ABSTRACT
Admission Control is a vital component for end-to-end Quality of Service (QoS) delivery in a packet flow network. It is more effective when implemented at the edge of the network. The edge of a mobile network is dominated withmultiplexer which either uses Synchronous Digital Hierarchy (SDH) or Wavelength Division Multiplexing (WDM) for transport. The edge of the carrier Ethernet network suffers QoS due to packet loss and underutilization of bandwidth. Measurement-Based Admission Control (MBAC) Algorithm which reduced the IP Packet Loss Ratio (IPLR) of WDM system by 30.36% and SDH system by 25.34% was setto be achieved in this work. The developed Algorithm was also set to improve the bandwidth utilization of WDM system by 30.36% and bandwidth utilization of SDH system by 25.34%. The developed Algorithm was implemented using C-sharp (C#) platform. Based on the simulation results, WDM system IPLR was reduced by 30.36% and SDH system IPLR was reduced by 25.34% as compared to the measured data from the network result before implementation of the MBAC algorithm. WDM system bandwidth utilization was improved by 30.36% and SDH system bandwidth utilization was improved by 25.34% as compared to the baseline result before implementation of the MBAC Algorithm. From the t-test results obtained, the probability levels (P-values) of IPLR and bandwidth utilization for both edge systems were less than 0.05. This implied that the developed Algorithm has better performance in comparison with the measured data from MTN Lagos network.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgement v
Table of Content vi
List of Figures x
List of Tables xi
List of Abbreviations xiii
Abstract xv
CHAPTER ONE: INTRODUCTION
1.1 Background on Admission Control 1
1.2 Justification of the Research 3
1.3 Problem Statement 3
1.4 Aim and Objectives 3
1.5 Scope of the Research 4
CHAPTER TWO: LITERATURE REVIEW
2.1 Introduction 5
2.2 Review of Fundamental Concepts 5
2.2.1 Carrier Ethernet 5
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2.2.2 Synchronous Digital Hierarchy 6
2.2.3 SDH Frame Structure 8
2.2.4 Wavelength Division Multiplexing 9
2.2.5 Performance Measurement Methods in an IP-Based Network 11
2.2.5.1 Intrusive Performance Measurement 12
2.2.5.2Non-intrusive Performance Measurement 12
2.2.6 Equivalent Capacity 14
2.2.7 Validation of Developed Algorithm 25
2.2.7.1 Welch’s T-Test 25
2.2.7.2 Parametric Welch‟s T-Test 26
2.2.8 IPLR Percentage Reductions and Bandwidth Utilization 28
2.3 Review of Similar Works 29
CHAPTER THREE: METHODOLOGY
3.1 Introduction 34
3.2 Collection of Measured Data 34
3.3 Development of MBAC Algorithm for WDM and SDH System 37
3.4 Simulation of MBAC Algorithm 39
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3.5 Validation 39
CHAPTER FOUR: RESULTS AND DISCUSSIONS
4.1 Introduction 41
4.2 Simulation Results Obtained 41
4.3 Evaluation of the IPLR and Bandwidth Utilization 42
4.3.1 Simulation Results of IPLR for WDM System 42
4.3.2 Simulation Results of Bandwidth Utilization for WDM System 44
4.3.3 Simulation Results of IPLR for SDH System 46
4.3.4 Simulation Results of Bandwidth Utilization for SDH System 47
4.4 IPLR Percentage Reductions and Bandwidth Utilization 49
4.5 Validation of Results of T-Test 54
4.5.1 Results of measured Data 54
4.5.2 Results of Simulated Data 55
4.6 Validation of T-Test Results Obtained 56
4.6.1 Bandwidth Utilization T-Test Results 56
4.6.2 IPLR T-Test Results 58
CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS
5.1 Summary 59
5.2 Conclusions 59
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5.3 Significant Contributions 60
5.4 Limitations 61
5.5 Recommendations for further work 61
REFERENCE 62
APPENDICES
Appendix A: Average Weekly Measured Data 66
Appendix B: Program Pseudo code 67
Appendix C: Simulated Results 84
CHAPTER ONE
INTRODUCTION
1.1 Background on Admission Control
Wireless mobile network services have evolved over time from low bandwidth consumption services to high bandwidth consumption services (Cisco, 2016). This has forced network providers to upgrade their mobile backhaul to IP-based because these high bandwidth consumption services (like streaming media, video, and interactive gaming) are IP-based that require IP-based network. These different services require Quality of Service (QoS) which must be supported by a well-defined IP and Ethernet based network. A well-defined IP- and Ethernet- based network which should satisfy the QoS requirements of these services must exercise admission control at the edge and core of its network to control the amount of traffic injected into its network (Heena et al, 2011). Admission control is a set of actions, consecutively executed, to decide whether a customer can be admitted into a network segment or not (Bohnert, 2011). It is a congestion avoidance mechanism. The primary role of admission control in a QoS enabled network is to control the amount of traffic injected into the network so that congestion is avoided (Gaoet al, 2012).
There are different types of admission control methods and their difference is mainly due to the different types of operation and methods of implementation. Some Admission control methods are based on mathematical calculations and statistics indicators, others on measured traffic (Chromy et al, 2013). Some of the implementation methods for admission control are (Bohnert, 2011):
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i. Integrated admission control placement
ii. Edge based admission control placement
iii. End point admission control placement.
Integrated Admission Control Placement: This kind of Admission control placement is implemented in each router between the source and destination. A new customer request is admitted hop-by-hop from its origin to its destination.
Edge Based Admission Control Placement: This is Admission control implemented in edge (ingress/egress) routers. It helps in regulating traffic load on access links.
Endpoint Admission Control Placement: This Admission control is implemented in customer equipment. It could be on application software, access routers or switches.
In general, admission control methods are divided into two categories: Parameter-Based Admission Control (PBAC) and Measurement-Based Admission Control (MBAC) (Chromy et al, 2013). PBAC method is based only on the current active traffic and on the characteristics of the total active traffic. This method may not be optimal, because it does not rely on a new incoming traffic. MBAC method does not specify how source parameters are obtained, but makes measurements on the network running in real time. This method can achieve higher network utilization because serving a new data flow in the network is common. Common criteria of admission methods are the ability to allocate bandwidth for all actual data flows in cases not exceeding the total capacity limit.
This research work aims to develop a robust Measurement Based Admission Control (MBAC) algorithm which will reduce IP Packet Loss Ratio (IPLR) and improve bandwidth utilization on the edge of carrier Ethernet network.
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1.2Justification of the Research
Telecommunication industry is ebbing towards all IP-infrastructure. For successful transformation to all IP networks, network providers must tackle network performance issues like packet loss and bandwidth utilization to have a stable QoS. The study identifies QoS due to packet loss and underutilization of bandwidth at the edge of carrier Ethernet network.MBAC algorithm which reduced the packet loss and improved bandwidth utilization of edge carrier Ethernet network was developed. This resulted in optimized network model that justifies the significantcontributions and improvement of QoS.
1.3Problem Statement
The Management-Based Information (MIB) interface of edge equipment has a lower sub-layer (ifHcInUcastPkts) and higher sub-layer (ifHcOutUcastPkts) (ITU-T M.2301, 2002). The lower sub-layer is the layer at which packets arrive at the interface of the equipment and they are delivered to the higher sub-layer.
In most of the literature reviewed, it was discovered that the bandwidth of the higher sub-layer is less than the packets sent by the lower sub-layer. This causes significant value of IP Packet Loss Ratio (IPLR) and under-utilization of higher sub-layer bandwidth, hence, a major problem this work is set to address.
1.4Aim and Objectives
The aim of this research work is to develop a Measurement Based Admission Control (MBAC) algorithm for edge of carrier Ethernet network to reduce packet loss and improve bandwidth utilization.
The research objectives are centered on the following four items:
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i. Collection of measureddata from MTN Lagos network for the period of three months so that it can be studied,analysed, and used for developing the MBAC algorithm.
ii. Developing MBAC algorithm for edge of carrier Ethernet network deployed with WDM and SDHto reduce IPLR and improve bandwidth utilization.
iii. Simulating the developed MBAC algorithm using C-sharp (C#) software platform to obtain results for IPLR and bandwidth utilization.
iv. Validating the MBAC algorithm simulated results by comparing them with the data collected from MTN Lagos network.
1.5 Scope of the Research
The scope of the dissertation is reduction of IPLR and maximization of bandwidth utilization on edge of carrier Ethernet network. The study is based on developing a MBAC algorithm for edge of carrier Ethernet network deployed with SDH and WDM to reduce IPLR and increase bandwidth utilization.
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