techniques for applying lean principles in service …1154814/fulltext02.pdf · 2017. 11. 9. ·...

Master of Science in Electrical Engineering with Emphasis on Telecommunication systemsOctober 2017

TECHNIQUES FOR APPLYINGLEAN PRINCIPLES IN SERVICEDESIGN AND DEPLOYMENT IN

FUTURE NETWORKSDESIGN AND IMPLEMENTATION

NAYYAR IQBAL

Faculty of ComputingBlekinge Institute of TechnologySE–371 79 Karlskrona, Sweden

This thesis is submitted to the Faculty of Computing at Blekinge Institute of Technologyin partial fulfillment of the requirements for the degree of Master of Science in ElectricalEngineering with Emphasis on Telecommunication systems . The thesis is equivalent to 20weeks of full time studies.

Contact Information:Author(s):Nayyar IqbalE-mail: [email protected]

University advisor:Prof. Kurt TutschkuDepartment of Communication Systems

Faculty of Computing Internet : www.bth.seBlekinge Institute of Technology Phone : +46 455 38 50 00SE–371 79 Karlskrona, Sweden Fax : +46 455 38 50 57

Abstract

Context. Network slicing is a type of virtual network which aims at group-ing data plane and control plane resources into these virtual functions. Net-work slicing utilizes concepts from SDN and NFV in all public networks(fixed networks, cellular mobile networks). Deploying SDN and NFV com-mercially convey more noteworthy network flexibility by empowering con-ventional networks to be portrayed into virtual network components thatcan be associated. Accordingly, Network slicing enables various virtual sys-tems to be made over a common physical infrastructure.Objectives. The aim of the thesis is to develop a rather comprehensiveworkflow for defining a service design model and appropriate data struc-tures. Our focus is to make service deployment fast and cost efficient byreducing waste for the roll out and orchestration of network slice as a slice.Ultimately, applying Lean concepts for reducing the waste and investigat-ing how Lean methodology benefits model to increase the effectiveness ofservice deployment.Methods. The core of this thesis work is to design a workflow for servicedeployment and applying lean principles to it. To elaborate, this thesiswork involves in a research of papers from academic and standardizationorganizations. Data modeling language is used for modeling a service andseparation of concerns approach is used for building data structures fromthat data model. Lean management concepts are interpreted to service op-erations and mapped to service design for identification of lean wastes andoptimizing them.Results. The results of this work incorporate comprehensive workflow andservice design model with lean implementation by addressing the use caseof network slice as the new service. To test the use-case, we simulate the ex-ecution of service roll-out. Eventually, optimization algorithms are appliedand the improvement of the execution plan is tested.Conclusions. It can be concluded that scalability might be the challenge indeveloping markets, while cost-efficiency and Average revenue per user arethe main objectives in mature markets nowadays. Unlike network perfor-mance where several parameters already exist for monitoring performance,there are no metrics defined for network slice for designing and optimizingpurposes. So by applying principles, lean waste like overproduction andwaiting time can be mapped to the over-provisioning and waiting time forconfiguring service. It aimed at increasing the efficiency of service provi-sioning for example waiting until a service is provisioned.

Keywords: Lean Management, Network slice, Service, Virtualization

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Acknowledgment

First of all, I am grateful to Almighty Allah for blessing me strength and oppor-tunity to complete this thesis work to the best of my endeavors. I would liketo express my sincere gratitude to my advisor Prof. Kurt Tutschku for the con-tinuous support during my master thesis and for his patience, inspiration, andenormous knowledge. It is a great pleasure for me to work under his supervisionsince his guidance helped me during research and writing of this thesis. I couldnot have imagined having a better advisor and mentor for my master’s study.

I am utilizing this opportunity to thank all faculty members specially Prof.Wlodek Kulesza, Prof. Adrian Popescu, Prof. Patrik Arlos and Prof. MarkusFiedler for their teaching style and enthusiasm during my degree program. I amsincerely thankful to them for sharing their honest and remarkable experiencewith me.

I would like to thank my fellow students and friends for their encouragementand support. Zaheer, Muneeb, Farhan, Ali ,Amjad Mudassir, and Noman havebeen enduring in their personal and professional support during the time I spentat the University.

Last but not least, none of this could have happened without my family. Tomy parents and my elder sister for providing me through moral and emotionalsupport throughout my studies. This achievement would not have been possiblewithout them.

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Abbreviations

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Contents

Abstract i

1 Introduction 11.1 Problem Overview And Problem Statement . . . . . . . . . . . . 11.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Objective of Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 Research Questions . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 Thesis Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.6 Split of Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 Related Work 7

3 Concepts, Techniques And Challenges 113.1 Service Function Chaining . . . . . . . . . . . . . . . . . . . . . . 113.2 Network Slicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.3 Challenges in Service Function Chaining, Service & Slice Deployment 123.4 Data Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.5 Modeling Languages for Network Configuration . . . . . . . . . . 14

3.5.1 General Overview . . . . . . . . . . . . . . . . . . . . . . . 143.5.2 SMIv2 Modeling Language . . . . . . . . . . . . . . . . . . 153.5.3 YANG Data Modeling . . . . . . . . . . . . . . . . . . . . 153.5.4 Capabilities of the YANG-Model . . . . . . . . . . . . . . 17

3.6 Separation Of Concerns . . . . . . . . . . . . . . . . . . . . . . . 173.7 Service Orchestration . . . . . . . . . . . . . . . . . . . . . . . . . 183.8 Advanced Remote Configuration Of Virtual Network Elements . . 193.9 Lean Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4 Methodologies 234.1 YANG Data Modeling . . . . . . . . . . . . . . . . . . . . . . . . 234.2 Network Element Configuration . . . . . . . . . . . . . . . . . . . 254.3 Mapping Of Data Structures . . . . . . . . . . . . . . . . . . . . . 264.4 Lean IT Management . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.4.1 Types of Wastes . . . . . . . . . . . . . . . . . . . . . . . . 274.4.2 Optimization Aims . . . . . . . . . . . . . . . . . . . . . . 28

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4.4.3 Mapping of Lean Wastes to Optimization Aims . . . . . . 29

5 Results And Analysis 305.1 Comprehensive Deployment And Management Workflow . . . . . 305.2 Analysis And Evaluation Concept . . . . . . . . . . . . . . . . . . 315.3 Performance Results . . . . . . . . . . . . . . . . . . . . . . . . . 37

5.3.1 Initial Quantification of Improvements by applying LeanConcepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

5.3.2 Optimization Criteria . . . . . . . . . . . . . . . . . . . . . 38

6 Conclusion And Future Work 396.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396.2 Answers to Research Questions . . . . . . . . . . . . . . . . . . . 406.3 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

References 42

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List of Figures

1.1 Phases involved in Network slice as a service . . . . . . . . . . . . 3

3.1 A vCPE service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.2 Network slicing Concept . . . . . . . . . . . . . . . . . . . . . . . 123.3 Service orchestration with NFV and SDN . . . . . . . . . . . . . 19

4.1 Basic NETCONF session . . . . . . . . . . . . . . . . . . . . . . . 26

5.1 Workflow in service deployment . . . . . . . . . . . . . . . . . . . 305.2 Configuration of Cisco CSR 1000v in AWS . . . . . . . . . . . . . 325.3 Creation of a Key pair. . . . . . . . . . . . . . . . . . . . . . . . . 325.4 Configuration on Cisco CSR Router step1 . . . . . . . . . . . . . 335.5 Configuration on Cisco CSR Router step2 . . . . . . . . . . . . . 335.6 Configuration of network element for case 1 . . . . . . . . . . . . 375.7 Configuration of network element for case 2 . . . . . . . . . . . . 37

6.1 Architecture of Thesis . . . . . . . . . . . . . . . . . . . . . . . . 39

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List of Tables

1.1 Contribution of work for each section in this document . . . . . . 6

3.1 Differences between SNMP and NETCONF . . . . . . . . . . . . 21

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Listings

3.1 Leaf Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.2 Leaf-List Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.3 Container Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.4 List Nodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.5 bear-hunting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.6 bear-eating.rb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.7 bear-hunger.rb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184.1 Sample example of YANG Model . . . . . . . . . . . . . . . . . . 235.1 Design of YANG Model for Service . . . . . . . . . . . . . . . . . 335.2 Script of Tool for pushing configuration . . . . . . . . . . . . . . . 35

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Chapter 1Introduction

1.1 Problem Overview And Problem StatementConventional networks are populated with a substantial and expanding assort-ment of proprietary equipment. More often launching integrated services (voice,data etc.) requires the space, energy and dedicated hardware to oblige them inthe physical infrastructure. This hardware-centric approach has several limita-tions. Whenever operators want to scale up their network to accommodate moreclients or features, they have to spend huge amount of money for upgrading thesededicated boxes. Similarly, most of the organizations owns a variety of equip-ments from several vendors.This demands high level of expertise for multi vendorenvironemnt. In addition to this, hardware based machines quickly achieve theend of life and thus operators have to go through the design-deployment cyclewith practically little or no profit. More awful, hardware life cycles are getting tobe noticeably shorter as innovation and technology advancement quickens, hin-dering the roll out of new income acquiring network services [1].

Conventional networks have both control plane (where and how to forward thetraffic) and data plane (forwarding of traffic to destination) functionalities in oneunit. With the advancements of social media, IoT devices, and cloud computingquickly bring the conventional networks to their limits. This happens becausemost of the forwarding decisions are defined in hardware based devices and it isnot possible to program these forwarding rules easily. Consequently, network op-erators have no control over these predefined decisions in conventional networks.In this manner, all packets heading off to the same destination might be directedalong the same path and hence treated in a similar manner. It might cause issuesfor services having special requirements like security concern or low latency rate.For instance, bank network requires secure and dedicated links for their networks.So, there is a need to have a dedicated application specific network control [2].

Furthermore, by choosing virtualization technologies, many endeavors oper-ate on Internet Protocol based networks and provide different sort of traffic likevoice, data, and video traffic. As existing systems can give different Quality of

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Chapter 1. Introduction 2

Service levels to various applications. So, in conventional networks, there is needto configure each vendor’s equipment separately and adjust parameters such asnetwork bandwidth and QoS according to requirement of the service. As a resultof its static nature of conventional networks, the network cannot adapt accord-ing to evolving traffic application and user demands easily. Hence, the idea of a"slice" as network service has been introduced [3].

The aim of network slice is to logically isolate the network functions and re-sources within a network entity as per business requests and to provide networkas a slice. Despite the fact, the idea of NS is still new, comparable technologiesalready exist. One of that technology is virtual Local Area Networks (VLANs),which is defined in IEEE 802.1Q networking standard and it can be viewed as thepredecessor of Network Slice. “VLANs is a group of devices on one or more LANsand provides a single broadcast domain that might or might not be physicallyconnected.” Nevertheless, the cellular networks are facing some difficulties for NSbecause in cellular networks various parameters need to be customized for bothcontrol plane and data plane to make a group of connections as a logical network.

Network Function Virtualization (NFV) and Software-defined networking (SDN)play an important role to make NS a reality by promoting a cost-effective ap-proach for building dedicated networks. NS enables operators, by using NFV andSDN technologies, to customize networks as per different necessities of mobile ser-vices. Hence, NS is gaining a huge interest from both industry and research. Forinstance, Fifth Generation Infrastructure Public Private Partnership (5G-PPP)project presents a business model of Network Slice among different vendors andservice providers, retail providers and end users [4].

NFV is a network design concept which utilizes IT virtualization technologiesto virtualize the whole set of network functions into building blocks that may beconnected to create communication services. In this way, with the introductionof NFV network functions can be executed as software on the top of hardwareinstead of dedicated hardware for router, switch, firewall, Deep Packet Inspection(DPI), Broadband Remote Access Server (BRAS), Network Address Translator(NAT) etc.[5].

The concept behind the NFV is not only to virtualize the network functionsbut also to interface them to design them as a network slice. Traditional networkslike Global System for Mobile Communications (GSM) and General Packet RadioService (GPRS) does not provide the advanced network functions like Parentalcontrol, smart cache, Intrusion detection system, firewall etc. These advancednetwork functions cannot be generic in fact they need to be specific according tothe needs of service. This introduces the notion of network slice. Network slice islike setting a specific network to provide advanced functions over infrastructure


and it enables both data transport and network control. The Idea behind intro-ducing network slice is to provide better network control which is not available intraditional networks. It provides benefits to the business such as time reductionfor service provisioning, and dynamic and elastic scale for network services[6].Challenges which aimed to be solved by network slice are described below:

• Implementation of a dedicated network is expensive.

• Complicated process for configuring network elements.

Figure 1.1: Phases involved in Network slice as a service

The Fig.1.1 demonstrates the four stages of product management of Networkslice as Service. In the first stage, a network slice is designed by operators fora general vertical enterprise as indicated by the portrayal of the service model.It could be also referred as a vertical industrial template. But this general ser-vice model is not prepared for instantiation at this stage because of lacks inputinformation such as SLA from buyers. With the end goal to sell this service tocustomers, operators have to price the slice service in terms of the subscribernumber, QOS and spectrum resources. In the second stage, product managers ofoperators prepare the presentation and case analysis of the slice service to awareand promote consumers, so that they understand its value. Before forwardingit to next stage, an internal review will be performed before releasing into themarket. In the third stage, customer orders the slice service and provide its re-quirements to the vertical template like slice coverage, capacity, and SLA etc.


The network slice service is deployed and executed in the fourth stage. In thisstage, both the operator and customer can monitor the status of the connectionsand service. In the final stage of product management, if the slice service is notappropriate to offer in the marketplace, operators can dispose of it to end its lifecycle.

1.2 MotivationOrganizations in the service sector are constantly under pressure to deliver goodcustomer service, faster response times and valuable support for their customers.It means organizations need to take a deep inspection at their activities and iden-tify waste such as idle times, transport, whether processes are taking too long,errors, inventory and over-producing. The concept of lean management can beseen as very promising alternative optimization concept for for efficient produc-tion of both goods and services. The appealing feature of lean is the applicationof alternatives to optimization criteria which are not typically technical criteriasuch as packet delay. These criteria can be denoted as wastes. These lean prin-ciples are already implemented successfully in organizations like Intel, Ryanair,Ford, Wipro. Lean principles involve optimizing human effort, reducing capi-tal investment, reducing the amount of raw materials and reducing the time todeliver.

1.3 Objective of ThesisThe aim of our thesis is to obtain deeper knowledge and find interpretationsof what lean can bring out to telecommunication service industry. It involvesinvestigating how to apply Lean IT principles to define a service(network slice)design model including a generic data structure. Thus, making service deploymentfast and cost efficient by reducing waste i.e. specifying among others an efficientroll-out plan that includes element and flow configuration. Lean in this thesiscontext does not aim at improving data transport but aims at improving steps todeliver service. In order to achieve the goal, following objectives will be covered.

• To define a general model for data structures for a new telecommunicationservice deployed under Lean IT principles.

• To address the use case of network slice as the new service.

• To find a temporal way for the service design, e.g. an appropriate schedulefor the roll-out.

• To develop a concept to test whether the model is efficient or not.


• To simulate the execution of service roll-out.

• Eventually, to apply optimization algorithms to improve execution plan.

1.4 Research QuestionsRQ1. What are feasible, appropriate, or optimal data structures and orchestra-tion plans for service deployment in future networks for slice-based services?

RQ2. How can one instantiate the data structures with appropriate content suchthat it can be used for testing and configuration of network elements?

RQ3. How can we transfer the wastes of lean management into optimizationcriteria for slice-based future network services?

1.5 Thesis StructureThis thesis work is structures as follows:

Chapter 2 provides some related work in this research area. This section cov-ers some previous research on Network Slicing, Service Design, Yang modelinglanguage and Lean IT principles.

Chapter 3 discusses about the concepts and techniques that are used in thisthesis work along with their motivation. It also reveals some of the expectedchallenges that arises while conducting this research.

The proposed methodology for the research is presented in chapter 4. This sectionexposes the methods for how the network topology can be designed and modeledusing YANG modeling language, Mapping of data structures, concepts of LeanIT principles to identify waste.

Chapter 5 presents the results which are more like analysis such as configura-tion and deployment of network slice, Mapping the lean wastes to slice designand deployment.

Chapter 6 provides the conclusion of the thesis work based on results and fewideas for future research. This section also includes answers to research questions


1.6 Split of WorkThis section provides you details about the contributions of work in this docu-ment.

Section Topic Contributor1 Introduction Nayyar Iqbal,

Phani Varanasi1.1 Problem Overview And Problem State-

mentNayyar Iqbal,Phani Varanasi

1.2 Motivation Nayyar Iqbal,Phani Varanasi

1.3 Objective of Thesis Nayyar Iqbal,Phani Varanasi

1.4 Research Questions Nayyar Iqbal1.5 Thesis Structure Nayyar Iqbal,

Phani Varanasi1.6 Split of Work Nayyar Iqbal,

Phani Varanasi2 Related Work Nayyar Iqbal,

Phani Varanasi3 Concepts, Techniques And Challenges Nayyar Iqbal,

Phani Varanasi4 Methodologies Nayyar Iqbal,

Phani Varanasi5 Results & Analysis Nayyar Iqbal6 Conclusion & Future work Nayyar Iqbal

Table 1.1: Contribution of work for each section in this document

Chapter 2Related Work

Foukas et al. [7] discussed the state of the art in 5G network slicing. From serviceoriented view, 5g aims at providing wide range of services which may have dif-ferent requirements and possibly some of them are to be customized according totype of devices. To cater these challenges, notion of network slicing is introducedwhich aims to slice the network on a per service basis. They also presented aframework with several slicing proposals which are infrastructure, network func-tion, and service layers along with the MANO entity.

Li et al. [8] addressed some challenges and opportunities of network slicingfor 5G, as it has become a key in the service-oriented 5G network architecture.This helps service providers to deploy their applications and services in a quickand a flexible way to accommodate diverse services requirements. Resource shar-ing, dynamic creation and management, isolation among network slices, mobilitymanagement, security and wireless resource virtualization in network slicing aresome of the challenges highlighted by the authors.

Chiosi. et al. [9] prepared the white paper to outline the benefits and chal-lenges for Network Functions Virtualization. White paper explained conventionalnetworks are getting over populated with a substantial and expanding assortmentof proprietary hardware equipment. In order to launch a new service, operatorshave to face challenges like resources (like power and space), costs of energy, in-vestment, small hardware life cycles etc. Network Function Virtualization is thetechnology whose aim is to separate network functions from dedicated hardwareand virtualized them to host them on industry standard high volume hardwareequipment. They also emphasized that there is need to obtain more benefit fromNetwork Functions Virtualization if its features are combined with Software De-fined Networking (which aims at to programmed the network to separates thenetwork’s control and data planes).

Bhamare et al [10] presented service function chaining as an approach forproviding a flexible and an economical choice to present static environment forservice providers. As a result, network operators have chosen to use versatile vir-

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Chapter 2. Related Work 8

tual resources to implement network services over static inflexible physical model.They have also discussed the scope of SFC and standardization works carried outby organizations like ETSI, ITU-T and IETF SFC working group. Some of theresearch areas for SFC are service description languages, SFC data-plane etc. todefine the service flows and the service function forwarders.

Medhat et al. [11] highlighted service function chaining concept and archi-tecture, which adopts the benefits of both NFV and SDN. By adopting thesetechnologies, it aims to provides efficient and effective deployment and orchestra-tion of service functions. Likewise, they presented some common limitations andchallenges applicable to the SFC concept and architecture. Some of the challengesof SFC are placement of Service functions and resource management. These chal-lenges need to be resolved in order to ensure highspeed communication to deliverin SDN networks.

Zhou et al. [12] explained the concept of hierarchal network slicing as a service.Idea is to facilitate operators so that they can introduce and provide customizedend to-end cellular networks as a service. Keeping in view the relationship be-tween customers and operators, Business models of network slicing as a servicecan be further classified into different classes. So that It will also help operatorsto design customized network slices for industries in an agile way.

Brown [13] prepared this white paper which aims at service chaining use cases,their architecture and implementation. This white paper features the advantagesof dynamic service chaining, how it empowers operators to dynamically createservice chain using virtualized network functions. Due to Ossification, operators’ability to address rising use cases and business models is constrained. In order tocope with rapid innovation at the application layer and maintain good revenuegrowth, there is need to avoid and limit unnecessarily restriction to market fortelecom services. It also clarifies the service relationships between the serviceprovider and customer in the form of the service chaining point of view.

Choi et al. [14] presented a yang data model for Service function chainingcontrol plane. They defined the requirements of management of SFC based onthe standardization document and accordingly they designed and modeled Yangdata model for management operations like path management, load balancing,SFC topology etc. for SFC control plane.

Clemm et al. [15] defined an abstract YANG data model for network/servicetopologies and inventories. Data model can be divided into two sections. The firstsection of the data model demonstrates a network data model which defines thenetwork hierarchies and maintain an inventory of nodes contained in a network.The second section of the data model expands the basic network data model with


information to portray topology information. The benefit of this separation isto expand network inventory information separately and without any trouble fornetwork topology into the network data model.

Hicks et al. [16] proposed a conceptual framework for a set of lean principlesand characterizes the classifications of waste within the context of informationmanagement. From an organization point of view, goal of information manage-ment is to make sure valuable information is gained and exploited to its full extent.There is a need to build up a new approach for supporting the improvement ofinformation management and the overall information management system.

Leite et al. [17] analyzed more than 70 papers about “lean thinking” whichconcentrate on service-sector. They highlighted the companies that are applyinglean service principles and, the best tools, and practices applied in the usage oflean principles. Although, it can be said that lean does not have a single modelof tools and there is no standard set of guidelines that defines which, when andwhere are apply lean principles to services. In this way, a collection of the bestpractices is applied to particular needs of an organization and its line of servicesto create extensive monetary and budgetary outcomes and financial outcomes.Researches demonstrates details of business service area such as health, govern-ment (public administration), logistics, offices, teaching, retail and others wherelean can be applied. Further investigation of these areas helps to translate thebenefits from one service area to another and propose an implementation strategyto services in general.

Jasti et al. [18] investigated the analysis of literature review of lean produc-tion and provide conceivable directions to satisfy the existing research gap in thisarea. The study proposed to build practical-oriented frameworks, implementa-tion of lean production principles as a framework instead of a piecemeal approachand to focus more on empirical research to build and verify theory researchers.Further, they recommended to develop frameworks which can be applied to allactivities in an organization rather than a specific activity of the organization.

Vignesh et al.[19] presented a thorough bibliographic investigations with sev-eral lean practices through an assortment of methodologies like service improve-ment, manufacturing, supply chain, market and retailing approaches, etc. and theframeworks that they have chosen for effective implementation of lean practicesin the service enterprises. Through particular approaches, numerous propositionhave been made to enhance the workflow through the use of lean methodologiesto expel the non-value added activities. They explained the examples of an insur-ance company and Danish municipalities under public service sector where theysuccessfully applied the lean approach through five-stage process. Another areais to apply Lean in Marketing Strategy. A typical example of this is service call


centers where operational cost can be reduced and quality of customer servicecan be increased through the adoption of lean service tools. Additionally, Leancan likewise be utilized in retailing, where advertising can be used to grow anddevelop the overall sales by motivating customer. Also, lean operation and stablepricing can be used for building up an alternative business model to effectivelyaccomplish notable advantage.

Chapter 3Concepts, Techniques And Challenges

3.1 Service Function ChainingService Function Chaining (SFC) is a service concept which has the capabilityto characterize an ordered list of network functions like Parental control, smartcache, Intrusion detection system, firewall etc. By doing so, these network func-tions stitched together to form a virtual chain.

Figure 3.1: A vCPE service

The Fig.3.1 shows an example of telecommunication service, virtual customerpremises equipment which uses service chaining concept. Here Customer-premisesequipment (CPE) represents router with internet facility. CPE access the virtualhome gateway (VHG) through virtual CPE. Service provider network has differ-ent parts/components and is connected to both virtual home gateway (VHG) andcarrier grade-NAT gateway. the highlighted part in the Fig.2 is a service chainwhich has Virtual Network Functions (VNF) like parental control, video opti-mization and security are implemented in these components through ApplicationProgram Interface (API). By utilizing this service chaining, service providers pro-vide virtual CPE solutions both to its enterprise and residential customers [20].

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Chapter 3. Concepts, Techniques And Challenges 12

3.2 Network SlicingNetwork Slicing intends to logically separate the set of network functions andresources within one network. Network slicing empowers operators to providenetworks on an as-a-service which reduces time-to-market for new services andincreases operational efficiency while offering optimal support for customer andcommercial demands.

Figure 3.2: Network slicing Concept

Fig.3.2 demonstrates the assignment of devices such as devices like tablets, In-ternet of Things (IoT) devices etc. to the network slices. The service orchestratorand network orchestrator are the entities which deal with applications, platforms,and infrastructures. Eventually, they map the different service and network de-mands for various industries like media, automotive, health and utility energy.The orchestration is a controlling unit which empowers automation of a processby incorporating at least two applications or services. Besides automation, it canlikewise streamline and optimize processes [21].

3.3 Challenges in Service Function Chaining, Ser-vice & Slice Deployment

Advancements in the field of SDN and NFV enable ISPs to deploy network servicesover the virtualized frameworks. In spite of the fact that NFV alongside SDNprovides flexibility to Internet Service Provider (ISPs)for deployment of theirnetwork services. There are still some challenges which are described below:

• The creation, deletion, and interconnection of these virtual capacities is achallenging task due to the dynamic end-user demands and the networkparameters etc.

• Virtual Functions may need to be executed in a particular order to give acomplete end-to-end network service.


• The order of execution relies upon the kind of client requests for and is verydynamic in nature

In the same way service deployment is also challenging task. Following arethe minimum requirements which need to be met for deploying a service.

• There is a possibility that a segment may rely upon a service, it means itneeds the functionality of that service for proper execution.

• Time conditions might be absolute, relative or even rehashed at regularintervals. For instance, it is conceivable that some servers need to keeprunning at a given time, or to run every three hours or to run just on thefirst of the month.

• A client should not get a service for which client is not subscribed andpaid for. There must be some sort of authorization for checking whether acustomer is authorized to use or access requested service.

3.4 Data StructuresData Structure is a methodical approach to arrange data keeping in mind theend goal to utilize it effectively. Following terms are the basic terms of a datastructure. Each data structure has an interface which represents the set of op-erations that a data structure can support i.e. the list of supported operations,type of accepted parameters and return type of these operations. As applicationsare getting complex and information rich, there are three regular issues that ap-plications face nowadays.

Data SearchConsider a stock of 1 million items in a store. If the application is to look throughan item, it needs to look through that item from 1 million items. As data grows,searching of items into the store will become slower and slower.

Processor speedIn spite of the fact that being high, processor speed will drop eventually if thedata grows to billion records.

Multiple requestsAs a large number of users can look data at the same time on a web server, sothere is a possibility that even the fast server may fail some day during searchingthe data.

To take care of the above-mentioned issues, data structures act like a savior.Data can be sorted out in a data structure such that all items may not be needed


to be searched and still one can search the required data instantly. The philos-ophy for choosing and designing suitable data structures is a well-demonstratedidea from software engineering for example concept of Separation of Concerns.Separation of Concern upgrade readability and ease of use in light of the fact thatan individual concern can be isolated into concern and consequently easy to read,maintain and reuse. This will be matched with the requirement of slice-basednetwork services.

Service deployment can be designed in an object-oriented method. Since net-work slice contains a set of services which are interconnected to each other. Inorder to design a network slice, we need to select an appropriate data structuresand the relationship between data objects should be scalable. In this way, dataobjects serve as a sub services and utilizing this approach has a few advantages.Also, it is expected that there might need to scale services in future as it is re-quired by users and eventually it might develop to hold an arbitrary number ofobjects [22].

3.5 Modeling Languages for Network Configura-tion

3.5.1 General Overview

Data Models characterize managed objects at a lower level of abstraction. Theyinclude implementation and protocol-specific details, e.g. rules that explain themapping of managed objects onto lower-level protocol constructs. The greaterpart of the management models institutionalized to date is Data Models. Someof the common examples are Policy Information Base (PIB), Management Infor-mation Base (MIB) etc.[23].

Data modeling causes network specialists to guarantee the rightness of inputdata. Suppose service provider want to turn up a new customer interface. So, thenetwork engineer must apply some sort of configuration to turn it on. There isa possibility that operator accidentally may type the wrong netmask. If a wrongconfiguration that uses an invalid IP address and netmask or may be any syntaxerror could cause the device to act in in odd ways. Utilizing data modeling,engineers can define and enforce rules for the data that a system accepts. Someof the possible data modeling languages that can be used for configuration aredescribed below:

Chapter3. Concepts,TechniquesAndChallenges 15

3.5.2 SMIv2 ModelingLanguage

Withtheadvancementoftheinternet,computernetworkshavebecome morecomplexdaybydayandthereisneedto managenetworkresourcesina moreefficientway.SMIisthedata modelinglanguagethatisusedtowrite,defineaMIBmodule.TheSMIv2hasbeenutilizedforquitealongasstandardlanguagefordefining MIBmodules.

ThereareafewdownsideswhichlimittheuseofSNMPformanagingfuturenetworks. OneofreasonisthatSMIv2isnotsufficienttorepresenthierarchicalnetworkconfigurationdata. AnotherpointisthatSMIv2isbasic(notfeaturerich) modelinglanguagethatishardtobeutilizedfor modelingcomplex man-agementoperations[24]

3.5.3 YANG Data Modeling

The YANGdata modelinglanguagehasturnedouttobefamousamongnet-workingvendorsforvariousdatamodelingusecases.TheYANGdatamodelinglanguageisitselfadvantageousinthatitusesaC-likesyntaxtodemonstrateconfigurationandoperationaldatafornetworkdevices.Individualsandprofes-sionalswhoarecomfortablewithXML,XPath,andsomeessentialprogrammingcanrapidlyunderstandYANG’spowerfulsyntax.

AYANG moduleisbasicallyadocumentofYANG’sdata modeling. YANGModulecontainsthreesortsofstatements: module-headerstatements,revisionstatements,anddefinitionstatements. The moduleheaderstatementsportraythemoduleandgivedataaboutthemoduleitself,themoduleheaderstatementsgivedataaboutthehistoricalbackdropofthe module,andthedefinitionstate-mentsarethebodyofthemodulewherethedatamodelisdefined.

Amodulemightbeseparatedintosub-modulesinviewoftherequirementsofthemoduleproprietor.Theoutsideviewremainsthatofasinglemodule,payinglittlerespecttothepresenceorsizeofitssubmodules. YANGdefinesfourtypesofnodesfordatamodeling.IneachofthefollowingSubsections,nodetypealongwithitsexamplewillbeshownbelow:

Leaf NodesAleafnodecontainssimpledatalikeanintegerorastring.Ithasexactlyonevalueofaparticulartypeandnochildnodes.

leaf hostname{type string;description "Hostnamefor this system";


}

Listing3.1:LeafNodes.

Leaf-List NodesAleaf-listisasequenceofleafnodeswithexactlyonevalueofaparticulartypeperleaf.

leaf list domainsearch {type string;description "List of domain namesto search";

}

Listing3.2:Leaf-ListNodes

Container NodesAcontainernodeisusedtogrouprelatednodesinasubtree.Acontainerhasonlychildnodesandnovalue. Acontainer maycontainanynumberofchildnodesofanytype(includingleaf,lists,containers,andleaf-lists).

container system {containerlogin {

leaf message {type string;description

"Message given at start oflogin session";}

}}

Listing3.3:ContainerNodes

List NodesAlistdefinesasequenceoflistentries.Eachentryisastructureorarecordinstanceandisuniquelyidentifiedbythevaluesofitskeyleaf. Alistcandefinemultiplekeyleavesandmaycontainanynumberofchildnodesofanytype(includingleaf,lists,containersetc.)

list user {key "name";leaf name{

type string;}leaf full name{

type string;}leaf class {

type string;


}}

Listing 3.4: List Nodes

3.5.4 Capabilities of the YANG-Model

The following are the capabilities of YANG model:

• Reusable types and groupings

• Hierarchical configuration data models

• Extensibility through augmentation mechanisms

• Supports the definition of operations (RPCs)

• Formal constraints for configuration validation

• Data modularity through modules and submodules

• Versioning rules and development support. [25].

3.6 Separation Of ConcernsSeparation of Concerns (SoC) is one of the vital guidelines in software engineer-ing. Fundamental idea behind this principle is to separate different concernswithin the design or code to segments as far as possible. As a result, each seg-ment addresses a separate concern and it reduce complexity of design. Hence, itaccomplishes different designing metrics like robustness, adaptability, maintain-ability, and reusability. One conceivable answer for understanding a transparentSoc is to utilize the proxy design pattern. A proxy is a wrapper, which controlsthe entrance to the interface of any object and implements the same interface asthe wrapped object. By utilizing the proxy design pattern, it is conceivable toexpand or change the behavior of an object without changing the object itself.

Data structures can be designed by following Soc which is a typical designprinciple in computer science for isolating a programming code into small seg-ments. Consider as a basic case which demonstrates three sections of a similarclass that are characterized in three distinct files [26] namely bearhunting.rb,bear-eating.rb and bear-hunger.rb .


class beardef hunt#TODO: returnsomefoodendend

Listing3.5:bear-hunting

class beardef eat(food)raise ‘‘{food}is not edible!’’ unlessfood.respond_to?:nutrition_valuefood.nutrition_valueendend

Listing3.6:bear-eating.rb

class Bearattr_accessor:hungerdef monitor_hungerif @hunger>50then

@hunger =self.eat(self.hunt)endendend

Listing3.7:bear-hunger.rb

Sincenetworksliceisascalableelementanditcanbescaledtosuitnewservices.So,asmartapproachtoutilizethestrategywhichpermitstokeeptheconcernsseparated,isolatedandindependentfromeachotheraspossible.Hence-forth,separationofconcerndesignturnsouttobelesscomplex,simpletoperuseor maintainanditdiminishesthevolumeofcodeasaresultofgoodreusabilityofgivenconcerns. Separationofconcernslikewiseaddstoareductionofthecomplexityofdatastructuresasdiscussedinsection3.4

3.7 Service Orchestration

SDNtaskistoisolatethecontrolplaneanddataplaneandNFVaimstoorganizenetworkfunctionsandsoftwarerunningonanyopenstandards-basedhardware.Keepinginmindtheendgoaltodeliverbusinessincome,thereisaneedofserviceorchestrator. TheaimofServiceOrchestrationistoprovideautomation,provi-sioning,andinternetworkingofphysicalandvirtualresourcesinordertoenable


new service offering.

Figure 3.3: Service orchestration with NFV and SDN

Service orchestration is essentially coordination and course of action of thearrangement of services exposed as a single aggregate service. Service orches-tration works through the plan of sub-services in the area layer of applications.Since individual services are customized to communicate with other services asdemanded by the end user.

The business concurs that the combination of these abilities offers businessa way to agility and dynamic systems. To gain more benefit by virtualization,the convergence of each of the three technologies namely Orchestration, NFVand SDN must be tended to and on a carrier level which implies services canbe scaled up and down effectively with full reliability and security as shown inFig.3.3. These three technologies exploit cloud financial matters, what’s more,gives benefit mechanization so we can agilely address new market openings andpowerfully adjust existing services and administrations to best profit the business[27].

3.8 Advanced Remote Configuration Of VirtualNetwork Elements

Command Line Interface(CLI) and Simple Network Management Protocol (SNMP)are two approaches which were used for configuring devices and network in thepast. Initially, CLI scripting was the only way to deal with automated configu-ration changes to the network before the presentation of SNMP and NETCONF.One of the impediment is the absence of transaction management in this method-ology. Since configuring a device is a complex process which frequently includesvarious activities. For example in the event that one action fails other has to rollback, i.e. undo all previous actions.


In spite of the fact that SNMP was developed to be utilized for both monitor-ing and management (configuration changes) yet SNMP is generally utilized forfault and performance. SNMP does not provide a standard automatic discoveryprocess that finds the right MIB modules that the device is utilizing. This im-plies the discovery work must be performed by the users or operators and as it iscomplex, configuration management with SNMP has been surrendered. Anotherdownside of SNMP is that it utilizes UDP protocol where messages can easily belost or untracked and the lack standard security [28].

Also, SNMP is unable to retrieve complete device configurations So, that theycannot be compared with past setups or checked for consistency across devices.There is normally just fragmented scope of device features by means of the SNMPinterface and there is no clear differentiation between configuration data and op-erational data. These are a few of the complexities because of that SNMP andCLI are rarely used for configuring devices

In 2003, as popular vendors (Brocade Communications Systems Inc., CiscoFrameworks Inc., Juniper Networks Inc., Ericsson-LG, and Nokia Networks) fig-ured it out that SNMP was deficient for network configuration and that individualvendor CLIs cannot be programmed easily and require human translation. Withthe development of SDN/NFV, there is need of some powerful protocol to tradeCLI and SNMP for configuration management of programmable systems and net-works.

The Network Configuration Protocol (NETCONF) is network managementprotocol developed and distributed by IETF in Dec 2006. The NETCONF pro-tocol characterizes a basic machine with the help of that network device can bemanaged, configuration data can be recovered, and new configuration data canbe uploaded and controlled. The protocol enables the device to uncover a full,application programming interface (API). Applications can utilize this existingAPI to send and receive full and partial configuration data sets. NETCONF pro-tocol was designed to cover the inadequacies of existing conventions and protocolsfor configuration management. Some of the key differences between SNMP andNETCONF are summarized in table below.[29].

There has been a noteworthy rush from all of the major vendors to supportnetconf and yang and hence promote it as a component of open networks. Thevendors’ objective is to get human out of the loop of configuration managementbecause it is commonly estimated that up to 60% of configuration blunders hap-pen due to human mistyping error or interpreting things in the wrong mannerfrom print to their console. Among the supporters of YANG and NETCONF arebrocade communications systems inc. Cisco systems inc., juniper networks inc.Ericsson-lg , and nokia networks


SNMP NETCONFSNMP modifies single value pa-rameter at a time.

NETCONF modifies all or se-lected parameters with a singleprimitive operation.

The data modeling language doesnot support compound data typesand has unfriendly syntax.

A YANG module supports hier-archy based data for NETCONF-based operations.

SNMP does not provide a cleardistinction between configurationand state data i.e operationaldata and mechanism like routingprotocol.

NETCONF provides a distinctionbetween configuration and statedata.

SNMP perform well for retrievalof a small amount of data frommany devices but not suitable forretrieving large amounts of datadevices

NETCONF is equally suitable forretrieving both small amount ofdata and a large amount of datafrom many devices.

Table 3.1: Differences between SNMP and NETCONF[30]

Moving far from an equipment driven and proprietary network infrastruc-ture towards an open, standard based model will alter the way networks will bedesigned and implemented and worked. While deploying virtual services, theyconfront a completely new set of difficulties like testing, monitoring, and dealingwith those services. For example, virtual network elements don’t have any phys-ical interface and power switch option. In this way, if there arise some problem,network engineers need to deal these difficulties in a diverse way with the assis-tance of appropriate tools for diagnosing and eventually resolving specific issues[31].

3.9 Lean ConceptsIn the early 1990s, Toyota Production Systems has made the philosophy of Leanmanufacturing. The elimination of waste in a production system is referred asLean manufacturing. Hence, lean is centered on making or add value by reducingeverything else which add no kind of value to the system. The main goal of lean isto minimize time, reduce total costs and eliminate waste by improving the qualityof service brought to the customer.

Lean principles are being used in this case to reduce the waste of resources fac-


tor under pull/demand principle by reducing the request from the service providerto customer one time. So, the customer sends all the service specifications de-tails in their first encounter itself. Hence in this circumstance time is reduced.This kind of type of waste does not add any value to the customer and the ser-vice model. The five-step thought process for guiding the implementation of leantechniques [32] is easy to consider but not always easy to accomplish:

1. Identify value from the perspective of the end customer by product family.

2. Identify all the steps in the significance stream for each product family andreducing whenever possible those steps that do not create value.

3. Make the value-creating steps occur in tight sequence, therefore, the productwill flow smoothly toward the customer.

4. While flow is introduced, let customers pull value from the next upstreamactivity.

5. As value is specified, value streams are identified, wasted steps are removedand flow and pull are introduced, commence the procedure again and con-tinue it until a condition of perfection is achieved by which perfect value iscreated without having waste [33]

Chapter4

Methodologies

4.1 YANG Data Modeling

TheYANGdata modelinglanguagewasdevelopedbytheInternetEngineeringTaskForce(IETF)andpublishedasRFC6020inOctober2010.Itisjustadatamodelinglanguageusedtothe modelconfigurationaswellasfor manipulatingstatedatafortheNETCONFprotocol. YANGrepresentsdatastructureswithinanXMLtreeformat. TheYANGisprotocolindependentandcanbeconvertedintoanyencodingformateg. XMLorJSONprovidedthatitistobesupportedbynetworkconfigurationprotocols. YANGisadata modelinglanguagehavingseveralbuilt-indatatypeslike manyprogramminglanguages. Inaddition,itprovidesanopportunitytoobtainapplicationspecificdatatypesfromthebuilt-indatatypes.

AsampleexampleforYangmodelisshownbelow:

/∗∗ Copyright (c) 2014 Juniper Networks, Inc.∗ All rights reserved.∗/

modulerpc interface status {namespace "http://yang.juniper.net/examples/rpc cli";prefix rpc cli;

importjunos extension odl {prefixjunos odl;

}importjunos extension {

prefix junos;}

organization"Juniper Networks, Inc.";

23

Chapter4. Methodologies 24

description"Junos OS YANG modulefor RPCexample";

rpc get interface status {description "RPCexampleto retrieve interface status";

junos:command"showintf status" {junos:action execute {

junos:script "rpc interface status.py";}

}

input {leaf match {

description "Requestedinterface match condition";type string;

}}output {

containerinterface status info {container status info {

leaf interface {type string;description "Physicalinterface name";

}leaf status {

type string;description "Operational status";

}junos odl:formatinterface status info format {

junos odl:header "Physical Interface Status\n";junos odl:indent 5;junos odl:comma;junos odl:space;junos odl:line {

junos odl:field "interface";junos odl:field "status";

}}

}}

}}

Chapter 4. Methodologies 25

}Listing 4.1: Sample example of YANG Model

YANG data models involve modules or even sub modules and can characterizedesign and state information, warnings, and RPCs for use by NETCONF-basedoperations. A YANG module characterizes a data model through its data and theorganisms it in hierarchical order and imperatives on that data. Every module isuniquely identified by a namespace URL.

A module characterizes a solitary data model. In any case, a module canreference definitions in different modules and submodules by utilizing the importstatement to import external modules or include a statement to incorporate atleast one submodules. Also, a module can expand another data model by utilizingthe augment statement to characterize the situation of the new nodes in the datamodel chain of command and the when statement to characterize the conditionsunder which the new nodes are legitimate. A module utilizes the componentstatement to indicate parts of a module that are contingent and the deviationstatement to indicate whenever device’s implementation might deviate from theoriginal definition [34]

YANG data models utilizing a hierarchical and tree-based structure withnodes. YANG characterizes four node types Every node has a name and de-pending upon the node type, the node may either characterize a value or maycontain a set of other child nodes. Some common nodes types are summarized insection 3.5.3.

4.2 Network Element ConfigurationSNMP has been around for a long time and can also be used to configure variableon a device. But there are some issues with doing configuration with CLI likeadding VLAN requires quite a few steps, it seems that it is easier to log in toeach switch/router for configuration purposes. Let us take a case where one hasto configure some hundreds of switches/routers. So, it becomes unfeasible to doall these steps on such a large number of network devices [35]. Some similar issuesare discussed in section 3.8

Using Network Configuration Protocol (NETCONF) is a feature rich protocolwith features like installing, controlling, and deletion configuration of networkdevices. One of its key benefit over SNMP is that It utilizes a XML-based dataencoding for the configuration and protocol messages. The NETCONF operationsare acknowledged over a simple Remote Procedure Call (RPC) layer [36] Some key


benefits of using NETCONF over SNMP are listed in a tabular form in section 3.8

Figure 4.1: Basic NETCONF session

Fig.4.1.demonstrates a Basic NETCONF session. NETCONF enables a clientto find the set of protocols and conventions upheld by a server. These capabilitiestransferred amongst client and server permit the client to modify its behavior andto exploit the features upheld by the device. Extensible XML-based data encod-ing is utilized by NETCONF convention for both setup and protocol messages.A client encodes an RPC in XML and then sends it to a server utilizing a safesession. The server responds with an answer which is encoded in XML. The pro-tocol messages are exchanged on the top of a secure transport protocol[36]

In order to implement the network slice, there is need to deploy a network ele-ment which supports NETCONF protocol. For this purpose, Cisco cloud servicesrouter (CSR 1000v) is deployed and configured in cloud infrastructure. The CiscoIOS Router is not an emulation of any physical router or hardware component. Itis a virtual machine running 32-bit IOS XE software. This VM contains a solitaryroute processor with control plane feature and line card network interface. It is aportrayal of the IOS XE software and working framework, including reasonability,control plane highlights, routing and forwarding functionality.

4.3 Mapping Of Data StructuresA binding can be seen as a relationship between two entities. It might be eitherbetween name and memory location or between name and function. Typically,language bindings are characterized by a high-level language. Bindings charac-terize how objects are created, deleted and modified in an object-oriented pro-gramming language.


Pyang is a tool for validating YANG modules and transform YANG modulesinto other formats. It has several plugins. One of its plugin is PyangBind that canbe used for building data structures (class hierarchy) from a YANG data model.The subsequent classes can be directly connected with in Python, for example,creating new data instances by setting values in the Python class hierarchy, seri-alize populated objects into formats that can be stored, or sent to another system(e.g. a network element).

Development of PyangBind has been inspired by consuming the OpenConfigdata models and is proposed to be tested against these models. The Pythonclasses generation and serialization strategies are expected to give network op-erators a beginning stage for loading data instances from network components,controlling them, and sending them to a network device. PyangBind classes more-over have features which enable some additional techniques to be related to theclasses, so it can be used as a foundation of an Network Management System [37]

4.4 Lean IT ManagementLean is a design process to prevent error and invent value. It is the expansionof lean manufacturing and lean services to the arrangement and management ofinformation technology products and service. It focuses on the expulsion of wastefrom the system with regards to IT concerns in removing work that adds no valueto service.

4.4.1 Types of Wastes

The least difficult approach to describe waste is as “Something that adds noValue.” customers would not be glad to pay for any actions of offers that do notadd value to what they want or need. The waste in Lean Manufacturing can becharacterized into seven types and they are described below:

Transporttransport is the movement of materials starting with one area into another area.It is referred as a waste as it adds no value to the product.

InventoryInventory costs money. It can be crude material, work in advance or completedmerchandise everything has a cost and until the point that it is sold that cost isproducer’s cost and treated as a waste type.


MotionExcessive movements between workstations, machine developments from the be-ginning point to work point are generally cases of the misuse of Motion. Theseinefficient movements cost manufacturer time (waste) and eventually cause weighton employees and machines.

WaitingMore frequently employees spend time while sitting for an answer from anotheroffice in organizations, or sitting for a delivery from a provider or a technician tocome and fix a machine. In this way, a certain amount of time is wasted whilewaiting for things in our working lives.

Over-ProcessingThis kind of waste incorporates wrong strategies, oversize hardware, attemptingto resilience that is too tight, perform processes that are not required by thecustomer etc. These things cost time and money and should be prevented.

OverproductionThe misuse of overproduction is making excessively or too soon. This is generallya direct result of working with oversize batches, long lead times, or even poorsupplier relations.

DefectsDefects are not generally the least demanding to distinguish before hearing fromclients. Quality mistakes that reason surrenders constantly cost much more thanmaker anticipate. Each damaged thing requires modification or even substitutionin some cases as a result, assets and materials are wasted and increases the riskof losing customers [38]

4.4.2 Optimization Aims

• Reduction in lead time for the delivery of products and services.

• Increase in productivity.

• Reduction of stock levels and work in process.

• Lightened report administration.

• Reduced utilization of assets utilized as a part of the production, energyetc.) [39].


4.4.3 Mapping of Lean Wastes to Optimization Aims

Lean principles that aim to eliminate the waste in a slice- based service are:

• Value: Just oversee profitable data, that must be overseen and data thatunderpins the center business exercises. Keep in mind clients advantagefrom the design and just utilize it if it offers direct value or they comprehendthe indirect value i.e. for another department.

• Value stream: Make sure that the arrangement of procedures and ex-ercises that convey information are mapped. This incorporates processesthat help the capture, portrayal, exchange, organization, retrieval , andvisualization of information.

• Flow: Information ought to be accessible ongoing when it is produced orobtained. Limit duplication of data inside the organization, departments,and customers and suppliers.

• Pull: information and extra usefulness should just be conveyed as it isrequested. To encourage pull, the interfaces, methodology , and proceduresneed to be consistent across the organization.

• Continuous improvement: Review infrastructures and procedures onregular basis. Try to recall data frameworks, business procedures, and pro-cedures that help products and services change [40].

Chapter 5Results And Analysis

Operators design and prepare a customized network slice for their clients (whichmight be either customer organizations or end consumers) as a service. These op-erators then hand over the network slice to the consumer organization who mayclaim both the network and terminals support, for example, video surveillancenetwork, for security companies. To outline it further, we can take a parentalcontrol service as an example to further describe NSaaS. As a rule, a parentalcontrol slice offers its clients to setup service on their Wi-Fi router to ensure thewhole home system and every cell phone. SafeDNS Agent for Windows is anotherconceivable approach to secure individual PCs. This program set the service au-tomatically on client PC and figure out which sites are suitable for children [35].Deployment of such service often includes different steps keeping in mind the endgoal to be effective.

5.1 Comprehensive Deployment AndManagementWorkflow

Figure 5.1: Workflow in service deployment

The Fig.5.1 illustrate the stages of the workflow involved in the deploymentof network service. At first, operators design a network slice for a particular ser-vice model they work upon which is referred as an industrial template. There isa scope of reducing additional costs at the infrastructure level. There are Lean

30

Chapter 5. Results And Analysis 31

concepts that can be used for designing of the model, data structure generation,and templating. But, this service model still needs the inputs such as SLA whichare some official commitments between the service provider and clients. It is anagreement between client and service provider that define the type of services tobe provided and standards they meet. In order to setup the additional featuresthe providers needs to price up the service in terms of the features that serviceprovider has committed for along with few additional features that make up themarket.

The second stage is release service manager from the marketing departmentto make the introduction and use case studies of the network service to awarecustomers about the value of services they offer. Then comes internal reviewprocess like the service can be released into the market.

In the third stage, customer order the network slice as a service and inputrequirements to the vertical template, such as slice coverage, capacity, and SLA.This stage has inputs from the customer as lean focuses on what customer is readyto pay for and cost value functions are well-defined here. In the fourth stage,the network slice service is deployed and executed, while both the operator andcustomer are able to monitor the status of the connections and service. Finally, ifthere is no demand for existing network slice in the marketplace, operators woulddispose it and end its life cycle. Hence, lean concepts play an important roleto have a continuous improvement and feedback from customers to update theservice specifications according to market existing service requirements.

In this thesis, data model for network slice is parsed to determine the ap-propriate data structure. Data structures are built in such a way that resourcesare not over provisioned to provide required network functions. Also, there isneed to keep in view the orchestration plans because NS can be automated andprovisioned as needed. Aim of lean management concept here is to improve theefficiency of service provisioning and finally service delivery performance featuressuch as time to set up a network slice. Lean does not aim here at data transportare hence does not take into consideration factors like packet delay, throughputetc.

5.2 Analysis And Evaluation ConceptThe Cisco CSR 1000v is a cloud-based virtual router which is deployed on avirtual machine server hardware. It supports a set of Cisco IOS XE softwarefeatures like security and switching on a virtualization platform. Its key benefitis being Hardware independence as it runs on a virtual machine on a hypervisor.It also enables sharing of resources so they can be shared among VMs running on


a hypervisor Cisco CSR 1000v is flexible to move VM hosting Cisco CSR 1000vfrom a server to another without any problem.

Figure 5.2: Configuration of Cisco CSR 1000v in AWS

Fig.5.2. shows the configuration of Cisco CSR 1000v in an AWS cloud en-vironment. AWS has several benefits like it provides logically isolated networkswith their own IP range, routes, security groups, and network access control lists.In order to deploy Cisco CSR, we used Cisco CSR 1000V image from AWS mar-ketplace.

Fig. 5.3. shows the creation of a pair key for accessing the CSR 1000v from

Figure 5.3: Creation of a Key pair.


our local workstation. Although it is possible to log in to a remote system us-ing passwords. Using key-based authentication is recommended for more security.

Figure 5.4: Configuration on Cisco CSR Router step1

In order to SSH a Cisco CSR, SSH needs to be enabled on both remote hostand clients. SSH is a protocol which is commonly used to securely logging intoremote systems. SSH works by connecting a client program to an SSH server.Following commands are needed for enabling SSH and NETCONF access on theCisco CSR router as shown in Fig.5.4.

Figure 5.5: Configuration on Cisco CSR Router step2

Fig.5.5. shows the connection to CSR router using SSH command. When weattempt to SSH remote host using a key-pair, the server authenticates the clientworkstation with the private key and sends the appropriate response back to theworkstation.

Next step is to design a network services using YANG model. The model isdescribed below.

/∗∗∗ NAMESPACE / PREFIX DEFINITION ∗∗∗/module ba s i c {

namespace "http :// bth . se " ;p r e f i x " conf " ;

Chapter5. ResultsAndAnalysis 34

importietf inet types {prefix inet;}organization "BTH";contact "Asample yang model by Nayyar & Phani";description"The modulefor creating basic network topology of

networking devices.";revision 2017 06 19 {description "Initial revision.";}

/∗∗∗CONFIGURATION DESCRIPTION ∗∗∗//∗∗∗ Router 1∗∗∗/

list link {key "link id";container router 1{

leaf router 1 ip{typeinet:ip address;}leaf router 1 time2complete

{type uint64;

}leaf router 1 dependency{

type boolean;}leaf router 1 state{type boolean;default false;}

}

/∗∗∗ Router 2∗∗∗/container router 2{

leaf router 2 ip{

typeinet:ip address;}


leaf router 2 time2complete{

type uint64;}leaf router 2 dependency{

type boolean;}leaf router 2 state{

type boolean;default false;}

}

/∗∗∗ Router 3∗∗∗/container router 3{

leaf router 3 ip{

typeinet:ip address;}leaf router 3 time2complete{

type uint64;}leaf router 3 dependency{

type boolean;}leaf router 3 state{

type boolean;default false;}

}leaf link id {type string;} }

}

Listing5.1: DesignofYANG ModelforService

ThescriptofToolforpushingconfigurationisdescribedbelow:

#import providers, services, and models


from ydk.servicesimport CRUDServicefrom ydk.providersimport NetconfServiceProviderimport bindingimport netaddr

importJSON

#NETCONFsessionprovider = NetconfServiceProvider (address="54.76.238.182",

port=830,username="admin",

password="admin",protocol="ssh")

config =json.loads(open(’default.json’).read())

# For Router 1myobj1=binding.yc_router_1_basic__link_router_1()myobj1._set_router_1_ip(config[’ip 1’])myobj1._set_router_1_time2complete(config["time2complete 1"])print "Router 1 Configuration"print myobj1._get_router_1_ip()print "\n"time1= myobj1._get_router_1_time2complete()

# For Router 2myobj2=binding.yc_router_2_basic__link_router_2()myobj2._set_router_2_ip(config[’ip 2’])myobj2._set_router_2_time2complete(config["time2complete 2"])myobj2._set_router_2_dependency(config["dependency 2"])print "Router 2 Configuration"print myobj2._get_router_2_ip()print "\n"time2= myobj2._get_router_2_time2complete()dep= myobj2._get_router_2_dependency()

# For Router 3myobj3=binding.yc_router_3_basic__link_router_3()myobj3._set_router_3_ip(config[’ip 3’])myobj3._set_router_3_time2complete(config["time2complete 3"])myobj3._set_router_3_dependency(config["dependency 3"])print "Router 3 Configuration"print myobj3._get_router_3_ip()print "\n"


time3= myobj3 . _get_router_3_time2complete ( )Listing 5.2: Script of Tool for pushing configuration

5.3 Performance Results

5.3.1 Initial Quantification of Improvements by applyingLean Concepts

For a given certain service chain with uncertainty, we consider two use cases. Incase 1, the service/router is dependent. i.e. there may be some services which arepart of a network slice and they need to be configured before the other services.while in case 2, the service/router is independent and all services which are partof a network slice can be configured independently regardless of other services innetwork slice.

Figure 5.6: Configuration of network element for case 1

Figure 5.7: Configuration of network element for case 2


5.3.2 Optimization Criteria

These are the some wastes that can be interpreted for optimization criteria ofslice-based service deployment from the manufacturing industry.

• Resource Over-provisioning: This is the waste which relates to allo-cating more resources like data storage or bandwidth thna required. Thiswaste type is interpreted as over production in manufacturing industry.

• Waiting Time For A Service: This means waiting time until a service isprovisioned. This waste type is interpreted as waiting time in manufacturingindustry.

In this thesis, Lean aims at increases the efficiency of service provisioning.For example, in case 2 (parallel configuration of network elements) it can beseen that waiting time while provisioning a service can be significantly reducedby applying lean principles. In cloud environment, over provisioning results inincreases power, cooling and management costs. Same is the case for NS, thereis no need to provide more resources than needed for that service. Resource overprovisioning in NS is minimized while building data structures and orchestrationplans.

Chapter 6Conclusion And Future Work

6.1 Summary

Figure 6.1: Architecture of Thesis

The Fig.6.1 gives you a brief idea of our thesis work. The config file holds theconfiguration which we want to push into network element like IP address, stateof routers etc. Ydk-gen is a pyang developer tool is used to generate bindingsfrom the configuration file (Yang). The bindings script validates the configura-tion according to the defined data structures that we gave from the config file. Atool is implemented whose front-end read specifications from the file and back-end establish a connection to the network element to configure network elementsusing the defined data structures.

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Chapter 6. Conclusion And Future Work 40

Later on an algorithm was implemented for simulating the deployment whichaddresses the lean optimization aims. It uses customized fields like states, thetime to complete and dependencies of network elements with a set of values fromthe config file. Finally, the simulated is done in accordance with time to complete,dependencies and waiting time.

6.2 Answers to Research QuestionsRQ1. What are feasible, appropriate, or optimal data structures andorchestration plans for service deployment in future networks for slice-based services?

By using separation of concerns principle, optimized data structures are gener-ated which are less complex and later their features and behavior can be groupedinto manageable parts. It is important as service deployment has specific pur-poses and business to take care of in future networks. The answer to this researchquestion is further discussed in section 5.1.

RQ2. How can one instantiate the data structures with appropriatecontent such that it can be used for testing and configuration of net-work elements?

The data structures dump a dictionary representation of the object for test-ing and configuring purposes. To achieve this, the data structures are serializedinto a JSON format and these data instances for interact with network elementsfor testing and configuration purposes. The further explanation to this researchquestion is provided in section 5.2

RQ3. How can we transfer the wastes of lean management into op-timization criteria for slice-based future network services?

Out of seven waste types discussed in section 4.4.1, waiting time and over pro-duction from manufacturing system are easy to identify and interpret in serviceindustry for services like network slice. For optimization criteria, overproductionof products and goods can be interpreted as over-provisioning of resources todesign and instantiate Network slice. In the same way, waiting time from pro-duction industry can be interpreted as waiting time to setup a service. Furtherdetail regarding optimization criteria for slice-based future networks is discussedin section 5.3.2.

Chapter 6. Conclusion And Future Work 41

6.3 Future Work• More entities may be defined in data models for services. For example, SDN

controller allows packet inspection feature in network elements and it maybe possible to give different access rights for some users so that traffic flowinspection cannot be visible or accessible to all users.

• A big object-oriented file is used in this thesis accordance with data mod-eling. Next step could be to find out a way to split it into smaller objectsand thus making a large number of the object-oriented file. By doing so,they become more maintainable, more reusable, etc.

• Moreover, there is need to include more use cases for a comprehensive sim-ulation. Right now, only use case of waiting time is considered. Resourceefficiency can also be related in future. Learn parameters can be extendedto relate them with network quality parameters as well.

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