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