . . . . . . . . . 16.3.5 Wavelength Assignment 759 . . . . . . . . . . . . . . . 16.4 Signaling and Resource Reservation 759

. . . . . . . . . . . . . . . . . . . 16.4.1 Parallel Reservation 760 . . . . . . . . . . . . . . . . . 16.4.2 Hop-by-Hop Reservation 760

. . . . . . . . . . . 16.5 Two Connection-Management Approaches 762 . . . . . . . . . . . . . . . . . . . . . . . . . 16.5.1 Protocols 762

. . . . . . . . . . . . . . . . . . . . . . . . 16.5.2 Comparisori 763

. . . . . . . . . . . . . . . . . . . . . . . . 16.6 Fault Management 769 . . . . . . . . . . . . . . . . . . 16.6.1 Network Architecture 774 . . . . . . . . . . . . . . . . . . 16.6.2 Protocol Descriptions 775

16.6.3 Illustrative Numerical Examples and Discussion . . . . 784 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16.7 Summary 789 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exercises 791

17 Optical Packet Switching (OPS) 797 17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797 17.2 Optical Packet Switching (OPS) Basics . . . . . . . . . . . . 798

. . . . . . . . . . . . . . . . . . . . . 17.2.1 Slotted Networks 798 . . . . . . . . . . . . . . . . . . . 17.2.2 Unslotted Networks 802 . . . . . . . . . . . . . . . . . . . 17.3 Header and Packet Format 803

17.4 Typical Contention Resolution in OPS Networks . . . . . . . 807 . . . . . . . . . . . . . . . . . . . . . 17.4.1 Optical Buffering 809

. . . . . . . . . . . . . . . . . 17.4.2 Wavelength Conversion 810 . . . . . . . . . . . . . . . . . . . . . 17.4.3 Space Deflection 810

. . . . . . . . . . . . . . . . . . 17.4.4 Combination Schemes 811 17.4.5 Simulation Experiments and Performance Conlparison 812

. . . . . . . . . . . . . 17.5 Hybrid Contention Resolution for OPS 824 . . . . . . . . . . . . . . . . . . . . 17.5.1 Node Architecture 824

. . . . . . . . . . . . . . . . 17.5.2 Simulation Configuration 826

xxvi Contents

. . . . . . . . . . . . . . . . . . . . 17.5.3 Illustrative Results 826 . . . . . . . . . . . . . . . . . . . . . . 17.6 Priority-based Routing 827

. . . . . . 17.6.1 Network Architecture and Routing Policies 827 . . . . . . . . . . . . . . . . . . . . 17.6.2 Illustrative Results 829

. . . . . . . . . . . . . . . . . . 17.7 TCP Performance with OPS 832 . . . . . . . . . . . . . . . . . . . . 17.7.1 Node Architecture 833

. . . 17.7.2 Simulation Configuration and Numerical Results 834 . . . . . . . . . . . . . . . . . . 17.8 Experimental OPS Networks 837

. . . . . . . . . . . . . . . . . . . . . 17.8.1 KEOPS Testbed 837

. . . . . . . . . . . . . . . . . . . . . 17.8.2 DAVID Testbed 838 17.8.3 Advanced Developments in OPS Testbeds . . . . . . . 840

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17.9 Summary 840

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exercises 842

18 Optical Burst Switching (OBS) 845 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.1 Introduction 845

. . . . . . . . . . . . . . . . . 18.2 Burst Assembly and Scheduling 848 . . . . . . . . . . . . . . . . . . . 18.3 Signaling Protocols for OBS 849 . . . . . . . . . . . . . . . . . . . 18.4 Routing Protocols for OBS 853

. . . . . . . . . . . . 18.5 Contention Resolution in OBS Networks 856 . . . . . . . . . . 18.6 Edge and Core Nodes in OBS and Testbeds 858

. . . . . . . . . . . . . . . . . . . . . 18.7 New Challenges in OBS 859 . . . . . . . . . . . . . . . . . . . . . . . . . . 18.8 Trends in OBS 861

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.9 Summary 863

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exercises 864

A Further Reading 867 . . . . . . . . . . . . . . A.l General Resources and Publications 868

. . . . . . . . . . . . . . . . . . . . . . A.2 Enabling Technologies 870 . . . . . . . . . . . . . . . . . . . A.3 Tutorials/Surveys/Reviews 870

. . . . . . . . . . . . . . . . . . . . . . . . . . . A.4 Other Books 871

B Glossary 873

Bibliography 883

Index 941

List of Figures

Telecorn network overview [GersOO] . . . . . . . . . . . . . . . . System: value proposition . . . . . . . . . . . . . . . . . . . . . .

. . . . Optical network architecture: extending our "boundaries" TE vs . NE vs . NP . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . Definition of an optical network Traceroute example . . . . . . . . . . . . . . . . . . . . . . . . The low-attenuation regions of an optical fiber . . . . . . . . . . The ITU wavelength grid with 100-GHz channel spacing [ITU02b] . A four-channel point-to-point WDM transmission system with

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . amplifiers . . . . . . . . . A Wavelength Add/Drop Multiplexer (WADM)

A 4 x 4 passive star . . . . . . . . . . . . . . . . . . . . . . . . . A 4 x 4 passive router (four wavelengths) . . . . . . . . . . . . . A 4 x 4 active switch (four wavelengths) . . . . . . . . . . . . . WDM network evolution . . . . . . . . . . . . . . . . . . . . . . A passive-star-based local optical WDM network . . . . . . . . . A wavelength-routed (wide-area) optical WDM network . . . . . A wavelength-routed WDM network . . . . . . . . . . . . . . . .

The low-attenuation regions of an optical fiber . . . . . . . . . Light traveling via total internal reflection within a fiber . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . Graded-index fiber Numerical aperture of a fiber . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . Single-mode and multimode optical fibers Splitter, combiner. and coupler . . . . . . . . . . . . . . . . . . . A 16 x 16 passive-star coupler . . . . . . . . . . . . . . . . . . . The general structure of a laser . . . . . . . . . . . . . . . . . . . Structure of a semiconductor diode laser . . . . . . . . . . . . . Free spectral rcmge and finesse of a tunable filter capable of tuning to N different channels . . . . . . . . . . . . . . . . . . . Cascading filters with different FSRs . . . . . . . . . . . . . . . .

. . . . . . . . . . . . Structure of a Mach-Zehnder interferometer . . . . . . . . . . . . . . . . . A semiconductor optical amplifier

Erbium-doped fiber amplifier . . . . . . . . . . . . . . . . . . . .

xxviii List of Figures

The gain spectrum of an erbium-doped fiber amplifier with input power = -40 dBm . . . . . . . . . . . . . . . . . . . . . . . . 82 Schematic depicting amplification by stimulated Raman scat- tering in an optical silica fiber . . . . . . . . . . . . . . . . . . . 84

. . . . . . . . . . . . . . . . . . . . Generic OADM architecture 87 Fully-reconfigurable WS and BS OADM architectures [TzZT04] . 88 2 x 2 crossconnect elements in the cross state and bar state . . 89

. . . . . . . . . . . . . Schematic of optical crosspoint elements 90 A 2 x 2 amplifier gate switch . . . . . . . . . . . . . . . . . . . . 92 A 3-stage Clos architecture . . . . . . . . . . . . . . . . . . . . . 93

. . . . . . . . Schematic diagram of a 3D MEMS optical switch 94 . . . . . . . . . . . A 4 x 4 nonreconfigurable wavelength router 96

The arrayed waveguide grating ( AWG) . . . . . . . . . . . . . . 97 A P x P reconfigurable wavelength-routing switch with M wavelengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 An all-optical wavelength-routed network . . . . . . . . . . . . . 101 Wavelength-continuity constraint in a wavelength-routed network . 102 Functionality of a wavelength converter . . . . . . . . . . . . . . 102 An opto-electronic wavelength converter . . . . . . . . . . . . . . 104 A wavelength converter based on nonlinear wave-mixing effects . 105 A wavelength converter using co-propagation based on XGM in an SOA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 An interferonletric wavelength converter based on XPM in SOAs . 107 Conversion using saturable absorption in a laser . . . . . . . . . 108 Experimental setup for demonstrating the polarization-insensitive

. . . . . . 40-Gbps WC based on fiber XPM and optical filtering 109 Broadcast-and-select WDM local optical network with a passive- star coupler network medium . . . . . . . . . . . . . . . . . . . . 116 Lightpath routing in a WDM WAN . . . . . . . . . . . . . . . . 119 A typical WDM metro network . . . . . . . . . . . . . . . . . . . 120 A typical WDM-access network . . . . . . . . . . . . . . . . . . 122 Critical angle in a step index fiber . . . . . . . . . . . . . . . . . 124 Critical angle in a graded index fiber . . . . . . . . . . . . . . . 124

. . . . . . . Two architectures for wavelength convertible routers 128 A WDM WAN constructed using WGRs at each node . . . . . . 130

A broadcast-and-select WDM network . . . . . . . . . . . . . . . 134 An AWG-based single-hop metro network [FaAR05] . . . . . . . 135 SONATA network architecture [BLMNOl] . . . . . . . . . . . . . 141

List of Figures xxix

. . . . . . . . . Architecture of the PAC optical packet network 149 The ALOHAIALOHA protocol . . . . . . . . . . . . . . . . . . . 151 Bimodal throughput characteristics of the slotted-ALOHAIdelayed- ALOHA protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Nonmonotonic delay characteristics of the slotted-ALOHAIdelayed- ALOHA protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 The dynamic time-wavelength division multiple access (DT- WDMA) protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Passive-star topology for Rainbow . . . . . . . . . . . . . . . . . 159

. . . . . . . . . . . . . . . State diagram for the Rainbow model 162 Timing for connection setup . . . . . . . . . . . . . . . . . . . . 164 Throughput vs . arrival rate . . . . . . . . . . . . . . . . . . . . 169 Throughput vs . message size . . . . . . . . . . . . . . . . . . : . 169 Throughput vs . timeout duration with parameters . . . . . . . . 170 Delay vs . throughput for varying message size . . . . . . . . . . 171 Classification of single-hop network architectures [Mukh92a] . . 172

An example four-node multihop network: (a) physical topology, (h) logical topology . . . . . . . . . . . . . . . . . . . . . . . . . 184 A (2. 2) ShuffleNet . . . . . . . . . . . . . . . . . . . . . . . . . . 189 A (2. 3) de Bruijn graph . . . . . . . . . . . . . . . . . . . . . . . 192 A 4 x 6 Manhattan Street Network (MSN) with unidirectional links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 An eight-node binary hypercube . . . . . . . . . . . . . . . . . . 195 A 10-node (2.5. 2) GEMNET . . . . . . . . . . . . . . . . . . . . 197 Bounds and average hop distance for a P = 2. 64-node GEM- NET with different values of K . . . . . . . . . . . . . . . . . . . 206 Growing a (1.6. 2) GEMNET by one node . . . . . . . . . . . . . 208 Twelve-node SC-GEMNETs. along with corresponding timing diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Classification of multihop network architectures [Mukh92b] . . . 214 The (10-node) Peterson graph . . . . . . . . . . . . . . . . . . . 218 A bidirectional ring network . . . . . . . . . . . . . . . . . . . . 218

The comparison between different access mechanisms . . . . . . 225 Fiber-to-the-home (FTTH) deployment scenarios . . . . . . . . . 226 PON topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 Illustration of near-far problem in a TDM PON: a snapshot of

. . . . . . . . . received power levels at OLT from four timeslots 230

xxx List of Figures

Downstream operation in EPON . . . . . . . . . . . . . . . . . . 232 . . . . . . . . . . . . . . . . . . . Upstream operation in EPON 233

Discovery-phase message exchanges . . . . . . . . . . . . . . . . 235 Multi-Point-Control-Protocol (MPCP) REPORT operation . . . 236 Multi-Point-Control-Protocol (MPCP) GATE operation . . . . . 237 Message exchange process of REPORT and GATE handling . . 238 Calculation of round-trip time (RTT) . . . . . . . . . . . . . . . 238 Timing diagram of the limited-service scheme in IPACT . . . . . 241 Average packet delay for different service schemes . . . . . . . . 244 Average cycle times for various service schemes . . . . . . . . . . 245 Slot utilization for various slot sizes . . . . . . . . . . . . . . . . 246 Average packet delay for various classes of traffic as a function

. . . . . . . . . . . . . . . . . . . . of the effective network load 252 Maximum packet delay for various classes of traffic as a function of the effective network load . . . . . . . . . . . . . . . . . . . . 252 APON/BPON frame format . . . . . . . . . . . . . . . . . . . . 256 The periodic routing behavior of an AWG . . . . . . . . . . . . . 259 Composite PON (CPON) [Zirn98] . . . . . . . . . . . . . . . . . 260 LARNET architecture [ZJSD95] . . . . . . . . . . . . . . . . . . 261 RITENET architecture [FIMD94] . . . . . . . . . . . . . . . . . 262 Modulating a multi-wavelength laser source . . . . . . . . . . . . 263 Scalability of a WDM-PON architecture [MMPEOO] . . . . . . . 265 A WDM-PON-based FTTC network deployed as an open-access network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 A PON deploying open access . . . . . . . . . . . . . . . . . . . 267

Sample protocol mappings for metro edge [GhPC02] . . . . . . . 277 Architecture of a WDM ring network node . . . . . . . . . . . . 282 An example of traffic grooming on a Zwavelength network show- ing that different strategies can lead to different network cost . . 283 SONET/WDM ring with/without a hub node . . . . . . . . . . 284 Network design for 2-allowable traffic . . . . . . . . . . . . . . . 287 Non-uniform traffic example . Dots and arrows represent the start and the end of a connection . Circles represent ADMs . . . 298 Statistical result comparison for non-uniform traffic on a bidirectional ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Simplified node architecture of a SONET/WDM ring network . 302 Simplified architectures of different optical crossconnects (OXCs).303

List of Figures xxxi

Three forms of interconnections that can be formed by using strategies 2 and 3 . . . . . . . . . . . . . . . . . . . . . . . . . . 304 Illustrative results of traffic grooming . . . . . . . . . . . . . . . 309

. . . . . . . . . . . . . Interconnected ring used for experiments 315 . . . . . . . . . . . . . . ADM and wavelength usage comparison 316

. . . . . . . . . . An interconnected multi-ring network topology 318 . . . . . . . . . . Average ADM usage for the multi-ring network 318

A comparison of the ring network with tunable transmitters and a fixed receiver at each node and the ring network with a

. . . . . . . . . . . DWADM and a SONET ADM at each node 321 . . . . . . . A DWADM ring network and architecture of node i 322

Data and control channel structure, and control packet format . 329 Results of a simple example with different priority-node selection.331 Packet delays for FiP9+RanS protocols with balanced traffic, A=0.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 Packet delays for RRP+RanS protocols with balanced traffic, A=O.l. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334 Comparison of average packet delays of protocols with balanced traffic, A = 0.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 Delays for RanP+RRS protocols with balanced traffic, A = 1 . . 335 Packet delays with unbalanced traffic, A = 0.1. . . . . . . . . . 336 Throughputs of RanPfRanS protocols with buffer size 32 and balanced traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 Throughputs of RanP+RanS protocols with buffer size 32 and unbalanced traffic . . . . . . . . . . . . . . . . . . . . . . . . . . 339

. . . . . . . . . . . . . . . Switching-based ROADM architecture 341 Tuning-based ROADM architecture . . . . . . . . . . . . . . . . 342 An illustration of tuning constraint . . . . . . . . . . . . . . . . 342 Comparison of heuristics for DWRA subproblem with MCT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tuning 345 Comparison of heuristics for T P subproblem with LHLA for DWRA subproblem . . . . . . . . . . . . . . . . . . . . . . . . . 345 3-node unidirectional network . . . . . . . . . . . . . . . . . . . 350 4-node bidirectional network . . . . . . . . . . . . . . . . . . . . 350

. . . . . . . . . . . . Single-point-connected double-ring network 351

. . . . . . . . . . . . Lightpath routing in an all-optical network 356 A network and a corresponding auxiliary graph . . . . . . . . . . 366

xxxii List of Figures

Effect of nodal degree d' (for K = 2 alternate paths) on wave- . . . . . . . . . . . . . . . . . . . . . . . . . . . . length routing 371

. . . . . . . . Effect of number of connections on link congestion 373 . . . . . . . . Fixed shortest-path route from Node 0 to Node 2 375

Primary (solid) and alternate (dashed) routes from Node 0 to Node 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376 Adaptive route from Node 0 to Node 2 . . . . . . . . . . . . . . 378 Wavelength-usage pattern for a network segment consisting of six fiber links in tandem . . . . . . . . . . . . . . . . . . . . . . . 387

. . . . . . . . . . . . . . . . . . . . . . . . . Si~nulation network 391 Con~parison of Random, FF, LU, MU, Max-Sum, and RCL for single-fiber network with 16 wavelengths . . . . . . . . . . . . . 392 Comparison of Random, FF, LU, MU, MP, LL, Max-Sum, and

. . . . . . . . . . RCL for two-fiber network with 8 wavelengths 392 Comparison of Random, FF, LU. MU. MP. LL. Max-Sum, and RCL for four-fiber network with 4 wavelengths . . . . . . . . . . 393 Cornparison of DRCL, FF (with or not adaptive routing) and RCL for single-fiber network with 16 wavelengths . . . . . . . . 393 Connection requests . . . . . . . . . . . . . . . . . . . . . . . . . 399

NSFNET T l backbone . . . . . . . . . . . . . . . . . . . . . . . 404 Modified physical topology . . . . . . . . . . . . . . . . . . . . . 408 A 16-node hypercube virtual topology embedded on the NSFNET physical topology . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 Details of the Utah (UT) node . . . . . . . . . . . . . . . . . . . 409 The physical topology with embedded wavelengths corresponding to an optimal solution (more than one transceiver at any node can tune to the same wavelength) . . . . . . . . . . . . . . 411 The physical topology with embedded wavelengths corresponding to an optimal solution (all transceiver pairs at any node must be tuned to different wavelengths) . . . . . . . . . . . . . . 411 Delay vs . throughput (scaleup) characteristics with no WDM, i.e., physical topology as virtual topology . . . . . . . . . . . . . 426 Delay vs . throughput (scaleup) characteristics with WDM used on some links, but no WRSs, i.e., multiple point-to-point links are allowed on the physical topology . . . . . . . . . . . . . . . . 426 Delay vs . throughput (scaleup) characteristics with full WDM on some links and a WRS at each node, i.e., arbitrary virtual topologies are allowed . . . . . . . . . . . . . . . . . . . . . . . . 427

List of Figures xxxiii

Delay vs . throughput (scaleup) characteristics for different virtual topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427 Distributions of the number of wavelengths used in each of the 21 fiber links of the NSFNET for the virtual t. opology approach with nodal degree P = 4. 5. and 6 . . . . . . . . . . . . . . . . . 429

NSFNET T l backbone . . . . . . . . . . . . . . . . . . . . . . . 435 Optimal solution for a two-wavelength and a five-wavelength network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 Transport node in the RACE WDM opticd network architecture.448 Average packet hop distance for the optimal solution . . . . . . 453 Average transceiver utilization for the optimal solution . . . . . 454 Average wavelength utilization for the optimal solution . . . . . 454 Comparison of heuristic algorithms for a four-wavelength network.457 Reconfiguration statistics . . . . . . . . . . . . . . . . . . . . . . 457 Traffic nleasuren~ents on a link in the Abilene network . . . . . . 460 Six-node network used in experiments . . . . . . . . . . . . . . . 469 Nurnber of lightpaths in virtual topologies obtained by solving our proposed adaptation MILP and the optimal reconfigliration MILP . . . . . . . . . . . . . . . . . . . . . ... . . . . ... . . . 469 Comparison of the curnulativc nurnber of lightpath changes . . . 470 Example operation of the system for a three-day period . . . . . 472 Physical network topology . . . . . . . . . . . . . . . . . . . . . . 475 Physical network topology . . . . . . . . . . . . . . . . . . . . . . 476

An optical wavelength-routed network . . . . . . . . . . . . . . . 480 Wavelength-continuity constraint in a wavelength-routed network.481 Functionality of a wavelength converter . . . . . . . . . . . . . . 482 A switch with dedicated converters at .tach output port for each wavelength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483 Switches which allow sharing of converters . . . . . . . . . . . . 484 Wavelength conversion for distributed network management . . . 488 Blocking probabilities for different loads in a 10-node optical ring with sparse nodal conversion . . . . . . . . . . . . . . . . . 496 NSFNET with the number of convertible routes shown . . . . . 497 Blocking probabilities in the NSFNET for optirnal and heuristic placement of wavelength converters (30 ERLANG load) . . . . . 499

xxxiv List of Figures

10.10 Comparison of blocking probabilities in the NSFNET when using full conversion and no conversion in the network with the Best-Fit algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . 500

10.11 Percent gain in the NSFNET from using full-conversion at every node as opposed to no conversion in the network . . . . . . . . . 500

10.12 Distribution of the number of wavelength converters utilized at node 2 in the NSFNET (30 ERLANG load) . . . . . . . . . . . . 501

10.13 Network with uniform loading . . . . . . . . . . . . . . . . . . . 505

. . . . . . 11.1 Different types of failures in an optical WDM network 508 11.2 Multiple failures: significance (based on [ToNe94]) . . . . . . . . 510 11.3 An example of automatic protection-switching (APS) protocol . 513 11.4 A unidirectional path-switched ring (UPSR) . . . . . . . . . . . 514

. . . . . . 11.5 A four-fiber bidirectional line-switched ring (BLSRI4) 514 . . . . . . 11.6 A two-fiber bidirectional line-switched ring (BLSRl2) 516

11.7 Protection bandwidth spatial reuse in a BLSR/2 . . . . . . . . . 516 11.8 Link protection vs . path protection . . . . . . . . . . . . . . . . 519 11.9 Examples of 1+1, 1.1, and h4:N path-protection schemes and

the comparison between them . . . . . . . . . . . . . . . . . . . 522 11.10 Different protection and restoration schemes in WDM mesh net-

works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523 11.11 A 10-node network covered by five logical BLSRs . . . . . . . . . 525 11.12 Directed cycles in a 5-node network . . . . . . . . . . . . . . . . 526 11.13 A network with one p-cycle which can protect on-cycle links

and straddling links . . . . . . . . . . . . . . . . . . . . . . . . . 527 11.14 An example where the two-step algorithm fails . . . . . . . . . . 529

. . . . 11.15 An example describing how the one-step algorithm works 530 11.16 An example of backup-sharing optimization . . . . . . . . . . . . 538 11.17 A general backup sharing example . . . . . . . . . . . . . . . . . 547 11.18 State-transition diagram for computing 6;') while assuming backup

always available . . . . . . . . . . . . . . . . . . . . . . . . . . . 548 11.19 State-transition diagram (incomplete) for computing 6t(2) while

assuming backup always available . . . . . . . . . . . . . . . . . 550 11.20 A sample 24-node network topology . . . . . . . . . . . . . . . . 557 11.21 N:l backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558 11.22 Restoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559 11.23 l:N backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559 11.24 Bottleneck cut . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560 11.25 A sample network topology . . . . . . . . . . . . . . . . . . . . . 560

List of Figures xxxv

NSFNET backbone topology. (Link labels correspond to propagation delays.) . . . . . . . . . . . . . . . . . . . . . . . . . . . 563 Virtual links induced by the light-tree consisting of source node

. . . . . . . . . . UT, and destination nodes NE, TX, and IL. 563 Architecture of a wavelength-routed optical network and its layered-graph representation. . . . . . . . . . . . . . . . . . . . 566

. . . . . . A six-node network topology with a light-tree shown. 568 Opaque switch architecture for supporting multicast using elec-

. . . . . . . . . . . . tronic crossconnect and 0-E-0 conversion. 569 Switch architecture for supporting multicasting with all-optical crossconnects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571 Modified switch architecture for supporting multicasting with all-optical crossconnects. . . . . . . . . . . . . . . . . . . . . . 572 Virtual topology of the "broadcast layer", which consists of 21 transmitters and 35 receivers. Each node broadcasts its information over a sp,uming tree on the "broadcast layer". . . . . . 584 Optirnal routing of the group of five multicast sessions with full-range wavelength converters. . . . . . . . . . . . . . . . . . 597 Optimal routing and wavelength assignment of the group of five multicast sessions with no wavelength conversion. . . . . . . . . 597 A typical 15-node telco network topology with bidirectional links. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599 Optimal routing and wavelength assignment of the group of seven multicast sessions with full wavelength-conversion. . . . . 600 Optimal routing and wavelength assignment of the group of

. . . . seven multicast sessions with no wavelength conversion. 601 Optimal routing and wavelength assignment of the group of six fractional-capacity multicast sessions with full wavelength conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602 Fiber cuts along a light-tree from a source node to a set of destination nodes dl, d2, and ds. . . . . . . . . . . . . . . . . . 606 Optimal RWA of a group of eight ~nulticast sessions in absence of A-continuity constraint. . . . . . . . . . . . . . . . . . . . . . 614 Optimal RWA of a group of eight multicast sessions in presence of )\-continuity constraint. . . . . . . . . . . . . . . . . . . . . . 614 Using shared segment-disjoint approach to protect a multicast

. . . . . session where directed-link-disjoint tree approach fails. 616

xxxvi List of Figures

12.19 Using optimal path-pair approach to protect a multicast session . . . . . . . . . . where directed-link-disjoint tree approach fails 616

. . . . . . . . . . . . . . 13.1 Illustrative example of traffic grooming 625 13.2 Node architecture 1: IP over WDM . . . . . . . . . . . . . . . . 628

. . . . . . . . . . . . . 13.3 Node architecture 2: SONET over WDM 629 13.4 A multi-hop partial-grooming OXC . . . . . . . . . . . . . . . . 631

. . . . . . . . . 13.5 Sample source-node grooming OXC architecture 633 13.6 Examples of source-node grooming schemes . . . . . . . . . . . . 634 13.7 Illustrative example of a fiber link, a lightpath, and a connection

request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636 13.8 Physical network topology . . . . . . . . . . . . . . . . . . . . . . 642 13.9 Network throughput vs . number of wavelengths for the network

topology in Fig . 13.8(b) with 10 tunable transceivers at each node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652

13.10 Network throughput vs . number of tunable transceivers for the network topology in Fig . 13.8(b) with 10 wavelengths on each fiber link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653

13.11 Network throughput vs . number of wavelengths (size of fixed transceiver array) for the network topology in Fig . 13.8(b) with 12 tunable transceivers at each node . . . . . . . . . . . . . . . . 654

13.12 Network state for a simple three-node network and the corresponding auxiliary graph . . . . . . . . . . . . . . . . . . . . . . 663

13.13 Different grooming OXCs and their representations in the auxiliary graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666

. . . . 13.14 Two alternative routes for a new connection request (1,2) 667 13.15 A 19-node network . . . . . . . . . . . . . . . . . . . . . . . . . . 669 13.16 Percentage of blocked traffic when Tx = 32 . . . . . . . . . . . . 670 13.17 Percentage of blocked traffic when T x = 40 . . . . . . . . . . . . 670 13.18 Performance of AGP when T x = 32 . . . . . . . . . . . . . . . . 671 13.19 Performance of AGP when T x = 40 . . . . . . . . . . . . . . . . 671 13.20 Sample network topology with 5 grooming nodes . . . . . . . . . 672

. 13.21 Traffic blocking ratio vs offered load . . . . . . . . . . . . . . . . 674 . . . . . . . . 13.22 Normalized resource-efficiency ratio vs offered load 675

. . . . . . . . . . 13.23 Connection blocking probability vs offered load 676 13.24 Graph representing network topology . . . . . . . . . . . . . . . 679 13.25 The optical network . . . . . . . . . . . . . . . . . . . . . . . . . 680 13.26 The network topology . . . . . . . . . . . . . . . . . . . . . . . . 681 13.27 The network topology . . . . . . . . . . . . . . . . . . . . . . . . 681

List of Figures xxxvii

Another network topology . . . . . . . . . . . . . . . . . . . . . . 682

Different types of node architectures [GersOO] . . . . . . . . . . . 688 Comparison between switching types of OEO and 000 . . . . . 689 Architecture of proposed optical switch incorporating all-optical

. . . . . . . . waveband switching and OEO grooming switching 692 Comparison between hybrid hierarchical switch and OEO full- grooming switch . . . . . . . . . . . . . . . . . . . . . . . . . . . 695 An example of using VC to support different network services . 698 An overview of VC-enabled multi-service optical network . . . . 698 A 24-node example network topology . . . . . . . . . . . . . . . 700 Illustrative numerical results . . . . . . . . . . . . . . . . . . . . 702 GFP mapping to SONET/SDH . . . . . . . . . . . . . . . . . . 704 A simplified partial-grooming-node architecture . . . . . . . . . 706 Example: initial network configuration . . . . . . . . . . . . . . 707 PAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708 MPAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709 SPAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 Bandwidth-blocking ratio versus network offered load . . . . . . 716

Three schemes for RWA comparisons . . . . . . . . . . . . . . . 725 Integrated model of impairment-aware RWA algorithms . . . . . 728 A sample of a lightpath architecture . . . . . . . . . . . . . . . . 730 Architecture of a wavelength-routing node (WRN) . . . . . . . . 730 A sample mesh network with fiber lengths (in km) marked on each link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740 Connection blocking probability vs . network offered load (in Erlangs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 742 Comparison of connection-blocking probability between algorithms employing in-line EDFA . . . . . . . . . . . . . . . . . . . 743 Average number of trials for signal-quality estimation per call . 744 Effect of channel bit rate on algorithms in a realistic network . . 745

NSFNET: a nation-wide backbone network . . . . . . . . . . . . 764 Connection set-up delay versus load for NSFNET and 8 wavelengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766 Blocking probability versus load for NSFNET and 8 wavelengths . 767 Stabilizing delay versus load for NSFNET and 8 wavelengths . . 768 Network utilization versus load for NSFNET and 8 wavelengths . 768

xxxviii List of Figures

Different protection and restoration schemes . . . . . . . . . . . 772 . . . . . . . Architecture of a wavelength-routed WDM network 775

Layered-graph model of the wavelength-routed WDM network with three wavelengths . . . . . . . . . . . . . . . . . . . . . . . 776 An example of the downstream node of a failed link notifying the connection source . . . . . . . . . . . . . . . . . . . . . . . . 779 Saniple network . . . . . . . . . . . . . . . . . . . . . . . . . . . 785 Blocking probability versus load for dedicated-path 1:l and 1+1 protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787 Blocking probability versus load for shared-path protection, FF for backup-path wavelength assignment . . . . . . . . . . . . . . 787 Blocking probability versus load for shared-path protection. MSF

. . . . . . . . . and FF for backup-path wavelength assignment 788 Blocking probability versus load for shared-path protection. LF for backup-path wavelength assignment . . . . . . . . . . . . . . 788 Blocking probability versus load for shared-path protection. MSF

. . . . . . . . . and FF for backup-path wavelength assignment 789 Network topology . . . . . . . . . . . . . . . . . . . . . . . . . . 791 Another Network topology . . . . . . . . . . . . . . . . . . . . . 792 Disjoint primary and backup paths . . . . . . . . . . . . . . . . . 793 A sample network for protection switching . . . . . . . . . . . . 794 Availability of a connection carried over disjoint primary and backup paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794

. . . . . . . . A generic node architecture of the slotted network 799 Functional block diagram for synchronization of packets . . . . . 800

. . . . . . . A schen~e for input synchronization stage in a node 801 . . . . . . . A generic node architecture of the unslotted network 803

. . . . . . . . . Power spectrum of the laser modulation current 804 Header retrieval in SCM . . . . . . . . . . . . . . . . . . . . . . . 805 Packet forrnat in KEOPS project . . . . . . . . . . . . . . . . . . 806 Node architectures for different contention-resolution schemes . . 809 An example mesh network topology . . . . . . . . . . . . . . . . 812

. . . . Probability distribution function (PDF) of IP packet sizes 815 Performance comparison of the basic schemes - baseline and wavelength conversion . . . . . . . . . . . . . . . . . . . . . . . . 817 Performance co~nparison of the basic schernes - baseline, optical buffering, and deflection . . . . . . . . . . . . . . . . . . . . . . . 819

. . . . . . . Performance comparison of the combination schemes 822

List of Figures xxxix

Performance comparison of limited wavelength conversion . . . . 823 Client interface of OPS networks . . . . . . . . . . . . . . . . . . 824 Architecture of =an optical packet switch incorporating hybrid contention resolution . . . . . . . . . . . . . . . . . . . . . . . . 825

. . . . . . . . . . . Comparison of different simulation scenarios 827 Network topology under study . . . . . . . . . . . . . . . . . . . 828 The architectures of nodes . . . . . . . . . . . . . . . . . . . . . 828 Performance comparison of priority-based routing (10%-30%- 60% priority distribution) . . . . . . . . . . . . . . . . . . . . . . 830 Performcance comparison of priority-based routing (30%-30%-

. . . . . . . . . . . . . . . . . . . . . . 40% priority distribution) 832 Proposed node architecture . . . . . . . . . . . . . . . . . . . . . 834 Network topology for TCP experiment . . . . . . . . . . . . . . 835 Conlparison of TFTP . . . . . . . . . . . . . . . . . . . . . . . . . 836 Broadcast-and-select switch proposed in the KEOPS project . . 837 '

The architecture in the DAVID project . . . . . . . . . . . . . . 839

An OBS network . . . . . . . . . . . . . . . . . . . . . . . . . . . 847 Comparison between OBS and OPS [QiChOS] . . . . . . . . . . . 847 Just-In-Time (JIT) switching . . . . . . . . . . . . . . . . . . . . 850 Just-Enough-Time (JET) switching . . . . . . . . . . . . . . . . 851 Time-Label (TL) switching . . . . . . . . . . . . . . . . . . . . . 852 Time-Space Label-Switching Protocol . . . . . . . . . . . . . . . 855 Three-dimensional Label-Switching Protocol . . . . . . . . . . . 855 Architecture of a core node in OBS . . . . . . . . . . . . . . . . 859 Optical Self-similar Cluster Switching (OSCS) . . . . . . . . . . 860 Trend of optical switching technologies . . . . . . . . . . . . . . 862

List of Tables

Tunable optical transmitters and their associated tuning ranges and times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Tunable optical filters <and their associated tuning ranges and times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Summary of optical filtering technologies [TzZT04] . . . . . . . . 75 Characteristics of OFAs and SOAs . . . . . . . . . . . . . . . . . 78 Amplifier characteristics . . . . . . . . . . . . . . . . . . . . . . . 82

. . . . . . . . . . . . . . . . Requirements for EDFA applications 112

Comparison of GEMNET (GN). ShuffleNet (SN) and de Bruijn (DB) graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Sequence of requests from ONUS . . . . . . . . . . . . . . . . . 271

Cornparison of previous work on traffic groorning on ring networks.286 Computation time (in seconds) and optimal solution for the single-hop case . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Results from different solutions to the traffic-grooming problem . 294 Comparison of single-hop and multihop approaches . . . . . . . 301 Control packet with destination node information of each node . 329

. . . . . . . . . . . . . . . A source and destination node matrix 330 Control packet with assigned channel number of a simple example . 330 Cornparison of throughputs of protocols with balanced and unbalanced traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

Sample numerical results for static lightpath establishment (SLE) on a 100-node random network . . . . . . . . . . . . . . . . . . . 370 Sample numerical results for dynamic lightpath establishment (DLE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 The calculation in M C . . . . . . . . . . . . . . . . . . . . . . . 388 The calculation in RCL . . . . . . . . . . . . . . . . . . . . . . . 388 The calculation in DRCL . . . . . . . . . . . . . . . . . . . . . . 389 Summary of RWA schemes . . . . . . . . . . . . . . . . . . . . . 395

8.1 Traffic matrix (in bytes per 15-minute interval) . . . . . . . . . . 422

xlii List of Tables

Summary of experimental results . . . . . . . . . . . . . . . . . . 423 Virtual topology for nodal degree P = 4 and best scaleup (106) . 425 Traffic scaleups for different nodal degrees . . . . . . . . . . . . . 428

Cost of upgrading the NSFNET using WDM . . . . . . . . . . . 450 Average packet hop distance for different virtual-topology establishment algorithms . . . . . . . . . . . . . . . . . . . . . . . 458

Failure rates and repair times (Bellcore Statistics) . . . . . . . . 508 Comparison of related work on dynamic shared protections . . . 521

Average packet hop distance for a lightpath-based virtual topology and a light-tree-based virtual topology . . . . . . . . . . . . 581 The number of transceivers required by a lightpath-based virtual topology and a light-tree-based virtual topology for different traffic matrices . . . . . . . . . . . . . . . . . . . . . . . . . . 582 Optimal routing and wavelength assignment of multicast sessions in a network with and without wavelength converters . . . 596 Optimal routing and wavelength assignment of multicast sessions carrying traffic at a fraction of the channel capacity . . . . 598 Aggregate cost of optimally setting up the group of five multicast sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599 Cost incurred when optimally setting up a group of seven multicast sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603 A group of 15 multicast sessions . . . . . . . . . . . . . . . . . . 604

Traffic matrix of OC-1 connection requests . . . . . . . . . . . . 644 Traffic matrix of OC-3 connection requests . . . . . . . . . . . . 644 Traffic matrix of OC-12 connection requests . . . . . . . . . . . . 644 Throughput and number of lightpaths established (total traffic demand is OC.988) . . . . . . . . . . . . . . . . . . . . . . . . . 645 Results: transceiver utilization (multi-hop case) . . . . . . . . . 645 Results: wavelength utilization (multi-hop case) . . . . . . . . . 646 Result: virtual topology and lightpath utilization (multi-hop case with T=5 and W=3) . . . . . . . . . . . . . . . . . . . . . . 647 Throughput results comparison between ILP and heuristic algorithms (total traffic demand is OC.988) . . . . . . . . . . . . . 651 Results of comparison between revenue model and network throughput model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655

List of Tables xliii

Average utilization of wavelength-links and transceivers when W=16 and L=300 Erlangs . . . . . . . . . . . . . . . . . . . . . 669

. . . . . . . . . . . . . . . . Traffic pattern 11: ten service classes 700

System parameter used in the models . . . . . . . . . . . . . . . 733

CST at Node 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777

Deflection table of node 7 . . . . . . . . . . . . . . . . . . . . . . 813 . . . . . . . . . . . . . . Network parameters used in simulation 816

Comparison of upper-bound average offered transmitter load with packet-loss rate of 0.01. . . . . . . . . . . . . . . . . . . . 821

Comparison between various switching methods . . . . . . . . . 846 Comparison between the three signaling protocols in OBS . . . . 853 Comparison of contention-resolution schemes in OBS . . . . . . 858

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