iii

PERFORMANCE STUDY OF PACKET-OPTICAL TRANSPORT

NETWORK PROTOCOLS

AYAD TARIQ MOHAMMED AL-MASHHADANI

A project report submitted in partial fulfilment of the

requirements for the award of the degree of

Master of Engineering (Electronic and Telecommunication)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

JUNE 2016

ii

Especially dedicated to my parents, for their infinite

support and care.

iii

ACKNOWLEDGEMENT

In the name of ALLAH, the most beneficent and the most merciful, I would like

to express my grateful to Him for giving me the strength and the ability to complete this

project report with good standards. Blessings be upon him Prophet Muhammad S.A.W.

Many individuals have profoundly influenced me during this thesis, and it is a pleasure to

acknowledge their guidance and support.

First of all, I would like to generously thank my parents whom I’m always proud

of for their countless encouragements toward perseverance, success, and triumph

throughout my lifetime, to only thrive and stay blissful. I also wish to record my

appreciation to my supervisor Dr. Nadiatulhuda Binti Zulkifli for providing me with

suggestions, comments and resolving bunch of my difficulties in this report.

Last but not least, I want to express my appreciation to my fellow friends who

helped me a lot in this project. Needless to say without all the above help and support, the

writing and production of this project report would not have been possible.

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ABSTRACT

This research is carried out in the field of Optical Transport Network (OTN), in

particular, to investigate the performance of a new protocol called Packet Optical Network

that was introduced as a successor to the legacy Synchronous Digital

Hierarchy/Synchronous optical networking (SDH/SONET). The migration to IP/Ethernet

application globally is forcing enterprises to address two major (Wide Area Network)

WAN issues: converging Time Division Multiplexing (TDM) and packet networks to

reduce expenses, and improving network and service management to support delay-

sensitive, bandwidth-intensive applications. Optical Transport Network - ITU G.709 is a

global standard to address these challenges by eliminating unnecessary layer, IP straight

over optic without being encapsulated in ATM/SDH frames, and eventually reduce

Optical-Electronic-Optical (OEO) conversion. The International Telecommunication

Union Telecommunication Standardization Sector ITU-T defines an OTN as a set of

Optical Network Elements (ONE) connected by optical fiber links, able to provide

functionality of transport, multiplexing, switching, management, supervision, and

survivability of optical channels carrying client signals. Packet Optical Network or often

called Optical Channel Digital Wrapper added more functionalities to the legacy

SONET/SDH such as the inclusion of stronger FEC, switching scalability, Transparency,

and different frame rates. The Optical Channel Payload Envelope (OCh PE) can carry any

type of data: SONET/SDH, GbE, 10GbE, ATM, IP, and so on. The objective of this

research is to model an Optical Transport Network in the OMNeT++ simulation

environment and OptiSystem Software, where the performance of Packet Optical Network

protocols is compared with the legacy system in terms of delay and error correction

capability. Simulation conducted in the metro/core optical network environment shows

that the optical network performances in delay and error performance are improved when

using the Packet optical network protocol, up to 30% decrease in delay can be achieved

v

and longer distances can be reached by employing the new more powerful Forward Error

Correction of the Digital Wrapper G.709.

vi

ABSTRAK

Kajian ini dijalankan dalam bidang optik Transport Network (OTN), khususnya,

untuk menyiasat prestasi protokol baru yang dipanggil paket rangkaian optik yang

diperkenalkan sebagai pengganti kepada legasi Synchronous Digital Hierarchy rangkaian

optik / segerak (SDH / SONET). Penghijrahan ke application / Ethernet IP global

memaksa perusahaan untuk menangani dua utama (Wide Area Network) WAN isu:

menumpu Bahagian Masa Multiplexing (TDM) dan rangkaian paket untuk mengurangkan

perbelanjaan dan meningkatkan rangkaian dan pengurusan perkhidmatan untuk

menyokong kelewatan sensitif, jalur lebar aplikasi -intensive. Optical Transport Network

- ITU G.709 adalah standard global untuk menangani cabaran-cabaran ini dengan

menghapuskan lapisan yang tidak perlu, IP lurus sepanjang optik tanpa terkandung dalam

bingkai ATM / SDH, dan akhirnya mengurangkan (OEO) penukaran-Electronic-optik

optik. Packet Network optik atau sering dipanggil Optical Channel Digital Wrapper

menambah lebih banyak fungsi kepada warisan SONET / SDH seperti kemasukan FEC

kuat, beralih berskala, ketelusan dan kadar bingkai yang berbeza. The Optical Channel

muatan Sampul Surat (Och PE) boleh membawa apa-apa jenis data: SONET / SDH, GbE,

10GbE, ATM, IP, dan sebagainya. Objektif kajian ini adalah untuk model yang

Pengangkutan Rangkaian optik dalam ++ persekitaran OMNeT simulasi dan OptiSystem

Software, jika pelaksanaan paket protokol rangkaian optik dibandingkan dengan sistem

legasi dari segi kelewatan dan kesilapan keupayaan pembetulan. Simulasi dijalankan

dalam persekitaran rangkaian metro / teras optik menunjukkan bahawa persembahan

rangkaian optik kelewatan dan kesilapan prestasi adalah lebih baik apabila menggunakan

protokol rangkaian optik paket, sehingga 30% dalam kelewatan boleh dicapai dan jarak

yang jauh boleh dicapai dengan menggunakan yang baru yang lebih kuat Forward Ralat

Pembetulan Digital Wrapper G.709.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION i

DEDICATION ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF ABBREVIATIONS xii

LIST OF APPENDICES xv

1 INTRODUCTION 1

1.1 Background 1

1.2 Problem statement 2

1.3 Objectives of Research 3

1.4 Scope of Research 3

2 LITERATURE REVIEW 5

2.1 Overview 5

2.2 Evolution of Optical Transport Networks 5

2.2.1 Plesiochronous Digital Hierarchy 5

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2.2.2 Synchronous Optical Network and Synchronous

Digital Hierarchy 7

2.2.3 Optical Transport Network G.709 11

2.3 Previous performance studies 14

2.3.1 OTN Switching 14

2.3.2 Packet Loss 18

2.3.3 Bandwidth Utilization 19

3 REASEARCH METHODOLOGY 20

3.1 Overview 20

3.2 OMNeT++ Simulation 22

3.2.1 OMNeT++ Software 22

3.2.2 OMNeT++ Environment 23

3.2.3 OMNeT++ Design 25

3.2.4 OTN and SONET Modelling 28

3.3 Optisystem Simulation 28

3.3.1 Optisystem Software 29

3.3.2 Optisystem Design 30

4 RESULTS AND DISCUSSION 32

4.1 Overview 32

4.2 Delay Results and Analysis (OMNeT) 32

4.3 Error Correction Capability (OptiSystem) 35

5 CONCLUSION AND FUTURE WORK 38

5.1 Conclusion 38

5.2 Future work 39

REFERENCES 40

Appendix A 42

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LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 European standard of PDH 6

2.2 North American standard of PDH 7

2.3 Standard Optical Interfaces for SONET and SDH 9

3.1 Packet Size Distribution of IP4 traffic 27

3.2 Parameters values for 1 and 2.5 Gbps system 30

3.3 Parameters values for 10 and 40 Gbps system 31

4.1 Sources of Latency in Optical Networks and their

Approximate Values 32

x

LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 OTN and SDH/SONET Transport Network layering 2

2.1 Basic STM-N frame structure 8

2.2 Simplification of SDH/SONET concept 10

2.3 The three Network Layers of SDH/SONET 10

2.4 Basic OTN Transport structure 12

2.5 Simplified OTN network 13

2.6 IP simulation model. A three-node packet switching scenario 15

2.7 OTN simulation model. A three-node OTN switching scenario;

the OTN simulator models the impact of using OTN switches

combined with IP routers in the core network 15

2.8 Reconfigurable OTN simulation model. Capable of

reconfiguring link capacities according to the traffic

arrival intensity to the two output buffers 15

2.9 Average packet delay with increasing traffic load

– IP vs. OTN vs. R-OTN simulator. Blue line (top):

OTN, Green line (middle): R-OTN, Purple line (bottom): IP 16

2.10 Average packet loss with increasing traffic load

– IP vs. OTN vs. R-OTN simulator. Blue line (top): OTN,

Purple line (middle): IP, Green line (bottom): R-OTN 17

2.11 packet loss rate due to bit-errors as function of BER

with total packet/burst length L and number of hops H as

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parameters. The plot derived from a proposed

mathematical modal 18

2.12 Reduction in Wavelength Consumption Using OTN Switching 19

3.1 Research Methodology Flow Chart 21

3.2 OMNeT++ Introduction photo 22

3.3 building and Running Simulation in OMNeT 24

3.4 Screenshot of the software screens and environment 25

3.5 3-node Network designed in OMNeT 25

3.6 Packet Size Distribution of IP4 Traffic 26

3.7 OptiSystem environment 29

3.8 1 and 2.5 Gbps design in OptiSystem 30

3.9 10 and 40 Gbps design in OptiSystem 31

4.1 Total delay across different Optical Carrier Levels 34

4.2 Transmission delay across different Optical Carrier Levels 35

4.3 BER vs. Q Factor 36

4.4 BER performance for 1 Gbps and 2.5 Gbps system 36

4.5 BER performance for 10 Gbps and 40 Gbps system 37

xii

LIST OF ABBREVIATIONS

ADM - Add Drop Multiplexor

ATM - Asynchronous Transfer Mode

AU - Administrative Unit

BCH - Bose-Chaudhuri-Hochquenghem

BER - Bit Error Rate

DCF - Dispersion Compensating Fiber

DCM - Dispersion Compensating Module

DEMUX - Demultiplexer

DWDM - Dense Wavelength Division Multiplexing

EDFA - Erbium-Doped Fiber Amplifier

ETSI - European Telecommunications Standards Institute

FAS - Frame Alignment Signal

FEC - Forward Error Correction

GFEC - Generic Forward Error Correction

GUI - Graphical User Interface

IDE - Integrated Development Environment

IEEE - Institute of Electrical and Electronics Engineers

INI - Initialization

IP - Internet Protocol

ITU - International Telecommunication Union

LTE - Line Terminating Equipment

MSG - Message

MUX - Multiplexer

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NED - Network Description language

OAM&P - Operations, Administration, Management and Provisioning

OC - Optical Carrier

OCH - Optical Channel

ODU - Optical Data Unit

OEO - Optical-Electrical-Optical

OMNeT++ - Objective Modular Network Testbed in C++

OMS - Optical Multiplex Section

ONE - Optical Network Element

OPU - Optical Payload Unit

OSC - Optical Supervisory Channel

OTH - Optical Transport Hierarchy

OTN - Optical Transport Network

OTS - Optical Transmission Section

OTU - Optical Transport Unit

PDH - Plesiochronous Digital Hierarchy

PLR - Packet Loss Rate

QoS - Quality of Service

ROADM - Reconfigurable Optical Add/Drop Multiplexor

R-OTN - Reconfigurable OTN

RS - Reed Solomon

SDH - Synchronous Digital Hierarchy

SNR - Signal to Noise Ratio

SONET - Synchronous Optical Network

STE - Section Terminating Equipment

STM - Synchronous Transport Module

STS - Synchronous Transport Signal

TDM - Time Division Multiplexing

TU - Transmission Unit

TUG - Transmission Unit Group

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VC - Virtual Container

VLSI - Very Large Scale Integrated Circuits

WAN - Wide Area Network

WDM - Wavelength Division Multiplexing

xv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A OMNeT++ code 30

CHAPTER 1

INTRODUCTION

1.1 Background

Global IP traffic is growing rapidly, statistics show that it has increased more

than five times in the past five years, and will increase almost three times over the next

5 years [1]. This explosion of digital traffic is mainly caused by streaming services,

cloud computing, mobile applications and social networks in addition to other

applications, and it is driving the Telecommunication industry and service providers

to evolve rapidly.

Previously, most network traffic was occupied by voice calls, in which traffic

was carried out over connection oriented network in a predictable connection between

two end points. The infrastructure was built by copper cables. But as the overall

network load is increasing, optical networks replaced the previous copper-based

networks, and became the dominant in transport infrastructure for data. This made it

possible for the service providers to handle the rapid growing traffic, as it allows for

data rates of 40 Gbps and above per wavelength. This powerful transport network was

also utilized by using packet switched data deploying a variety of protocols instead of

the traditional circuit-switched method of transferring data, as it was shown that it is

the best option for intermittent low traffic loads from an energy-and-cost point of view

[2].

2

The International Telecommunication Union - Telecommunication

Standardization Sector (ITU-T) Recommendation G.709 is commonly called Optical

Transport Network (OTN) or Digital Wrapper Technology. It was designed and

employed for point-to-point links where the enhanced Forward Error Correction (FEC)

capability allows longer spans or higher data rates [3]. However, it is now used as a

new network layer and considered as the successor of SDH/SONET, because it was

designed with future bandwidth and protocol requirements while preserving the

advantages of SDH/SONET. It is employed as a transport protocol for a transparent,

scalable and cost-effective network where current standards like Ethernet and

SDH/SONET can be the client signals.

IP / Ethernet

ATM IP / Ethernet / ATM / SONET /

SDH

SDH / SONET OTN

Fiber (Single Wavelength) Fiber (DWDM)

Figure 1.1 Transport Network layering; OTN supports a wide range of client signals

over DWDM [4].

From the figure above, it can be observed that OTN helps to remove one

unnecessary layer in the optical hierarchy, consequently, reducing cost and complexity

of the overall system. Also, OTN supports a wide range of client signals (IP, Ethernet,

ATM, SONET, SDH) all over a single wavelength, and make it easier for management

and wavelength services.

1.2 Problem Statement

The migration to IP/Ethernet application globally is forcing enterprises to

address two major WAN issues: converging TDM and packet networks to reduce

expenses, and improving network and service management to support delay-sensitive,

bandwidth-intensive applications.

3

Several problems aroused after two decades of using SONET and SDH as the

infrastructure for optical networks. Inefficient data transport was one of the main

reasons to search for a new optical transport protocol, as they were originally designed

for circuit switched voice traffic, not for packet-dominated high transmission services

of 40 Gbps or above [5]. Also, point-to-point was the only topology supported by

SONET and SDH, whereas new services require other topologies [6]. In addition to

those, there are some provisioning limitations leading to significant inefficiencies

when providing transport for short-lived on-demand services.

Moreover, there was need for new services that cannot be added to the current

transport protocols, such as a new channels to perform operations, administration,

management and provisioning (OAM&P) functions in a multiwavelength multi-signal

WDM/DWDM network; a need for a better and more powerful FEC for longer

distances and a need for a faster switching as SONET/SDH switches at

1.5Mbps/2Mbps (T1/E1 level) and 51Mps/155Mbps (STS-1/STM-1 level.

1.3 Objectives of Research

The objectives of this research are:

a. To model an optical transport network using a discrete event simulator

software and an optical software design suite.

b. To implement SONET and Packet Optical Network (G.709) protocols inside

the modelled transport network.

c. To analyze the performance of both systems in terms of delay and bit error rate

(BER).

1.4 1.4 Scope of Research

The goal of this research is to analyze and compare the performance of SONET

and Digital Wrapper G.709 in terms of packet loss, packet delay, Bit Error Rate (BER)

and bandwidth utilization. There are only few papers to study the performance of those

4

protocols and in only one aspect of the network. This research aims to take an eagle-

eye look at the performance of the overall network. The scope includes:

a. Design a three-node network scenario using OMNeT++ software.

b. Module an optical system in OptiSystem software.

c. Apply SONET and Digital Wrapper G.709 protocols in the modeled network.

d. Observe, analyze, and compare the performance of both protocols in terms of

the mentioned parameters for different bit rates.

40

REFERENCES

[1] Cisco Visual Networking Index: Forecast and Methodology, 2014–2019

White paper. May 2015. URL:

[2] http://www.cisco.com/c/en/us/solutions/collateral/service-provider/ip-

ngn-ip-next-generation-network/white_paper_c11-481360.pdf Accessed

in December 2015.

[3] Bianco, Andrea, et al. "CapEx/OpEx evaluation of circuit vs packet

switched optical networks." Optical Network Design and Modeling

(ONDM), 2013 17th International Conference on. IEEE, 2013.

[4] Manohar Naidu Ellanti Lakshmi G. Raman et al. Next Generation

Transport Networks - Data, Management and Control Planes. Springer,

2005.

[5] Knudsen-Baas, Per Harald. "OTN switching." (2011).

[6] Ciena - Expert Series: Optical Transport Networking 2014 – Accessed on

Nov 2015

http://media.ciena.com/documents/Experts_Guide_to_OTN_ebook.pdf

[7] Deliverable DJ1.1.1: Transport Network Technologies Study – 2010

[8] Valdar, Andy. Understanding telecommunications networks. Vol. 52. IET,

2006.

[9] Kartalopoulos, Stamatios. Next Generation Intelligent Optical Networks:

From Access to Backbone. Springer Science & Business Media, 2007.

[10] Okon, Unoanwanaile. Survivability, Resource Efficiency and Optimization

in Multi-layer Transport Networks. Diss. University of Alberta, 2012.

[11] Reference no.9 in “Understanding telecommunications networks” in

chapter 4

41

[12] A Brief Overview of SONET Technology –

[13] http://www.cisco.com/c/en/us/support/docs/optical/synchronous-

optical-network-sonet/13567-sonet-tech-tips.html - accessed in

December 2015

[14] ITU - Optical Transport Network (OTN) Tutorial -

[15] https://www.itu.int/ITU-T/studygroups/com15/otn/OTNtutorial.pdf

accessed December 2015

[16] Stuart Whitehead, OTN – what is it and why is it? Anritsu - 2014

[17] R. Gendron and A. Gidaro, “G.709 OTN Overview – An Overview”

accessed December 2015, available online:

[18] http://documents.exfo.com/appnotes/anote153-ang.pdf

[19] Stuart Whitehead , OTN – what is it and how does it? Anritsu - 2014

[20] Kimsas, A.; Overby, H.; Bjornstad, S.; Tuft, V.L., "A Cross Layer Study of

Packet Loss in All-Optical Networks," in Telecommunications, 2006. AICT-

ICIW '06. International Conference on Internet and Web Applications and

Services/Advanced International Conference on , vol., no., pp.65-65, 19-

25 Feb. 2006.

[21] OMNeT++ website https://omnetpp.org/intro

[22] White Paper: A G.709 Optical Transport Network Tutorial by Guylain

Barlow from ViaviSolution.com.

[23] the Center for Applied Internet Data Analysis (CAIDA) Website:

https://www.caida.org/research/traffic-

analysis/pkt_size_distribution/graphs.xml Accessed in June 2016

[24] A Sensible Low-Latency Strategy for Optical Transport Networks by

Optelian http://www.optelian.com/media/178800/Optelian-Low-

Latency-Strategy-for-OTN-WP.pdf Accessed in June 2016

[25] Low Latency – How Low Can You Go? By Infinera

https://www.infinera.com/wp-

content/uploads/2015/11/WP_Low_Latency_Design_D.pdf accessed in

June 2016

[26] Henderson, M. (2001). Forward Error Correction in Optical Network. Mar,

27, 1-18.