DESIGN, DEPLOYMENT AND SW VALIDATIONTO VIRTUALIZE A MOBILE DATA CORE
NETWORK TO USE 5G TECHNOLOGY INVODAFONE
MASTER THESIS
BY
ANDREA VALLEJO PUIGVERT
JULY 8, 2018
SUPERVISORS
CÉSAR BENAVENTE
FINI IRLES
MARTA DE PABLOS
UNIVERSIDAD POLITECNICA DE MADRID
INTERNET TECHNOLOGY AND ARCHITECTURE
EIT DIGITAL MASTER SCHOOL
ACKNOWLEDGEMENTS
I would particularly like to single out my supervisor and mentor Marta de Pablos, who alwayswas willing to help me not only with her patient, dedication, enthusiasm, and immenseknowledge but also with her motivating speeches which have helped me overcome anydifficulty. I could not have imagined having a better advisor and mentor for this master thesis.
I would like to sincerely thank my internship supervisor Fini Irles of the Data Core depart-ment at Vodafone, for making this thesis possible and for her valuable support and guidanceduring my internship with her.
I also like to thank all the Vodafone, Altran and Huawei experts who were involved in thisproject and who helped me with their advice and explanations: Mario Pérez, Sergio Carretero,María Jesús Jiménez, Raquel Perdiguero, Luisfer Bartolomé, César Antón, Fran Pariente, JuanManuel Temprado, Jorge Salas, Patricia Sánchez, Jesús Rodríguez, and Ángel Báez. Withouttheir passionate participation and input, this project would not have been successfully made.
I would also like to acknowledge César Benavente of the Department of Signal Theory andCommunications at the Polytechnic University of Madrid for having his office door alwaysopen whenever I had a question about how to focus my research. Furthermore, I am gratefullyindebted to him for his very valuable comments on this thesis.
And last but not least, I must express my very profound gratitude to my parents and to mysister for providing me with unfailing support and continuous encouragement throughoutmy years of study and through the process of researching and writing this thesis. This accom-plishment would not have been possible without them.
The world of telecommunications is constantly changing. Customers expectations are con-stantly growing, pushing the market to adapt in order to meet new customers needs. In thisenvironment, new business models are created mainly focused on boosting data transfer,turning into an aggressive growth of data in mobile networks. In fact, only during last year,data consumption increased by 70%. On the other hand, customers want to enjoy this dataat any moment, in any place, and through a real-time experience. Due to this digital revolu-tion, mobile communication is now one of the key essential services that society needs anddemands.
Within this framework, all mobile phone operators and in particular Vodafone Spainare facing a great challenge. Vodafone needs to cope with this new scenario, increasing itsnetwork capacity and its speed in data transfer. However, expanding the legacy networkwithout increasing tariffs is no longer profitable. It is time to introduce new technologiessuitable for this huge and constant data growth. Replacing the old bare metal network with anew virtualized one is something that becomes necessary for Vodafone in order to continuebeing a leading company in its sector. The advantages of virtualization will bring economicbenefits for the company and will help Vodafone to be prepared for this new paradigmchange.
On top of this, Vodafone wants to be the leader in innovation and it is constantly develop-ing new technologies that will help to create new products and services for this new digitalsociety. The new virtualized network is the perfect scenario to take the first steps beyondthe implementation of the new 5G mobile generation in Spain. The digital transformation isalready changing the industry and society and Vodafone is already working to change ourdaily life.
The future is exciting, are you
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1
INTRODUCTION
Since the market and the needs of people are constantly changing, mobile phone operatorshave many new challenges to face, as well as new opportunities to take advantage of.
One of the main changes that the market is experiencing, is the growing penetrationof smartphones. This growth is resulting in a higher demand for mobile data. Users aredemanding better and faster quality services at any time and in any place.
In this context, new Over the Top (OTT)s are trying to break into the market to offer newapplications and services to customers.
This situation has created more competitiveness among them and has brought newinnovative ideas and business models. Nowadays, OTTs like Netflix or Amazon can generaterevenues from their services faster than in the past. And this is thanks to the fact that they aregrowing and changing continuously, following the consumer demand.
In addition, OTTs are also responsible for causing an exponential increase in data con-sumption, and more specifically the ones that offer high-definition video. Therefore, for theoptimal functioning of all these applications and services, new and better data core networkresources are required.
What does this mean for mobile operators? if they want to support these services andapplications, they should move fast to adapt all their infrastructures, according to the newrequirements imposed by consumers and OTTs. This is why Vodafone decided to renovate itsdata core network by virtualizing it.
However, these are not the only reasons that are pushing mobile operators to change.There are also other factors such as the new competitors that are emerging in the marketthrough the Mobile Virtual Network Operator (MVNO). This new concept of operators isshaking the market by decreasing the prices of their services. This fact is impacting all theconsolidated operators in the Spanish market. In fact, the most impacted one in the past fewmonths is Vodafone, losing a large customer base due to the high customer churn rate.
Virtualization is not only the enabler for this quick adaptation but also a new source ofrevenues because the user is allowed to consume more. So, the higher the consumption, thegreater the benefit. Furthermore, virtualization allows the implementation of new networkarchitectures, such as MEC or network slicing, that are the main enablers for new subscriptionservices key to monetizing customers relationships.
Vodafone wants to stop being just the data access pipe for customers to become also a
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CHAPTER 1. INTRODUCTION
company that offers added value services to its users through the new technologies.In order to virtualize the network, some tools are needed. NFV is a method which allows
virtual instances of physical networks to be separated in virtual resources. These resourcescan work in independent sections or combining them with the objective of providing networkservices. The aim of network virtualization is to improve the productivity and efficiency oflegacy networks by performing tasks automatically. Moreover, this kind of networks can bemanaged in a central way through a single physical site.
SDN is a set of techniques whose goal is to facilitate the implementation of networkservices in a deterministic, scalable and dynamic way. Thanks to SDN, it is possible toavoid the network administrator to manage such services at a low level, improving networkperformance and monitoring.
NFV and SDN are the best allies to quickly adapt the network to the different changessince they can virtualize the network functions of the traditional network. This is madeby dynamically adapting, arranging and distributing the available resources according tothe demand. Hence, any modification is fast and easy, reducing costs and improving thetime-to-market. In addition, using virtualization over the network brings the opportunity toobtain new revenues:
- On one hand, SDN allows the network to direct the data traffic flows, without the needto rely on the Hardware (HW). Therefore, all decisions are taken by SW and there is noneed to provision or configure the network in a manual way. This brings benefits tothe network, such as: Increase automation, enhance security, reduce operating costs,cloud-ready infrastructure.
- On the other hand, NFV can modify the services and features of the applications ondemand to better suit the needs of the consumers. In addition, it also works withoutneeding to make any changes in the HW since all the modifications are made on the SW.Another advantage of NFV is that it is possible to rapidly scale services and applicationsup or down and place it wherever is needed over the network. For instance, centralizing,distributing, or placing it closer to the consumer by using MEC, or creating layers withspecific functionalities according to each service or application by using Slicing.
As a conclusion, thanks to NFV and SDN, there is no need to have one HW per function,as it was before since the functions are virtualized. As a result, there is a reduction in theCapital Expenditures (CAPEX) and Operating Expenses (OPEX) of the company. Moreover,thanks to these two tools, the network can not only be virtualized but also facilitates thesupport of future 5G technologies.
Furthermore, virtualization is the first step that brings closer the reality of 5G in thedata core networks by using Non Stand-Alone (NSA) architectures. Once this step will bedone, the following phases will consist of adapting the data core to the new architecture,called Stand-Alone (SA), standardized by the Third Generation Partnership Project (3GPP)organization. 5G will brings more innovation and new business ideas based on low latencyapplications. Furthermore, the areas of use are very broad, for instance: health and wellbeing,automotive and mobility, security and surveillance, industry and manufacturing, energy,smart city, education, learning, or entertainment, among others.
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CHAPTER 1. INTRODUCTION
However, not all are advantages in the virtualized environment since there is a longjourney to get there and a lot of challenges to face. First of all, there are new NetworkElement (NE)s that need to be developed, following the already established 3GPP standard.Another challenge is the adaptation to services on-demand, which will need to be a dynamicand policy-based. Besides, for managing all this, it is necessary to integrate an infrastructurewith a real-time analytics.
In order to implement all this, it is necessary to carry out several tasks, such as: Integra-tion and dimensioning, connectivity desing, NEs instalations, NEs configuration, SW , andproduction deployment. All these steps need to be done fast, always taking into account thetime-to-market.
The objective of this thesis is to show the reader all the necessary steps to virtualize thedata core network of Vodafone. To do this, all activities that were carried out will be explained,covering business and technical areas.
Therefore, this master thesis is mainly divided into two parts:
- The first part has a more business approach. Here, there will be explained the prob-lems that Vodafone had to face, and for which Vodafone had to make the decision tomodernize its network. It will also expose in detail its value proposition, detailing theservices that Vodafone will offer to their clients.
Besides, the results of the market studies will be indicated, showing which are thedirect competitors of Vodafone, as well as its customer segmentation. Additionally,the Vodafone’s go-to-market strategy will be exposed, on which the company wants toattract more customers.
Finally, the management part of the project will be detailed. The intention of thissection is to give the reader a general view of how a project of this type can be structuredin scope, time and cost.
- The second part of the thesis, is more focused on the technical approach. It will startwith the legacy network overview and it will cover all the steps needed to virtualize thenetwork, deep diving on the NEs design and implementation. Specifically, this thesiswill be mainly focused on the following platforms: Virtual Unified Packet Gateway(vUGW) and Virtual Unified Serving Node (vUSN), which could be considered the twomost important nodes to ensure the proper functioning of the network. Both platformsare provided by Huawei company since Vodafone has opted to renew its networkwith products of this company. Additionally, the NEs Centralized Gateway (CGW) andDistributed Gateway (DGW)which conforms the vUGW in 5G networks (NSA), will beintroduced to the reader.
Therefore, all the technical activities involved in carrying out this project will be ex-plained in detail. For instance, Integration and dimensioning, connectivity desing, NEsinstalations, NEs configuration, and SW validation.
Finally, the results of the tests carried out in the platforms vUSN, vUGW, CGW, andDGW will be exposed and commented.
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CHAPTER 1. INTRODUCTION
1.1 THESIS OUTLINE
This thesis is structured in six chapters, as follows:
• Chapter 1: First chapter is the introduction, where is a summary of the subject of thisthesis, as well as the motivations.
• Chapter 2: Second chapter presents the business plan of this project on virtualizationof the network and 5G. The company description, value proposition, goals, marketanalysis, strategy, are shown in this chapter.
• Chapter 3: Third chapter introduces the project planning, with all the schedules andactivities performed during the project, as well as the and budget used.
• Chapter 4: This chapter gives an overview of the technical background. Here, topicslike techniques for virtualization, virtualized network architecture, and 5G networksare explained.
• Chapter 5: Chapter five has the technical deployment description. Furthermore, thischapter will give details about the virtual infrastructures used during the deploymentof the virtual network. Besides, the connectivity design will be discussed. Moreover,the procedure used to install and configure all the platforms is shown, as well as theuse cases, SW Validation and its results.
• Chapter 6: The final chapter gathers the conclusions that have been reached aftercarrying out this thesis, as well as possible future works.
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2
BUSINESSS PLAN
This chapter gathers all the parts that make up the business plan for this project. It is dividedinto seven parts:
First, a brief summary of the business plan will be presented to have an overview of thechapter.
Second, a company description will be provided to know what was the beginning ofVodafone, and how it has managed to be one of the best mobile operators in the world.
Furthermore, in the third section, the Business Drivers section is presented. The idea is toprovide the reader with all the reasons why Vodafone has decided to modernize its data corenetwork, and what they want to achieve with it.
The value proposition is the fourth part of this chapter. Here, it is explained why thecustomer should buy the products and services that Vodafone provides with its new data corenetwork.
In the fifth section, there are two studies which analyze the market status: One to deepdive into the main competitors and another to be aware of the customer segmentation.
Following, it is exposed the main steps necessary to validate the services and productsoffered by Vodafone. This section will be more developed in Chapter 5, where all the detailsof how this implementation was made are presented.
Finally, the seventh section gathers information about which is the Vodafone’s pricingstrategy, as well as its promotion strategy to sell their products and services.
2.1 EXECUTIVE SUMMARY
During the last years, the situation of the mobile telephony market has changed radically.On one hand, Vodafone has lost around 243,900 users because of very aggressive marketingcampaigns carried out by Orange, and also due to the low prices strategy of MásMóvil. Thisplaces Vodafone as the third mobile phone company in Spain behind Movistar and Orange.On the other hand, there is more and more data consumption and more applications thatdemand high performance from operators’ data core networks.
For those reasons, Vodafone has decided to bet on virtualizing its data network in order tobe able to increase resilient capabilities and network performance, improving user experienceand increasing profitability, that in the end comes into loyalty.
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The main competitors of Vodafone are Movistar, Orange and MásMóvil but currentlymain one is MásMóvil due to its powerful price campaign that is increasingly, attracting usersof other operators.
The new services that can be implemented thanks to the Vodafone data core networkvirtualization, are mainly focused on people from Europe, who are individual clients between18 to 30 year old, and who are located in urban and semi-urban areas.
Moreover, the pricing strategy will be based on the quality of service offered. The higherthe quality of the service, the higher the pricing. However, these prices will be adapt depend-ing also on the competitors pricing strategy.
All these will be promoted by an aggressive campaign, where all the products and serviceswill be advertised through as many channels as possible, like TV, radio, press, and socialmedia, among others.
2.2 COMPANY DESCRIPTION
Vodafone is a telecommunications operator with headquarters in Newbury, United Kingdom.It was initially known as Racal Telecom in 1983, but in 1991 it was finally founded as Vodafone.
Vodafone has subsidiaries spread all over the world, and all these countries are part ofthe association called Vodafone Group. It provides mobile services in 26 countries, fixedbroadband services in 17 countries and it has agreements with another 49 [34].
The economic benefits and the number of customers of Vodafone have consolidated thecompany as one of the most important telecommunication operators in the word. In fact, atthe end of June 2017, Vodafone had more than 518 million mobile telephony customers, aswell as more than 15 million fixed broadband customers. These numbers place Vodafone asthe second bigger telecommunications operator in the world.
One of the fourth big markets of Vodafone Group is Spain. Vodafone started there bybuying Airtel’s shares in 1999, until taking control of the entire company. In addition, withthe intention of continuing to grow, in 2014 Vodafone Spain bought the Corporative GroupONO, S.A., and went to the market with its first MVNO called Lowi.
Nowadays, Vodafone Spain has about the 25% of the market share, with large numbersof consumers in the different services offered: 14.4 million mobile telephony customers,7,5 million in 4G services, 3,2 million fixed broadband, 2,3 fibre, 1,3 Vodafone TV, and 2,3Vodafone ONE. Figure 2.1 shows what has been the growth of the company in terms ofcustomers, from 2014 to 2017. All these numbers, place Vodafone Spain in the third position,behind Movistar and Orange [37], [27].
The successes achieved by Vodafone Group and Vodafone Spain are the keys to consoli-date this company as one of the most important in Spain. These achievements can be dividedinto several major milestones, where Figure 2.2 holds the most significant ones.
All this could not have been achieved without having the best network infrastructure.Actually, Vodafone Spain is able to provide Global System for Mobile comunications (GSM)(2G) services at 900 and 1800 MHz, Universal Mobile Telecommunications System (UMTS)(3G) at 900 and 2100 MHz and Long Term Evolution (LTE) (4G) at 800, 1800, 2100 and2600 MHz. Besides, the data core network of 4G is compatible with 4G+ which provides
Figure 2.2: Milestones and Launches: Vodafone in Spain (1994-2016) [34].
a download high speed. Moreover, Vodafone’s network can cover around the 94% of theSpanish population with its coverage, being the best mobile operator in terms of coverage.In addition, it was selected as the winner of the P3 testing carry out in Spain [3]. For moreinformation, see Subsection 2.5.1.
2.3 BUSINESS DRIVERS
The objective of this project is to change the Vodafone’s data core network to adapt and coverthe new needs of the market and the users. Furthermore, the other main objective is to obtainnew revenues stream thanks to the use of new technologies such as virtualization and 5G.
Nowadays, people spend around 30 minutes per day watching videos on mobile devices,when in 2013 it was just 10 minutes every day. Besides, people also spend a lot of timewith the phone to send messages to their friends. In fact, there are two main messagingapplications: WhatsApp, Facebook Messenger, which have almost one billion monthly activeusers. In addition, around 60% of all payment transactions are now made digital. Moreover,it is estimated that there are more than 30 million Amazon devices in the homes of users,compared to 10 million at the end of 2016.
All these show that there is an exponential increase in the consumption of data in the lasttwo years, and more especially since the appearance of applications such as Instargram, or
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platforms such as Netflix.To have a broader vision of the consumption that can be generated daily, Figure 2.3 has
represented the most important OTTs currently and their Gbps per day consumed. Theimage shows that the applications that have a higher data consumption per day are YouTubeand Instagram with their "Instagram Stories".
Youtube has been consolidated as favourite channel of users to watch videos. But Insta-gram follows it closely, and it is expected to increase its numbers. The third application ofvideo consumption is Netflix, although it still has enough to reach the other two previouslymentioned. Video and audio download applications, such as BitTorrent, are losing strength.This is because more and more multimedia content is consumed through applications, andnot by downloading files directly.
Figure 2.3: Top Apps – Daily Data Volume (GB/Day) [25].
Although the data consumption today is quite high, it is expected to increase even more.In fact, this traffic forecast is another factor for which Vodafone has decided to renew itsnetwork. In order to face this new situation, capacity, and data upload and download speedswill need to improve.
Below, in Figure 2.4 is the traffic forecast of data that Vodafone expects to have in thecoming months. In black, the demand that would be presented without considering theincrease in data consumption is represented, while red line represents the new demand.It should be noted that there is a considerable peak in the month of August, and morespecifically from 15th of August, where the traffic forecast peak is 347 Gbps. This is due to thefact that as of that date there is a greater consumption of data for the summer holidays. Inthis month an increase of 25% is expected, and 7% in the following months.
The solution found by Vodafone to deal with these new situation, is virtualization. Thanksto the use of virtualization, it is expected to cover this increase in data consumption and pro-vide enough capacity to face unforeseen large spikes of data. Figure 2.5 has a representationof network capacity evolution. The traffic forecast expected is the line in red, and the resilientcapacity in the future month, the line in blue. As it is possible to see, the resilient capacity ismore than enough to cover these needs.
The virtualization of Vodafone network will be done gradually. Lines carrying more datatraffic will be virtualized first. After, it will be virtualized the rest of the lines. Figure 2.6 has
represented how the scenario will be for March 2019, where a 45% of the network will bevirtualized using Virtual Network Functions (VNF). In order to see more information aboutwhat is virtualization, go to Section 4, where there are explained the main concepts of thissolution as well as some tools which are needed in order to implement it.
Figure 2.5: Traffic forecast vs. Capability[25].
Figure 2.6: Forecast: VNF and Legacy in2019 [25].
2.4 VALUE PROPOSITION
The main objective of Vodafone is to connect people worldwide, allowing the users to en-joy communications across different mediums convenient & secure. Therefore, the clientexperience is one of the keys within the value proposition.
To achieve this, Vodafone offers an improvement in its data core network, with whichit manages to improve the resilient capacity of the network, as well as its performance.Therefore, it will be able to provide higher speed data transmission, and greater bandwidth,which will make the data user much faster than they have ever been.
With this, Vodafone aims to surpass all its competitors and offer the user the opportunity
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to use the best services from one of the best networks in the world. Vodafone also aims toreach more and more consumers, and therefore expand its market.
2.5 MARKET ANALYSIS
2.5.1 COMPETITORS
There are two types of competitors among mobile operators: Operators which have their ownnetwork called Mobile Network Operator (MNO), and operators called MVNO. The MVNOdoes not have its own infrastructure, so it uses the network of others in order to providecoverage to their customers.
In the Spanish market, the operators with their own network are Vodafone, Movistar,Orange and Yoigo (recently adquired by MásMóvil). They have their own infrastructure andbecause of this reason, they are able to provide more and better services than the MVNO.However, the MVNO are in general cheaper than the MNO and they have been very wellreceived by users. This is why it has increased the number of this kind of operators in thelast years. These companies have been so successful that some MNO have created their ownlow-cost brands in order to compete with the MVNO. For instance, Vodafone has had createdLowi, which offers rates at lower prices. However, other mobile operators instead to createother brands, they have bought companies that already existed. Figure 2.7 has a map of howis the current situation of the relationships that exist between mobile operators in Spain.
Figure 2.7: Map of the main unions between mobile telephony operators in Spain.
The study of the competitors will be carried out, taking into account the four mainoperators with its own infrastructure, and the main competitor of the virtual operators. Theseare: Vodafone, Movistar, Orange and MásMóvil.
In this first part, there is a more business approach where the situation in the marketof all the operators will be evaluated. However, the second part will have a more technical
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approach, where the technical features of each company will be compared.The following Figure 2.8, shows the market share of the main mobile telephony operators
in Spain in December 2017. These statistics are related to the number of lines registered byeach operator. The three main operators are Movistar, Orange and Vodafone, respectively,which have 80% of the total market. The rest of the market is for the set formed by the MVNO.
Figure 2.8: Market share of mobile telephone companies in Spain (December 2017) [29].
As seen in the image, Movistar is in the lead, followed closely by Orange in the secondposition, and Vodafone in the third position with a 24.9% share. Last year, Vodafone occupiedthe second position in this ranking, so it can be said that the results have worsened for them.It should also be noted the percentage of shares that MásMóvil has achieved in less than ayear.
These results are mainly due to two factors. The first is the appearance of the operatorMásMóvil, which has made offers at a very low price, causing users migrations from othercompanies to MásMóvil. Secondly, there are the marketing campaigns carried out during 2017by Orange. These campaigns were specially prepared to capture Vodafone users. Therefore,Vodafone has experienced large amounts of portability in this last year for these two causes.
Figure 2.9 gives more details about this situation. On the left side of the image, thevariation of registrations and portabilities that have been produced since January 2017 isrepresented. In this graph, it is clear that the company that has achieved the highest numberof registrations is MásMóvil, with numbers that are much higher than the rest.
As soon as Másmóvil appeared, Vodafone experienced an increase in portability. Andafter some months, Movistar and Orange have been affected as well. The main difference isthat both Movistar and Orange, have almost maintained their number of customers, thanksto the fact that they also had an increase in registrations, which offset their high number ofportabilities. But this is not the case with Vodafone, which, although also had high, thesehave not been enough to end the year in positive.
On the right side of the image, the total number of users who have won or lost these fourmobile telephony operators are represented. MásMóvil managed to end the year with 403,750
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more users than at the beginning of the year 2017. This amount is very high and shows thatthis company has earned a place in the Spanish market for mobile telephony. However,observing the other three companies, it is clear that all have lost users. So, it is possible toaffirm that these users made their portabilities to the operator of MásMóvil. Among thesethree companies, Vodafone has the worst results, with a loss of 243.900 users in one year.These results are the worst numbers they have ever had. Although Movistar also has losses of129,235 and Orange of 145,650, the user losses of Vodafone are still significantly bigger.
Figure 2.9: Registrations and portabilities of 2017 in Spain [4].
Although Vodafone finished in the third position in a number of lines in 2017, it has beenthe company with the best results in the tests carried out by companies specializes in wirelesscoverage mapping. This thesis will discuss the results in particular of one of these companies:P3 Connect Mobile Benchmark.
It measures network quality and identifies potential areas for improvement. The reasonwhy this company is commented here and not other it is because its results are highlyobjective and it is considered authoritative.
The tests were carried out in cars that travelled through 17 large cities of Spain (with morethan 100,000 inhabitants each), as well as in small towns. In total, P3 Connect Mobile Bench-mark ended up covering 11,520 kilometres in October 2017. The measurements were madeusing mobile phones that perform measurements of the voice and data services configuredwith 4G.
For voice tests, test calls were made between vehicles and the quality of the audio wasevaluated using broadband algorithms. And for the measurement of data tests, the maximumdata volume was evaluated in uplink and downlink. Measurements were also made in videostreaming, adapting the resolution of the video depending on the available bandwidth.
The results show that all Spanish mobile operators have improved their networks com-pared to the previous year. But only Vodafone has managed to stand out above its competitors,remaining in the first position for the third consecutive year. Figures 2.10 and 2.11 have theresults of these tests.
Vodafone has the highest scores, both in voice and data, although it was not in the firstposition in crowd score. Movistar has the second best results, followed closely by Orange.
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However, Yoigo was in the fourth position with the worst results, and very far from thethird [3], [2].
Figure 2.10: P3 Measurements Results [3].
Figure 2.11: P3 Overal Results [3].
Looking more closely at the results in Figure B.1, it is possible to see the most representa-tive values of voice measurements. They show the percentage of success in the calls, the timeof configuration of the call (in seconds), as well as the average quality of the voice call.
Vodafone continues to occupy the first place followed by Orange with regards the voicequality during calls. In addition, with respect to the success rate, Movistar ranks second,approaching Vodafone, which is again the first with an average success rate of 98.5% in all
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measured areas. However, in the time necessary to establish a call, Orange occupies the firstposition being the fastest operator with an average of 3.3 seconds per call. In the case ofYoigo, the results obtained place them in the fourth position in all fields.
Moreover, the results of the measurements made for evaluate the data transmissions,are in Figures B.2, B.3 and B.4. These images have the drive-tests in Cities Towns and road,respectively. The measures were carried out in the 4G networks of the operators (although itshould be noted that, in the case of Yoigo, they still do not have the full deployment of LTEnetwork). The results show that Vodafone is the clear winner over its competitors in all thecomparative analysis that were made. Movistar obtained the second position and Orangethe third. Yoigo, although it was in the last position, showed a remarkable improvement withrespect to the previous results of P3 connect Mobile Benchmark [2].
2.5.2 CUSTOMER SEGMENTATION
Vodafone is well diversified geographically. Actually, it has subsidiaries spread all over theworld: Albania, Australia, Czech Republic, Egypt, Faroe Islands, Germany, Ghana, Greece,Hungary, Iceland, India, Ireland, Italy, Malta, Netherlands, New Zealand, Portugal, Romania,Spain, Turkey, Qatar, UK, and Ukraine.
However, the highest amount of Earnings Before Interests, Taxes, Depreciations and Amor-tizations (EBITDA), was achieved in Europe. Figure 2.12 has represented this distribution.This is closely related to the number of mobile users in each country. That is because, inEurope, there are many more mobiles per person than in other continents as in Africa, Asiaor the Pacific. This is why the difference between continents is so big.
Vodafone’s customers consist of retail customers, third-party resellers and corporatecompanies. Actually, 92% of its customers are individuals and families while an 8% areenterprises.
Within the individual clients, their main target is people from 13 to 65 years old, and mostof them are located in urban, semi-urban and rural areas. Although more specifically, theVodafone’s target would be, youth and people located in urban and semi-urban areas, wherethere are more people who are willing to pay more for a premium service. Actually, the largestdata consumption is among people aged 18 to 30 located in urban areas, [33], [8].
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2.6 VALIDATION
Once the decision to virtualize the network was made, many studies and manuals were madein order to know the theory of how to implement this solution. However, it is not a good ideato start virtualizing the whole data core network based only on these manuals since manyfailures can occur during the implementation and many users may be affected.
For this reason, during the validation phase, a testbed line was created, which was smallercompared to the production lines, but large enough to validate the entire virtualizationprocess. All the testbed line was created by using Huawei HW.
First of all, the entire HW infrastructure was placed to form the testbed line, which wasformed by three clusters. Then, on this HW, the SW needed to implement all the NFVs, suchas vUSN, vUGW, DGW and CGW, was installed through virtualization tools. Subsequently,these NFVs were tested to validate its correct functioning. The tests that are used for SWvalidation, are listed in the Appendix C. To see more information about how the process ofimplementing this testbed line was, go to Chapter 5.
The next step after validating the SW is to migrate a small number of users to this testbedline to ensure that everything works well without incident. During this process, the testbedline is continuously monitored, and analyzes are taken to check its performance. Once thisvalidation has been carried out successfully. The rest of Vodafone’s production lines can bevirtualized following the same steps mentioned above.
Chapter 3 has more detailed information about how was the entire process of the virtual-ization project.
2.7 GO TO THE MARKET STRATEGY
Vodafone deals in vertical business called Mobile Telephony. One of main Vodafone’s objec-tives is to ensure the loyalty of its customers by providing high-quality services.
Vodafone will price its future products and services in a competitive way in order to beatits competitors. The main products and services are pre-paid, post-paid and Value-AddedService (VAS).
The pricing strategy will be done differently for each segment that Vodafone targets,depending on its necessities. Therefore, each customer segments will be charged dependingon the type of tariff that they have contracted. Besides, Vodafone will add products likemobile phones, to make the tariffs more attractive to the customer.
Base on the quality of service, such as high speed, bandwidth, type of data traffic, thetariff price will be one or another, where the higher the quality of the service, the higher thepricing. However, the price campaign will also be adjusted taking into account the prices ofthe products and services of its competitors.
Their services an products are sold through customer care centers, physical shops, onlineshop, and independent retailer shops. Furthermore, they have distributed across the countrythanks to its strong distribution network.
The way that Vodafone wants to sell these products and services are mainly based onadvertising it. The idea is to make an aggressive marketing campaign, promoting the brand
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CHAPTER 2. BUSINESSS PLAN
through TV, press, prints, online, radio (Vodafone Yu program), and social media advertise-ments, among other channels. Additionally, Vodafone will promote its services and productsthrough sports stars and celebrities in their advertisements to attract all kind of audiences. Infact, associate the brand with such stars, it is already demonstrated that increase the brandvalue.
Once launched this campaign, Vodafone will keep track of the development of the cam-paign and it will investigate to determine how the campaign is perceived by consumers. Aswell as to know how is the satisfaction of the users using their products and services.
For Vodafone, its highest priority is its customers, that is why it is very important for themto know how their customers’ satisfaction is. So, they can modify and improve their servicesas soon as possible, and thus always guarantee the best experience for their customers [19].
16
3
PROJECT PLANNING
In this section, all the project plan is explained. The purpose of this part of the thesis is toprovide the reader with an overview of which were the activities that were carried out duringthe project. For it, the activities and their schedules will be described below, using the methodProject Management Professional (PMP) of the Project Management Institute (PMI), whichuses different tools, such as: Precedence Diagram Method (PDM) and Gantt chart.
Moreover, the last part of the section will describe the budget scheme used, includingsome of the elements which are part of the CAPEX and OPEX of the project.
3.1 TIME PLAN
In this section, the time plan of the project will be shown by using a type of bar chart calledGantt. The Gantt chart is a graphical tool used in project management, which uses bars toillustrate the expected dedication in time of different tasks over a given total time.
First of all, the activities were listed in a generic way. That is not in indivisible activities, butin tasks that host other activities, see Figure 3.1. For example, let’s consider the duties involvedin this proyect, which are: Test bed preparation, 5Tth Gi Line Legacy, vUSN and vUGW testing,Virtual Mobile Subscriber Equipement (vMSE) testing, vUSN and vUGW deployment, vUGWtraffic migration, vMSE deployment, acvUSN and vUGW traffic migration, and vMSE trafficmigration.
Besides, to have more complete information, the most important milestones achievedduring the realization of the project have been also added to this chart. The milestones arerepresented by starts, as it is possible to see in the right corner of the Figure 3.1.
Although not all the activities mentioned above are going to be explained by this thesis, itis important to mention all of them. The idea is to provide the reader with an overview ofthe type of activities necessary to virtualize a core data network. For example, although thisthesis will mainly talk about the vUSN and vUGW, vMSE was also developed in parallel. Thisnode was not included in the thesis for lack of time, since, as it is possible to see in the timeplan, most of its activities were planned to take place between August and October 2018.
Below is a brief explanation of the most relevant activities of the project, indicating whythe duration of each of them:
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CHAPTER 3. PROJECT PLANNING
Test Bed Preparation: Before virtualizing the production lines of the Vodafone network,tests were first carried out on a test bed line. For that reason, this testbed line had to bebuilt, practically from the beginning. So, the number of activities that had to be doneduring this process were many: HW purchase, HW delivery, connectivity design, andHW installation and configuration. In addition, all the bureaucratic processes involvedin each of the mentioned sub-tasks took also time into account. Therefore, taking intoaccount all these reasons, the Test Bed Preparation was organized to finalize it into 16weeks. To know information about the technical development of this activity go toSection 5.1 and 5.3.
Testing vUSN & vUGW: During this duty, both nodes were tested in order to validateits software. The assigned time for this task was 9 weeks. To do all these tests it wouldbe enough in 6 weeks. Nevertheless, taking into account that it was the first time thenetwork was virtualized, it was decided to increase this number of weeks to 9. So, itwould be enough time any unexpected in the case of finding errors.
Deployment vUSN & vUGW: Once the correct functioning of the software has beenverified, it is time to deploy these NEs in other locations in Spain to cover the en-tire Vodafone production network. This activity took one month. Two weeks for thedeployment, and two weeks to check that everything worked well.
Traffic migration: This last activity consisted of migrating all the users of the Vodafonelegacy lines, to the new virtualized lines. This step is one of the most critical since anyfailure in the system is noticed by the users.
All these activities mentioned above will have an explanation in greater detail, in Section 3.2.
18
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APT
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3.PR
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Figure 3.1: Gantt Chart: Main Milestone.
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CHAPTER 3. PROJECT PLANNING
3.2 PRECEDENCE DIAGRAM METHOD (PDM)
In order to develop a schedule network diagram, which tracks all the activities involved in theproject, it was carried out the table 3.2. This table was built using the PDM method based onthe PMP certification. Each task or activity has their own duration and dates with their EarlyStart (ES), Late Start (LS), Early Finish (EF) and Late Finish (LF). All these dates are in weeks,taking as week 0 the first week of the project, right after the kickoff ended.
Once the dates were determined, it was taking into account the delays that each task ofthe project can tolerate before the project comes in late. These delays are called Float, and itis calculated by subtracting the value from the LF with the value of the EF or by subtractingthe value from the LS with the value of the ES. In both cases, the result should be the samevalue.
Once the table was finished, it was constructed the diagram which was made usingboxes/nodes and arrows. Here, each task was represented by boxes. In addition, each arrowshowed the dependencies among these activities.
Furthermore, the Duration and the Float of each task, are also represented. Thanks to this,after doing the representation, it is easy to realize which is the critical path of the project (inred), as well as the nearest path to the critical one (in grey). The resulting schedule networkdiagram is shown in Figure 3.3.
Next, there are listed all the activities involved in the project, with a brief explanation oftheir aims:
Task 1: Service Investigation. During this task, a broad investigation was carried outinternally, as well as with the vendor. In it, some of the main topics where discussed:Design, elements, functionalities, Internet Protocol (IP)/Virtual Local Area Network(VLAN)s configurations, connectivity. Moreover, in order to introduce and share thesolutions agreed upon at this stage, a kickoff was carried out, where both the vendorand the operator were part of this event. However, all this information was gathered indifferent manuals, so people could consult them at any time (it should be noted that noteverything that was agreed at this stage was completed later. This was because duringthe project different decisions were made that caused changes in these previouslyagreed solutions).
Task 2: High Level Design (HLD). In this step, a manual called HLD was createdby Vodafone’s members. It explains the preliminary stages of the End-to-End (E2E)architecture that should be followed in order to develop the software products. Insidethis manual, there is a NFV Overview, connectivity solutions, Virtual Evolved PacketCore (vEPS) details, and explanations of the different functionalities of the nodesinvolved in the project.
Task 3: Connectivity Design. During this stage, several meetings were held in orderto find out which connectivity option was the most suitable for the data core networkof Vodafone Spain. The decisions were made mainly keeping into account the HLDpreviously developed, as well as features of the data core network.
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CHAPTER 3. PROJECT PLANNING
Task 4: Connectivity Demand. Once the connectivity design was done, the followingstep was to make the demand for the different IPs and VLANs necessary to carry outthis design.
Task 5: IP Configuration. After having the IPs and VLANs required, they were config-ured in each of the blades on its location. This configuration was carried out followingthe implementation manuals provided by Huawei.
Task 6: LLD. Here, it was written the LLD, which describes the process step-by-steprequired by the software architecture of each of the nodes. It is based on the previousHLD design. This particular step was made by the Huawei, the vendor in charge of thevirtualized elements.
Task 7: Integration&Comissioning CSM (TR5). During this phase, the CSM was inte-grated and commissioned. This step is a critical task since the CSM is in charge of themanagement system for Huawei virtualization devices. It is important because, it isused to create, configure, activate and hang up the Virtual Machine (VM)s. Therefore, ifthis step fails, there is no way to continue with the project.
Task 9: Integration&Comissioning VNF: vUGW & vUSN (TR5). Once the CSM wasready, the infrastructure was ready to do the integration and commissioning of thevUGW and vUSN. This task was carried out, following step by step the Huawei manualsfor integration of the different elements of the network. In addition, it was taking intoaccount the middleware to succeed between communications among applications.
Task 10: TR5 Testing. This step is the first stage of tests that are performed on thenodes for their approval. In TR5, the performance of each node is tested, and with theresults, the necessary changes are made to the software to improve it.
Task 10.1: vUSN with release 18.1 TR5 Testing
Task 10.2: vUGW with release 18.1 TR5 Testing
Task 10.3: vMSE with release 18.1 TR5 Testing
Task 11: TR6 Upgrade & Test. Once the nodes have passed the TR5 phase, several testsare carried out again to guarantee the correct functioning of each element. Some of theTR5 tests are repeated at this stage of TR6, with the purpose of placing the last patcheson the nodes before launching them into production.
Task 11.1: vUSN with release 18.1 TR6 Upgrade & Test
Task 11.2: vUGW with release 18.1 TR6 Upgrade & Test
Task 11.3: vMSE with release 18.1 TR6 Upgrade & Test
Task 12: General Available (GA) Upgrade & Test. This is the GA phase where it isdecided if the release of the nodes is ready to go into production or not. In the case ofdeciding that it is not ready, the last patches are made.
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CHAPTER 3. PROJECT PLANNING
Task 12.1: vUSN 18.1 GA Upgrade & Test.
Task 12.2: vUGW 18.1 GA Upgrade & Test
In order to understand better the different phases of testing, the following Figure 3.2 hasrepresented in a visual way the different phases of the test, as well as certain activities thatform them (notice that the VM1/Charter is the kickoff’s releases). In addition, Table 3.1 showswhich kind of features and functions are available for test in the consolidated vUGW-TrafficManagement Function (TMF) [13]:
Figure 3.2: Test availability CE18.1 TR5 vs.TR6 vs. GA [13].
Task 13: vBOM & pBOM. These two activities consist of elaborating documents whereall the technical features of the elements that will be necessary for the implementationof the nodes will be detailed. The Virtual Bill of Materials (vBOM) is the first to bemade. It contains the specifications of the virtual elements, such as the VM types, thenumber of VMs required, the number of interfaces for each VM, vCPU, RAM, affinityrules, among others. Once this document is done, the Physical Bill of Materials (pBOM)is implemented, where the physical elements necessary to contain all the parametersindicated in the vBOM are found. For example, the number of blades per node.
Task 14: Hardware Purchase. To carry out this duty, a document with detailed infor-mation about the purchase has to be prepared. In it, the prices of each HW elementthat is going to be purchased are broken down, as well as the total price of the purchase.This document is sent to Vodafone members in charge of evaluating the budget, and
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CHAPTER 3. PROJECT PLANNING
therefore accepting or rejecting it. In the case of being accepted, the purchase of theHW can begin, directly by contacting the suppliers.
Task 15: Hardware Delivery. This phase consists of the time necessary to receive thepreviously purchased HW.
Task 16: Hardware Integration. Once the HW has been received, it can be installed.This procedure is done by integrating the new HW to the old infrastructure alreadyinstalled.
Task 17: TR6 First of All First Offial Application (FOA). Once the HW was integrated, itis initiated the FOA of each of the NEs. This phase consists in migrating a small numberof users to the line, from a small area of Spain. The performance of the network will bemonitored for two weeks. If all goes well, the rest of the users will be migrated after thistrial period.
Task 17.1: vUSN 18.1 TR6 FOA
Task 17.2: vUGW 18.1 TR6 FOA
Task 18: vUGW Traffic Migration. This is the last activity before considering the nodeis completely integrated with the core. This step consists in migrating all the users whowere using the legacy data core network, to the new virtualized data core network. Thisis a critical process since any failure could be noticed by users. That is why, it is donestep by step in two weeks, to avoid errors in the network and control their behaviour.Once all the migration of the users has been completed, it just left maintaining andmonitoring the node to avoid anomalous behaviour or solve possible incidents.
This section will expose the most important economic factors that were taken into accountto make the decision to virtualize the Vodafone’s data core network. The data shown belowcomes from the budget proposal offered by Huawei to Vodafone. Since the data core networkwas virtualized with products of this company.
In order to keep confidentiality, note that all the data that is going to be exposed below isnot the real one but approximations.
First, the budget of a hypothetical project scenario will be presented. In this scenario,the data core network is not virtualized. Secondly, a scenario with the data core networkvirtualized will be shown. So, knowing both scenarios, it will be very easy to compare them tosee which is better.
Figure 3.4 shows the cumulative values for the next five years of the two scenarios men-tioned above. In this graph, it is possible to see that as the years go by, the difference between"Doing nothing" and virtualizing, is increasingly noticeable. In fact, this difference reaches10 million euros in the fifth year.
Furthermore, after these first five years, the forecast is that this budget difference willcontinue to increase, saves a lot of money in Vodafone.
This big difference is mainly due to the fact that the initial investment that has to bemade in HW and SW for virtualization, is much less than what should be done in HW in the"Do nothing" scenario. Besides, the maintenance required by this HW equipment is veryexpensive, so that having less amount of HW in the virtualization scenario, these OPEX costsare very low.
Figure 3.4: Comparison between “Do nothing” scenario vs. Virtualization.
All the data shown in the previous graph, are taking into account all the elements of thedata core network necessary to implement all its functionalities. However, the following datawill show only those values that are related to this master thesis, ignoring the rest. Therefore,the total costs will be lower.
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CHAPTER 3. PROJECT PLANNING
In order to have more details of how the budgets of the previous scenarios are composed,Figure 3.6 and Figure 3.5 show the CAPEX of "Do nothing" scenario and Virtualized scenario,respectively.
The first detail that can be highlighted is that for the "Do nothing" scenario, more elementshave to be contemplated than for the virtualized one. This is mainly due to the HW that isused, as well as the complementary elements that this HW needs.
Another fact to take into account, is that in the virtualized scenario, although the costs ofprofessional services are more expensive at the beginning, with the years are cheaper, being avalue well below than the other scenario.
In addition, in virtualized environments, there are no added costs for Operation SupportSystem (OSS) licenses, when in the other scenario there are.
With all this, the costs generated by a non-virtualized scenario would amount to 21.474k". Nevertheless, virtualizing the network would be 16.492 k".
The difference that exists between the two cases, as it was shown previously, will beincreasing. So it is clear that use a virtualized environment is much more economical.
Vodafone’s legacy network is a non-centralized network, where each of its NEs are built indifferent HW, see Figure 4.1. Although this HW is very sophisticated, every time it is neededto add a new functionality to the network, a big investment in HW has to be made. As aresult, this kind of networks have a high cost and in the long term, they are not profitable.Besides, the nodes do just one function per entity, which makes the network less flexible andinefficient.
As it was shown in previous chapters, the world of telecommunications is constantlyevolving and customers expectations are constantly growing. Therefore, it is necessary toadapt the network to these new needs.
This chapter will give an overview of some key concepts to understand how important isto use virtualization for future 5G networks.
The chapter is divided into three parts. First, The techniques needed for virtualizationwill be explained in detail (e.g. NFV and SDN).
Secondly, the new virtual network architecture in Vodafone will be introduced by explain-ing the most important elements and services.
And finally, an introduction to the 5G networks will be made, where the most significanttechnologies will be explained (e.g. MEC, CUPS, NSA and SA networks, and network slicing).
Figure 4.1: Old Vodafone’s Topology
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CHAPTER 4. TECHNICAL BACKGROUND
4.1 TECHNIQUES FOR VIRTUALIZATION
Virtualization is the technology that allows sharing capabilities of physical storage, comput-ing and network by dividing these resources among different VMs. The first time that theconcept of VM appeared was in 1964 [24] with IBM. Nowadays, there are many virtualizationtechniques that all to support the execution of operating systems in VMs (e.g. NFV andSDN), [24].
Following, two techniques used for virtualization will be presented in this chapter.
4.1.1 NFV
Figure 4.2: NFV Basic Architecture [7].
In general terms, NFV is a new network architecture concept which uses technologiesto virtualize NEs and connect them in order to create network services an applications.Therefore, thanks to NFV it is possible to redefine the way of delivering and operating thenetwork functions.
Some of the technologies used by NFV are standards IT and cloud technologies. Withthem, NFV can create a new architecture, where network functions, as well as the applications,are entities create by only using SW. In addition, these SW entities are independent of theHW and use resources like, network, compute and storage elements as the HW platform.
Moreover, with this new architecture, it is possible to develop new SW functions andapplications in an easy way. Hence, there are more vendors which can implement newfunctions and application. This translates into a more diverse ecosystem of vendors in
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CHAPTER 4. TECHNICAL BACKGROUND
comparison with the legacy architecture. Besides, NFV brings innovation and with this, newbusiness opportunities through the new services that can be provided to the customers.Furthermore, NFV is able to optimize the resources of the network, so there is a reduction ofthe CAPEX and OPEX needed.
All the advantages that NFV provides, made Vodafone decide to use this new technologyand modernize its data core network. Therefore, Vodafone is consolidating functions ofits NEs, reducing the number of HW platforms. For instance, if it is compared to the oldVodafone’s architecture (Figure 4.1) and the new one (Figure 4.4), the number of nodes hasdecreased. This is because the new vUGW has integrated more functions as the old UnifiedPacket Gateway (UGW) had (see more information regarding this topic by going to the fol-lowing Subsection 4.2.1). With this, Vodafone is improving its cash flow and providing betterservices to their customers, [12], [7].
Figure 4.2 has the NFV architectural framework, with its four main areas, [32]:
• OSS and Business Support System (BSS)
These two systems work together in order to support network services. In previousversions, OSS and BSS were entities more separates. However, since the services aremore and more complex, these two entities have needed a closer liaison between them.
OSS and BSS are structures with technology-oriented to include new services intothe network. These services are built using Service Fulfillment Functions (SFF) thatis in charge of the service design and resources provisioning, and Service AssuranceFunctions (SAF) that handle the assurance processes (e.g troubleshooting).
Nowadays, these new processes carried out in the OSS, are compatible with the newNFV and SDN technologies.
• VNFs
A VNF is a virtualized version of a traditional network function which is implementedby SW simulating functions built in HW. Some examples of VNF are the vEPC and thecomponents that form it: Mobility Management Entity (MME), vUSN, vUGW (formedby Packet Data Network Gateway (P-GW) and Serving Gateway (S-GW) platforms), andfirewalls, among other elements.
The main idea is to implement this virtual platforms in the core by using the lowestpossible number of HW and running it over the NFVI. This is possible since VNF canbe implemented as a VM or multiple VMs, or even as a function implemented within ashared VM.
• Virtual Network Functions Infrastructure (VNFI)
This subsystem consists of all the HW (e.g. physical servers, storage, and networking)and also SW (e.g. virtual servers, storage, and networking) components on which VNFsare deployed. In addition, it includes the compute, storage, and networking resources,as well as the associated virtualization layer called hypervisor and the container whichholds the VMs.
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CHAPTER 4. TECHNICAL BACKGROUND
The hypervisor is an operating system, which provides a level of abstraction. It abstractsthe host infrastructure and allows to use it as a pool of virtual resources. Therefore, allthe virtual resources can be consumed by VMs. Therefore, the hypervisor is one of themost important components in virtualization.
• Management and Orchestration (MANO)
It provides orchestration and lifecycle management for the virtualized resources of theNFVI and the VNFs. Inside this subsystem, there are three functional blocks together,which are: Virtualized Infrastructure Manager (VIM), NFV Orchestrator (NFVO), andVNF Manager (VNFM). All these blocks allow communication between NFV andMANO.
– VIM is a management system which controls and manages the compute, storage,and network resources of the NFVI. The following description gathers some of themain VIM activities:
Resource management, where it is included in the management of the SW inven-tory, hypervisors, and the virtual compute, storage and network resources. Inaddition, it allocates resources, as well as assigns dynamic resources and power.
Another key activity is the operations management to visualize and manage theNFVI, and data collection.
– NFVO manages networks services that include multiple VNFs. It is able to createend-to-end services using several VNFs. In addition, it also manages the lifecycleof Network Services. During this VNFs lifecycle, there are some key activities like:Onboarding a network service, instantiating a network service, scaling up or downa network service, and updating a network service.
– The VNFM is an entity which is in charge of the management and operation of theindividual VNFs. Normally, this management is focused on Fault, Configuration,Accounting, Performance, and Security (FCAPS). However, currently with thenetwork virtualization, there are more features of managing the lifecycle of theVNFs. Some of its tasks are the following:
* Creation of VNFs by the use of templates and parameters.
* Increase or decrease the capacity of these VNFs by scaling up or scaling down.
* Update and upgrade VNFs.
* Finalize the VNFs and returning them to the NFVI resoruces pool.
4.1.2 SDN
SDN is a set of techniques used for network transformation since it can face the new chal-lenges and changes that are appearing in the network area. Thanks to SDN, it is possible tomanage, control, optimize, arrange and distribute the network resources. In addition, oneof the basic ideas of SDN is the separation of the architecture in two traffic planes: One forsignalling and another for data. This makes SDN a centralised network architecture.
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CHAPTER 4. TECHNICAL BACKGROUND
Another basic idea with regard SDN, is the capacity it has of abstract the network infras-tructure from the applications. Thanks to this, SDN allows having a new logical-centralisedcontrol system which is programmable and makes the network architecture more dynamicand scalable.
Besides, it is not necessary to buy new HW, since the existing one can be configured andprogrammed. Hence, SDN is also cost-effective, reducing the overall costs.
In general terms, the principles of SDN are:
• Separate user plane from control plane.
• Standard protocols for interoperability.
• Create an open platform.
• Apply network wide.
SDN can be divided in two main areas, as it is shown on Figure 4.3: SDN Application layer,SDN Controller.
The most important part of those mentioned above is the Software Defined NetworkController (SDNC) cluster, which is the controller in charge of deciding where and whensending the control flow and data flow. These flows which go through the SDNC, can bedivided into three sections:
1. Real-time network status.
2. Service demand.
3. Automated provisioning of physical network nodes.
SDN provides a visibility of the real-time status of the traffic-flows as well as the networkresources. When the SDN controller notices there is a new service demand, it can automati-cally provision the whole network resources E2E. Furthermore, the centralised controller isable to optimise the paths for all the services and compute the network taking account theoptimal view that it as calculated, [22].
Vodafone has introduced SDN in theIP/Multiprotocol Label Switching (MPLS), Opticaland Microwave transport domain. For it, Vodafone had to define the SDN for single TransportNetwork architecture. In addition, Vodafone is currently introducing SDN over the NFVnetwork. As a result, it was obtained an improvement in the current network assets thanks toautomation and resource optimization. In addition, it has also facilitated the design, deliveryand operation being dynamic and scalable.
To summarize, the following list has an overview of the main reasons why Vodafone is usingthis SDN technique, [7]:
• Introduce programmability and maximise automation.
• Optimise transport resources usage.
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CHAPTER 4. TECHNICAL BACKGROUND
Figure 4.3: SDN general structure [7].
• Dynamic centralized decisions based on the E2E network view.
• Full coordination among the inter-layers.
• Dynamic establishment of various services according to demand.
• Better performances and resiliency.
• Real-Time view and decision making (monitoring, analytics, and optimisation, amongothers).
• Easy and fast way to add new features and capabilities.
4.2 VIRTUALIZED NETWORK ARCHITECTURE AND SERVICES
This section is aimed at describing the new Vodafone virtualized network elements, as well asits functionalities. Besides, there will also be a brief introduction to the services that Vodafoneoffers to its users, to better understand how the Vodafone network works.
4.2.1 VEPC ELEMENTS
The new vEPC brings the possibility of consolidating functions in the same NE. Therefore,the final network architecture has less number of NEs than the old Evolved Packet Core (EPC),Figure 4.4 has represented the new vEPC. Specifically the vEPC is composed by two newnodes, vUSN and vUGW, which will be presented later.
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CHAPTER 4. TECHNICAL BACKGROUND
Figure 4.4: New Vodafone’s Topology
Although vUGW and vUSN are new virtual platforms with new functionalities, no inter-face changes with respect to the legacy architecture. Furthermore, they are based on thesame 3GPP standard in which was based on the old network.
Figures 4.5 and 4.6 have the structure of how is the vUSN and vUGW integration with therest of the network, as well as their interfaces.
Moreover, the Table 4.1 gather not only the NEs which are integrated with the vUSN andvUGW, but also the application layer protocol and the transport layer protocol, that eachinterface uses.
• vUSN:
In the current virtual network architecture, the vUSN is a triple access node, and itcarries out the functionalities of the old Serving GPRS Support Node (SGSN) and theMME. The following VMs are needed to implement this NFV:
– Operating and Management Unit (OMU)s: which are in charge of operations andmanagement of the NFV. (Scheme 1+1).
– Session Data Unit (SDU)s: which implements session context storage functions.(Redundancy scheme N-way).
– Service Processing Unit (SPU)s: which carries out processing and GPRS Tunnel-ing Protocol (GTP)-U transfer functions. (Redundancy scheme N-way).
– I/O Processing Unit (IPU), which deploys IP routing and session dispatchingfunctions. (Redundancy scheme N-way).
– Gb Interface Processing Unit (GBU): which deploys protocol functions in 2G.(Redundancy scheme N-way).
– Signal Interface Process Unit (SIU): which implements processing and GTP-Cfunctions. (Redundancy scheme N-way).
Table 4.1: vEPS Network Element Interconnect Relationship [35].
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CHAPTER 4. TECHNICAL BACKGROUND
• vUGW:
This NE is a consolidation of the old nodes Gateway GPRS Support Node (GGSN), S-GW,and P-GW, now called Virtual Multi-Services Platform (vMSP) and vMSE. In the newarchitecture, the functionalities that have to be implemented by the vUGW are thefollowing:
– Deep Packet Inspection (DPI).
– vMSE:
* Header enrichment.
* TMF steering, redirection to Vodafone Start and Secure Net.
* Transmission Control Protocol (TCP) optimization.
– vMSP:
* Web optimization.
* Video optimization.
In order to implement all these functionalities, were used the following VM [12]:
– OMU: which provides the daily maintenance and lifecycle management. (Redun-dancy scheme 1+1).
– IPUs: which are dedicated to managing signalling interfaces, such as: Gx, Gy, andRadius, among others (Redundancy scheme N-way).
– Assambly-Service Process Unit (APU)s. (Redundancy scheme N-way).
* This VM contains interfaces and service units.
* It is dedicated to managing just data plane IP traffic as received in the Gi-LAN.
* If it is required, this service unit can be able to manage all data plane traf-fic. In particular GTP encapsulation and decapsulation, and steering trafficenforcement.
– Service Function Management Unit (SFMU): This VM is responsible to controlthe service chain and provide to steering capability. (Redundancy scheme N-way).
– SDU: This VM provides the Cloud Session Database to support resilient andscalable service. (Redundancy scheme N-way).
– Video Optimizatin (VO)/Web Optimization (WO)-Front end: These VMs are pro-vided by the company OpenWave. They support both interface and service logicfor VO and WO. (Redundancy scheme N+1).
– VO/WO OWM Operation And Maintainance (OAM). This VM is also from Open-Wave. It supports Huawei functionalities to provide the daily maintenance andVNF Lifecycle Management. (Redundancy scheme 1+1).
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CHAPTER 4. TECHNICAL BACKGROUND
4.2.2 VEPC SERVICES
Below, some services that Vodafone provides to its users will be explained. Note that theservices that have been chosen are the ones which offer the greatest challenge with regardsthe network virtualization. Therefore, they have been taken into account in the networkimplementation:
• Vodafone Pass is the name of a new Vodafone’s monthly service, which brings newfunctionalities into the network. Vodafone Pass is divided in four different areas: VideoPass, Social Pass, Music Pass, Maps Pass (or Super Pass, in the case of having the fourcontracted).
In order to implement Vodafone Pass, it is necessary to know the type of traffic that eachuser consumes at any time (traffic based on application). Knowing this, it is possible tocharge consumers depending on the type of subscription they have. For example, ifa user has only a Video Pass subscription, all the video content that he consumes willgo at maximum speed, and it will not be discounted from the data allowance (i.e. 3GBmonthly), so the customer is able to consume this traffic without limit. However, therest of the traffic generated will be charged and will go at lower speeds.
So, once the traffic is identified, it is processed and goes through a data traffic settingrules, in combination with Policy and Charging Control (PCC) rules. The service chainis selected based on the user profile information received by the Policy and ChargingResource Function (PCRF). The decisions normally are taken in the Mobile SubscriberEquipement (MSE) and after, the traffic proceeds to its optimization.
In order to implement this promotion, the technical functions that were needed toinclude in the network were:
– DPI: Data processing that identifies the type of data that is inside the traffic flow.
– TCP Optimization: Since TCP was not created keeping in mind mobile networks,sometimes it causes congestion and slows down the performance in data transfers.This is why it was created processes through which TCP can be optimized andavoid these congestions.
– VO: It is a process which improves the video performance by reducing re-bufferingevents, enhancing customer viewing experience.
– WO: Set of technologies used to improve the performance of web pages, enhanc-ing the user experience.
Figure 4.4 has represented all the components involved in this process [12], [28].
• Vodafone Start is an intelligent redirection for subscribers with new smartphones. Theaim is to improve subscriber engagement with Vodafone and its products and services.
Once a subscriber tries to browse the internet with his new smartphone for the firsttime, the TMF redirects the traffic to a Vodafone Welcome website. This page offers theuser different services and products tailored to the customer and its device.
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CHAPTER 4. TECHNICAL BACKGROUND
After the user has been redirected to Vodafone Start, the page is displayed and TMFsends a notification to the PCRF to confirm that the user has been redirecting cor-rectly [12].
• Secure Net is another service offered by Vodafone. It provides safe browsing, antimal-ware and antivirus protection to the users.
All the users that are subscribed to this service, every time they surf the Internet, theirdata will pass through the Secure Net platform. This platform will identify the trafficand select which content is allowed to pass and which does not.
Therefore, for this process, TMF is requested to steer traffic to the Secure Net platform,keeping into account the PCRF rules [12], [26].
4.3 5G NETWORKS
5G is the fifth generation of mobile phone technology. This new technology brings greatadvances with respect to its predecessor 4G. However, 5G is more than an evolution ofLTE. This technology has new radio and core, as well as, a wider available bandwidth andlower latency. Furthermore, 5G brings new perspectives which are capable of changing thedemands of consumers and business markets. These new demands and business marketswill bring new applications based on 5G, which are going to change the digital. For instance,Remote control for robots or machines, Augmented reality, Gaming, Education and Training,Tele-operated driving and Autonomous driving-self-guided vehicles, among others.
The key technical characteristics which 5G needs in order to carry out all the changesmentioned above are listed below:
• Radio upgraded to reduce latency by 1 to 10ms. This will be very important for lowlatency services. For instance, Gaming, Augmented Reality, and Self-guided vehicles,among others.
• 5G spectrum deployed (700 and 35000MHz) and massive Multiple Input MultipleOutput (MIMO) antennas added to increase speed and capacity.
• A Peak data rare of 1 to 20 Gbps, bringing a better user experienced data rate of 10 to100 Mbps.
• Applications moved into the network to further reduce latency by many 10’s of ms
• Network slices to enable new services (e.g. s slice for "advanced gaming" or "con-nected cars"). Network slicing separates the user plane and the control plane providinghigher flexibility in configuration and reconfiguration of networks based on SDN.
• New devices supporting 4G Evo and 5G which can have a battery life of 10 years.
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CHAPTER 4. TECHNICAL BACKGROUND
In order to implement all these new features, it is necessary to create 5G Radio and PacketCore. For this goal, SDN and NFV are used, being the main enablers for 5G. They are the onesin charge of decoupling SW form HW and HW virtualization.
As it was explained before, 5G network will be able to support new technologies, use cases,business solutions and delivery models. For it, 3GPP is developing interworking scenariosbetween vEPC and 5G.
The planning of 3GPP is represented in Figure 4.7, where there is an overview of thepresent status and future plans of 3GPP. The first part of this diagram shows that the firstrelease (Rel-14) has been finished by the end of 2007. These advances have allowed the first5G tests to be carried out. In fact, Vodafone Spain with Huawei made the first 5G call in theworld by February 2018. And now, they are continuing with the first NSA tests (low latency,slicing, MEC). Although the last releases will not be ready earlier than 2019.
Figure 4.8 has the steps and enablers needed to reach the deployment of a 5G Packet Core.As it is shown in the image, the first step is to implement NFV (this mechanism was alreadyexplained in Section 4.1). With this network architecture, it was possible to virtualize the EPCand have a network ready to use CUPS, which is in charge of speed up the user plane services.
After implementing CUPS in the vEPC, it is time to use the 3GPP standard called NSA.With it is not necessary to have a 5G core since the radio goes through 5G, but the datathrough the virtualized 4G core.
Once the scenario is ready, is the time to introduce the concepts of MEC and slicing. Bothconcepts enable the network to have lower latency and create slices per service to use thenetwork in a more efficient way.
Although it is getting closer to use 5G cores with the SA standard, it will not be until 2020when we can make real use of it, as it is shown in Figure 4.7.
In the next subsections, it will be made a more detailed explanation of all the elementspreviously mentioned, for a better understanding of them.
4.3.1 MEC
MEC is a network architecture concept that brings cloud computing capabilities and ITservices environment closer to the Radio Acces Network (RAN). Therefore, with MEC, ispossible to host services at the edge of the network placing them closer to the end-user, andtherefore decreasing the latency significantly.
Thanks to this concept, it is possible to do specific tasks that before not possible to bedone using traditional mobile networks. Actually, the main idea with regard MEC, is that isable to run applications and performs tasks closer to the User Equipment (UE). Thanks tothis, network congestion is reduced significantly, getting better the application performance.Moreover, MEC allows deploying new applications and services in a more flexible and fasterway.
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CHAPTER 4. TECHNICAL BACKGROUND
Figure 4.7: 3GPP Standard Progress [9].
Figure 4.8: 5G in Packet Core - Steps and Enablers [9].
MEC is able to create new environments with the following features:
• Higer proximity to the user, which allows gathering information for analytics and bigdata.
• Ultra-low latency allows creating services that need to react fast improving the userexperience.
• Higher bandwidth permit to deploy application and services which can not be appliedto legacy networks.
• The Location awareness lets to locate devices with a high degree of precision. Besides,this feature allows devices to have a large set of applications only dedicated to specificgeographic areas.
• The Real time access offers context-related services which are able to differentiate thebroadband experience.
Combining all these elements, mobile operators are able to create networks which canprovide: Low latency, better flexibility, agility and faster delivery. This gives the opportunityof increasing the quality of the services and make the user having a better experience, seeFigure 4.11. Furthermore, it makes network operation more cost-efficient and competitive.In addition, thanks to this service environment, the access to new content and application itis faster and more interactive [9], [31], [36].
Figure 4.11: MEC network architecture [31].
4.3.2 CUPS
CUPS is one of the most important pillars of 5G core network architecture. Although theseparation of the control and user plane has already been implemented in the EPC, in 5Garchitecture has a completely new definition.
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CHAPTER 4. TECHNICAL BACKGROUND
CUPS was created with the purpose of handle scenarios which have several traffic flowsthat involve remote and geographically distributed systems. In order to control these trafficsflows, a large number of small gateways were needed. These gateways are in charge offorwarding the IP packest and placed it near the radio access.
The control plane and user plane are separated, where it is processed signalling andservice data respectively. On one hand, the control plane provides unified signalling interfacesthat make it simplify the network deployment. On the other hand, the user plane is deployedat the regional network, so it shortens the service access path.
Furthermore, the planes can be established in different sites. For instance, the controlplane can be placed in a central location. This central placement allows to manage and con-trol traffic flows with less complexity. User plane can be distributed over different locations,closer to the user and the RAN.
Thanks to this new organization of the network, latency is reduced and the paths of theuser traffic are optimized.
Besides, with CUPS, it is possible to manage all the functions needed to forwards thesepackets by using a limited number of centralized control nodes.
To sum up below is shown some of the most important CUPS architecture features:
• The separation between the control plane and user plane that CUPS provides makesthe resources to be scaled independently.
• Path optimization and reduction of latency since the user plane is deployed at theregional network or even lower to shorten these paths. This feature makes better theservice experience.
• Large number of small gateways, which forwards IP packets and placed it near theaccess.
• Limited number of centralized control nodes.
• CUPS is able to handle traffic-flows in remote and geographically distributed systems.
Currently, Vodafone is using Huawei NEs to renew its networks, and Huawei has bet verystrongly for the use of CUPS in its products. Actually, the Huawei solution for 5G core networkis completely based on this concept. Figure 4.12 has represented the before and after of anvUGW node.
On the left side of the image is the vUGW with control and user planes together. So, allthe traffic goes through the same centralized node. However, on the right side of the image,there are two nodes instead of one: CGW which is in charge of the control planes, and DGWwhich manages the user plane.
This new architecture is the one that was used for the testing in 5G of this master thesis,see more information going to Section 5.5.3.
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CHAPTER 4. TECHNICAL BACKGROUND
Figure 4.12: Huawei Separation Solution [18].
4.3.3 NON STAND-ALONE AND STAND-ALONE NETWORKS
NSA and SA are two types of 5G networks defined on the standard 3GPP Release 15. As it wasshown in Figure 4.7, the first class of network to be implemented is NSA and after SA.
NSA allows the use of 5G in the Radio Access without the need of having great upgradesin the vEPC. This means that it is possible to use the virtualized 4G network infrastructurewithout the need of having the complete 5G core.
With NSA, smartphones can connect to 5G frequencies and transmit and receive datausing the user plane. However, the control plane and some parts of the user plane, still goingthrough the 4G radio access and core [20]. Figure 4.9 has represented this scenario.
SA network it has not been implemented yet, and the 3GPP standard does not have eitherinformation with regard to it. However, the general idea is well known, see Figure 4.10. In thiscase, both control plane and user plane, use the 5G radio access and core, without the needof 4G infrastructure.
This type of network is expected to arrive by the end of 2019 or by 2020 when there aresmartphones that support this type of 5G technology.
SA will bring mainly simplification and improved efficiency. As a result, it is expectedto have, lower latency communications, lower costs, and a performance improvement inthroughput [20].
During this thesis, a NSA 5G tests have been carried out. In order to see the results, goto Subsection 5.5.3.
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4.3.4 NETWORK SLICING
Network slicing is one of the most important drivers of 5G. It is a powerful virtualization toolwhich is fundamentally a partition of the network resources and network functions. This newvirtual network architecture is based on the same principles used in fixed networks: SDNand NFV. These technologies allow to divide the NEs into new customizable elements, whereputting together some of them, can be used to provide specific services to the customer.All this, by using just the necessary resources of the network for this specific application orservice. Figure 4.13 has represented how is the slicing network structure.
Therefore, with network slicing it is possible to run multiple logical networks, using it asindependent business operations, and all this in the same physical infrastructure. Hence,slicing introduces flexibility into the network, and makes easier to manage it [9], [17].
The following list has some of the benefits that network slicing brings to the network:
• Eliminates complexity in the interaction between services and applications.
• Allows selecting specific applications and services by tuning of the network, makingbetter the user experience.
• Facilitates fault controls without affecting other slices.
• Allows independent upgrades and downgrades for each service and application.
Slicing is one of the main technical and business challenges that mobile operators andservice providers will face soon. Some of the principal technical parameters to keep in mindare the following: data rate, latency, Quality of Service (QoS), availability, and security amongothers elements. Moreover, in the business area, the parameters to keep into account are thenext: revenues per service, flexibility, cost-optimization and performance-optimization [11].
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Figure 4.13: Slices for different applications and environments [9].
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5
DEPLOYMENT
This technical chapter is divided into four parts. First of all, the physical and virtual elementsthat have been used to improve Vodafone’s network infrastructure are explained. Secondly,the design of the connectivity is shown, as well as all the options that were discussed beforeselecting the final design. Thirdly, the steps required to instal and configure the NEs aredescribed. And finally, the tests carried out for the SW validation of the platforms and theirresults, are explained.
Every decision that has been made in this chapter, has been based on the forecast for theupcoming months. As it was shown in Section 2.3, data traffic is constantly increasing, andtherefore the network has to adapt to these forecasts.
In order to cover this needs, the first step is to create the vBOM that contains all theparameters necessary to model and dimension virtual hardware needs. In it, the number ofVMs, Virtual Central Processing Unit (vCPU) per VM, RAM in GB per VM and the storage perVM are defined. Figures 5.1 and 5.2 have the details of these vBOMs for the vUSN and vUGWrespectively.
Figure 5.1: vUSN vBOM. Figure 5.2: vUGW vBOM.
5.1 NETWORK FUNTION VIRTUALIZATION INFRASTRUCTURE
During this section, an overview of the NFV architecture will be exposed. With this purpose, itwill be presented the NFV infrastructure components that were used to virtualize the network.
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The section is divided into three parts: physical elements, virtual elements, and the NFVImanagement necessary to handle the whole virtual infrastructure.
As it was shown in Section 4.1, the network architecture that has been chosen to improvethe legacy one, is based on the use of technologies, such as NFV and SDN. NFV consist onrunning several VMs in parallel on a cloud computing infrastructure, instead of using oneHW infrastructure per each network function. This means that the necessary number of HWin a virtualized network decrease. In order to deploy this, it needs a NFV architecture whichis represented in Figure 4.2. There are three main parts, the NFVI working domain, the VIM,and the FCAPS.
All these information is gathered in the pBOM document which is based on the vBOM,shown in previous lines.
5.1.1 NFVI PHYSICAL COMPONENTS
The NFVI Physical Components are divided into three parts: Physical compute, physicalnetwork, and physical storage [12]:
• Physical Compute
In order to run a VNF and its management components, it is needed physical compute.This physical compute is obtained by physical servers which provides resources likeCentral Processing Unit (CPU) and Random Access Memory (RAM). These servers arehosted in clusters, where each of them has its own workload type as well as its ownconfiguration.
Vodafone has chosen to use HP technology for the computing domain. In particular,they have been chosen the HPE c7000 Blade System since it has the best balance betweencosts and performance in the market.
Each enclousre is composed by the following elements, see Figure 5.3:
- HP BLc7000 Configure to order Platinum Enclosure with ROHS Trial Insight Con-trol License.
- HP BLc7000 Single Phase FIO Intelligent Power Module.
- HP 6X 2650W Platinum Hot Plug FIO Power Supply Kit.
- Six HP BLc Active Cool 200 Factory Integrated Fan Option.
- HP BLc7000 On-board Administrator with KVM Option (redundancy).
- Two HP Virtual Connect FlexFabric 20Gb/40 F8 Module.
- Two HP 6125XLG Ethernet switch to enable non-blocking network topology.
In addition, each enclousure is eqquiped with blades called HP ProLiant BL460c Gen9,see Figure 5.3. Each blade was configureted with the following specifications:
- CPU: Two CPUs (2.2 Ghz/20 cores per CPU).
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Figure 5.3: C7000 compute enclosure [12].
- RAM: Between eight and sixteen 32GB RAM, which means a total between 256GBor 512GB.
- Storage: It does not have a local Hard Disk Drive. The ESXi hypervisor is bootedfrom Storage Area Network (SAN).
Figure 5.4: HP ProLiant DL360p Gen9 [12].
• Physical Network
The physical network is divided into several layers: access, core and aggregation. Theaccess layer has switches, which provide network access to the blade servers whichare inside the enclosure. It interconnects blade servers, plugged in the enclosures, tothe external network via uplinks to aggregation layer. The core and aggregation layersprovide intra-track connectivity and aggregation for the access layer to the IP backbone.
For these layers, the HW used is the HPE 6125XLG Ethernet switches, see Figure 5.5. Itis used for VNFs workload traffic. The total number of HPE 6125XLG Ethernet switchesdepend on the configuration. In the case of a standard configuration, two HPE 6125XLGEthernet switches plugged in each enclosure is needed. However, in the case of using ahigh-performance configuration, four HPE 6125XLG Ethernet switches plugged in eachenclosure would be needed.
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Figure 5.5: HPE 6125XLG Ethernet switch [21].
• Physical Storage
In order to provide block storage to both physical and virtual infrastructures, it isnecessary to have a shared SAN. Each host that belongs to a hypervisor, is connectedto the same SAN infrastructure. Moreover, with the objective of providing optimumperformance, scalability and physical I/O separation, the Storage Area Network makeuse of a state of the art underlying infrastructure.
Due to the importance of having redundancy in storage, two separate Fabrics havebeen included. Each physical host has at least two FC HBAs (application programminginterface for host bus adapters), connected to two separate SAN switches.
Storage resources correspond to several Logical Unit Number (LUN)s, where each LUNhas 4 TB of size. This size was chosen keeping in mind the compromise between thesimplicity of management and the resilience requirements.
Following are listed the different layers of the Storage Area Network that were deployed:
– Fabric and SAN Switches
– Storage Array
– Storage Virtualization Layer
For optimal storage operation, all hosts in VIM management cluster should have accessto the same Datastore Cluster. Besides, in order to provide storage anti-affinity, allhosts in application management cluster and service cluster needs access to DatastoreCluster.
5.1.2 NFVI VIRTUAL COMPONENTS
As mentioned before, in the NFVI there are also virtual components, which are going to beexplained below [12]:
• Virtual Compute
Vodafone decided to virtualize its data core network by using VMware vSphere stack. Ithas two core components of vSphere which are ESXi and vCenter Server.
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ESXi is the hypervisor of the virtualized platform and it is in charge of abstractingphysical compute resources, into virtual resources. Furthermore, it allows to create andexecute VMs.
vCenter Server is the principal management element. It belongs to the VIM layer, andit is able to manage multiple hosts at the same time and connected it in a network.
All the physical compute hosts are gathering into vSphere cluster. This cluster is formedby ESXi hosts and VM with HW resources and a shared management interfaces.
• Virtual Network
Thanks to the combination between vSphere and VMware NSX, it is possible to obtainvirtual network resources. This is because, vSphere is able to provide the basic con-structs of virtual network interface cards and virtual switches, in order to achieve layer2 connectivity and switching.
VMware NSX can create, delete and restore SW based virtual network. The aim ofthese networks is it to provide communication between VNF components and to givedynamic control of their services.
NSX for vSphere gives a layer of abstraction by supporting an overlay network withstandards-based protocols. Thanks to this, the old network limitations are avoided.Furthermore, NSX is composed of three independent layers: data plane, control plane,and management plane.
• Virtual Storage
In order to provide virtual storage, external storage arrays are needed. vSphere supportsthird-party storage and provides enough capabilities to configure datastores out ofphysical storage LUNs.
5.2 NFVI MANAGEMENT
Figure 5.6 has an overview of the NFVI cluster management structure. In it, there are repre-sented three main clusters which are in charge of handling the NFVI, and the communicationsthat exist between them:
• Infrastructure Managemente Cluster: This cluster hosts the foundation components.Inside this cluster, two vCenter Server instances are running on NFV Infrastructure:
– The Management vCenter Server manages the Management Clusters, whereis the VNF manager called Cloud Service Manager (CSM). This VNF managerhandles the life cycle of VMs, and it can create, configure, and activate VMs, suchas vUSN, and vUGW among others VNFs.
– The Service vCenter Server manages the Resource Clusters, where is the vCloudDirector (vCD), which provides the interface, automation, and management fea-ture set to deliver vSphere resources to be consumed as a service.
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The reason why these two entities are separated is that it is easier to troubleshoot andto ensure the availability of the core management products in a dedicated cluster at alltimes.
• Application Management Cluster: This cluster hosts the analytics and element man-ager system components, such as PRS, U2000 and Virtual OSS Self-MaintenanceUnit (vOSMU).
• Data Service Cluster: Once the CSM creates the data plane components, such as vUSN,vUGW and Charging Gateway, among other, they are holded inside this cluster.
The following table gathers more information about these three clusters:
Cluster Workloadtype
vCPUres.
Managedby
vCD alloca-tion mode
Huawei VNFs
InfrastructureManagement
Infra Mgmt 60% MgmtvCenter
N/A CSM
ApplicationManagement
VNF Mgmt 60% vCD PAYG PRS, U2000,OSMU
Data ServiceCluster
VNF DataPlane
100% vCD ReservationPool
USN, UGW,CG
Table 5.1: vUGW and vUSN Connectivity Options [12].
Once the reader is familiar with all the parts of the NFVI and its elements in charge ofthe management, it is time to put them together and have a global vision of how they arestructured. Figure 5.7 represents how all the physical and virtual elements would be placedin their respective clusters and their connections with their respective switches.
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Figure 5.6: NFVI Clusters Management [12].
Figure 5.7: NFVI Physical and Virtual view [12].
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5.3 CONNECTIVITY DESING
This subsection provides a wide vision of the connectivity between the VNFs and the vEPC.Moreover, the VNF architecture of the most outstanding elements of the network are ex-plained, as well as the possible techniques for the routing of the input and output interfacesof the vEPC. In addition, possible problems and their solutions are identified for the designof connectivity.
Initially, two possible solutions were considered for the network architecture. These twooptions were focused mainly on the vUGW and vUSN nodes since these are the first nodes tobe virtualized and they have functionalities with important roles in the network.
Figure 5.8 shows the vUGW architecture in the Huawei vEPC (release 18.1). In it, it ispossible to differentiate two flows: One for Control Plane and the other for User Plane.Therefore, it is worthy to note that there are different VMs for each plane. For Control Plane,it is used the IPU interfaces and for User Plane, the APU interfaces.
On the right side of the frame, the green arrows represent the path that the signallingtraffic follows. This type of traffic leaves the IPU, and goes to the element that manages theControl Plane. Besides, IPU is responsible for the load balance of this flow. However, in thisrelease, it is within the VM managing the User Plane. Therefore, the user traffic is forwardedto VM which have the Control Plane related information. If the packets do not have therequired information of the Control Plane on the first VM that reaches, they will be sent tothe correct one, generating East-West (E/W) traffic.
Figure 5.8: vUGW Architecture [12].
In the case of the vUSN, there are only IPU VMs for managing the connectivity, sincethis node just forwards signalling traffic. The differences between vUGW and vUSN forconnectivity are reflected in the Figure 5.9. The image shows the inside of the HW HPC700where the nodes are configured. In it, there are the Virtual Network Interface Controller(vNIC)s used for both nodes, as well as the name of the logical interfaces connected to eachof them.
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Figure 5.9: vUGW and vUSN Interfaces [12].
The amount of mobile data plane traffic that these VMs have to handle is huge. Thisis why one single APU VM would not be enough. Hence, it is compulsory to use many ofthem working in parallel. However, the traffic in the Control Plane is quite lower, since thesignalling traffic has less amount of information.
Therefore, the number of APU boards needed is much higher than the number of IPUboards. For the first one, it can scale up to 100 VMs, while for the second would be enoughjust using 2 VMs.
In order to ensure that all these packets are forwarded to the vEPC, it has to be used atraffic load balancing between the APU and IPU. The VMs have different logical interfaces,for instance, S1-MME, S11, S5/S8, Gx, Gy, Gi, among others. Each of these interfaces hasdifferent scalability requirements. So, it is possible to implement several networking options,taking into account these scalability requirements [30].
The Table 5.2 lists the association of networking options and their possible logical inter-faces, as well as VM applicable:
VNF VMType
Number ofVMs
Logical interfaces Type of Traffic NetworkProtocol
vUSN
IPU 2 S1-MME Control OSPF/StaticIPU 2 Gb Control OSPF/StaticIPU 2 S11/S10, Gn, Gp, Iu-U Control OSPF/StaticIPU 2 Gr, S6a, SGs, Ga, Iu-C Control OSPF/Static
vUGW
APU N S1-U Data OSPF/BGPAPU N S11, S5/S8, Gn, Gp, IuPS Data OSPF/BGPAPU N Gi Data OSPF/BGPIPU 2 Gx, Gy, Ga, Radius Control OSPF/Static
Table 5.2: vUGW and vUSN Connectivity Options [12].
In order to implement the connectivity of the IPU VM and being compliant with the load
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balancing requirements, two possibilities were evaluated:
• The first option is reflected in Figure 5.10, where, to simplify the scheme, it is repre-sented by a single logical interface and two examples of routers, R1 and R2. For thisscenario, is required a common VLAN which joins routers and the IPU using OpenShortest Path First (OSPF). This option uses service IP addresses, which are announcedby OSPF (this service IP addresses, are logical interfaces which correspond to destina-tion addresses). Hence, the router knows them, since the traffic comes from both IPU.So, the routers implement two ways Equal-Cost Multi-Path (ECMP) routes. The strategyusing ECMP is to forward the packets to a single destination over multiple possible bestpaths, which have the same values in the calculation of routing metrics. This providesmore bandwidth thanks to load-balancing the traffic over these multiple best paths.However, OSPF has some limitations in terms of scalability that have to be taken intoaccount [6].
Figure 5.10: Option One. Implementa-tion of Connectivity for the IPU VM type[12].
Figure 5.11: Option Two. Implementa-tion of Connectivity for the IPU VM type[12].
• The second option has the same principle but using static routes to forward the trafficto the IPU. Figure 5.11 represents the scheme of this alternative. There are two routerswith static routes for each service IP address. The main problem with this option is thatit requires manual configuration. In addition, it does not have an automatic scalabilityin case of needing more IPU in the future. This would limit the growth of the networkfor future applications.
In order to ensure not to sent traffic to a black-hole next-hop after one IPU fails,BidirectionalForwarding Detection (BFD) protocol has to be used in both options. This protocol can detectforwarding path failures fast enough so that the efficiency of the network is not affected [5].
After evaluating the pros and cons of each of the possibilities, the first options was chosen.Even though OSPF brings some limitations that make not be possible to use it in some situa-tions, option two has more disadvantages that in the long term, would affect seriously theexpansion of the network.
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In the following lines, it will be evaluated the connectivity options for the data planeinterfaces. As was explained before, the traffic is quite higher through the APU VM than forthe IPU VM. In order to manage this traffic, it can be done by implementing two optionsshown below in Figures 5.12 and 5.13.
Figure 5.12: Option One. Implementa-tion of Connectivity for the APU VM type[12].
Figure 5.13: Option Two. Implementa-tion of Connectivity for the APU VM type[12].
In order to simplify the scheme, these images have only four APUs. However, a realdeployment would have a higher number of these interfaces. The quantity would depend onthe amount of traffic to be managed. In addition, two routers are represented as an example,R1 and R2.
In both cases, it is possible to use OSPF routing protocol, since it provides enough scalabil-ity and deployment automation. Therefore, it would be necessary to adapt the configurationon the router side, when a change in the network topology occurs. Hence, this is a featurethat must be taken advantage of.
• In the first option that was raised, each of the vNICs used for each APU, was associatedwith the same common VLAN, as it is shown in Figure 5.12. This VLAN is in themiddle of the application and the routers. In addition, it was considered that thevEPC could have a loopback IP (Lo_vEPC), so a Border Gateway Protocol (BGP) sessioncould be implemented. This would allow the routers to see the IP of the Access PointName (APN) pool addresses and the GTP Tunnel endpoints. Hence, the routes canknow the destination IP as BGP routers with a next hop to the vEPC (Lo_vEPC). In thisoption, it is used OSPF to propagate the loopback IP, instead of using static routes. Inaddition, OSPF is used to implement the load balancing for the APU by using (ECMP).This is due to the routers have a set of OSPF ECMP routes equal to the number of APU.
However, although this solution may seem optimal, it must bear in mind that thereare some situations where OSPF cannot be used. The solution would be the use ofstatic routes, so the routers need to be manually configured with a set of static routes.All these routes would have the same destination address, which is, in this case, theloopback IP on the vEPC. Furthermore, the next-hop would be each IP address of theAPU on the common VLAN. Therefore, the load balancing would be made by ECMP
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instead of OSPF. Nevertheless, implementing a manual configuration is not the bestapproach, since there may be a large number of these routes making it not scalablesince the number of routers follows the following equation:
Number o f Routes = Number o f Log i cal Inter f aces §Number o f APU (5.1)
• Second option is simpler than the first one, since the BGP session is removed and theservice IP addresses are announced directly by OSPF. This allows the routers to seethese IPs coming as OSPF routes from the APU as next-hop. All these routes wouldhave the same metric. The implementation of load balancing is done by OSPF ECMP,as it happens in the option number one.
One of the failure cases that should be considered is the down of a VM or interfacesassociated to any vNIC of a IPU. During this scenario, the router could not forward the trafficto the next-hop. Thanks to the use of OSPF it is possible to fix the problem in around 1 minutesince this protocol has its own convergence mechanism which can remove or add neighbours.However, the time needed by OSPF to solve the failure is not always acceptable. This is whyin some situations is more optimal using BFD protocol which is able to faster recalculatingthe new routes to reach the next-hop. To do this, it is assumed that it is possible to bind asingle BFD session to all the interfaces and vNIC of an IPU. If not, there is a scalability issuebecause it would need to have a BFD session per each interface.
With the intention of understanding better which option is the most successful, thefollowing Table 5.3 has some general considerations of scalability to take into account.
Paremeter Value
VLAN x+yECMP routes per UP interface nECMP routes per CP interface 2Total ECMP routes n*x +2*yTotalBGP session (option 1) x+yTotal BFD session (one per interface) n*x +2*yOSPF neighbours per UP interface nTotal OSPF neigbours n*x +2*y
Table 5.3: Network parameters dimensioning [12].
Where:
- 2: is the number of IPU
- n: is the Number of APU
- x: is the Number of Logical UserPlane Interfaces
- y: is the Number of Logical Con-trol Plane Interfaces
After considering the two options, option number two was chosen. The main reasonswere that it does not need so much configuration since BGP session is not used. In addition,it is not using a routing reverse lookup, so the implementation is easier.
Once the design of the connectivity has been chosen, it was necessary to consider otherpossible limitations in vUGW. For instance, one of the main issues that were taken intoaccount, was the topic of: How many neighbours could support OSPF?.
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As we have seen previously, the more capacity the vUGW has, the greater number of APUsare necessary. Therefore, OSPF would have to support a greater number of neighbours. Butthere are limitations, these neighbours cannot be too many since the load has to be balancedbetween them. This reasoning can be explained with the following formula:
OSPF nei g hbour s +BF Dsessi ons = Number o f APUs §Number o f user pl aneV RF(5.2)
Now, let’s consider a more concrete example:
90APUs §3V RF s(Gi ,Gn,S1°U ) = 270 (5.3)
Which means, there would be 270 OSPF neighbours per router. This amount is not contem-plated by the manufacturers, so it would be a risk to implement it. Therefore, the decision wasmade to lower the number of APUs, and this results in less capacity in the vUGW. Specifically,it was agreed to reduce the number of APUs to 70, which translates the throughput to 70%instead of 90%, as was originally intended.
However, although the capacity is reduced, it is not a problem taking into account thearchitecture of the rest of the data core network. Actually, there are 8 APUs of redundancy:62+8. Although these 8 VMs will not work correctly, all the traffic that is estimated to haveinside the node could go through the remaining 62 APUs without problems. In order to seemore information about the traffic estimation, go to Section 2.3.
5.3.1 LLD
In this part, it is presented the LLD, where are shown in a technical way the connectivitydecisions that have been taken in section 5.3.
Note, that for reasons of confidentiality, in this project it has been preferred not to includeIP addresses, masks or any other data that could be sensitive to the security of the Vodafonenetwork.
As already shown in previous sections, the vUSN is a node which has just IPU VMs. On thecontrary, the vUGW not only has IPUs for signalling but also has to use APU VMs to managedata traffic. Each of these VMs has a vNIC assigned that, at the same time, has an allocatedinterface. In order to know how to carry out these relationships, the following list containsthe rules which relate vNICs to their respective interfaces:
• vNICs 0,1 and 2: Internal traffic.
• vNIC 3: Access interfaces. Gb, lu, S1-MME for vUSN and S1-U and Gn/S11 for vUGW.
• vNIC 4: Interfaces to the data core network, or Internet. Gn/S11 and S1-U for vUSNand Gi for vUGW.
• vNIC 5: Signaling interfaces and others. Rest of interfaces for vUSN and signalinginterfaces for vUGW.
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To avoid possible failures, the same vNIC is assigned to two VM: IPU1-IPU2, APU1-APU2.Thanks to using this redundancy, if one of the two VMs fails, there would always be anotherthat would replace it. So the data traffic would not be affected.
Once these relationships are done, it remains to assign sub-ports to each vNIC, as well asVLAN ID and VPN Routing and Forwarding (VRF). All these information is reflected in Figure5.14 for the vUSN and 5.15 for the vUGW. There, it is shown not only their VM, ports andsub-ports but also the logical interfaces and the networking that has been chosen for each ofthem.
These two figures are very useful when configuring the NEs, since the tables have datathat must be entered in each of the nodes to integrate them into the data core network. Inorder to know more information about configuration, go to the following section 5.4.
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Figure 5.14: vUSN IP Desing.
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Figure 5.15: vUGW and vMSE IP Desing.
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5.4 INSTALLATION AND CONFIGURATION
This section describes the steps carried out in order to make the installation and configura-tions of several NEs that were introduced in Section 4.2, and 5.2. All the stages were made inthe laboratory at Vodafone Plaza, in Madrid.
As it has been explained in section 4 and 5.2, there are three types of clusters in a virtualenvironment. One is the Infrastructure Management Cluster, and it holds the CSM and vCD.Another one is the Application Management Cluster, which gathers elements for analytics,such as vOSMU, U2000 and PRS. Furthermore, there is the Data Service Cluster, where arethe VNF.
To virtualize the network, it is necessary to create and apprropriately manage all theseelements. With this purpose, all of them have to be installed following a strict order, markedby the manuals of VMware and Huawei.
First of all, it has to be created the CSM by using descriptor files. This element is veryimportant since it is in charge of the creation of the VNFs. For this reason, it should be verifiedthat after its creation, it has communications with the other components as, vOSMU, vCDand vCenter. In order to carry out this check, a computer network software called ping wasused. This software tool allows testing the reachability of a host on a IP network.
During this step, it was found that the CSM and the services cluster did not have commu-nication. So, the LLD of the vUSN and vUGW (see Figures 5.14 and 5.15) were first checkedto verify that the connectivity was correct.
Once it was ruled out that it was a connectivity problem, the next step was to check thefirewall rules. This checkup showed that there were some rules missing from the Managementand the Services vCenters. In order to solve this fault, the firewall rules were reconfigured,taking into account the IPs that had not been added from the beginning.
After solving this problem, the next step was to transfer the descriptor CSM files, whichhave the VNFs. This transfer is made through a File Transfer Protocol (FTP) session, from theCSM in the Management vCenter to the vCloud in the Service vCenter. After these descriptorfiles were installed there, the NFVs can start to be created.
The installation is made with a Huawei SW, where it is possible to place all the features ofeach node that were agreed in previous steps in the vBOM and LLD, in Sections 5.1 and 5.3.1respectively.
During this process, the redundancy of the VMs was taken into account. Hence, for eachVM required, it was created two of them. One as VM master and the other as VM slave. Noticethat each of them have a different IP address.
During the creation of the vUSN, it was found that there were several master and slaveVMs with the same IP address. This issue was solved stopping the creation process andstarting it again.
For the configuration of the NEs, it is necessary to differentiate between its internal, and itsexternal part. The configuration that will be shown next, refers to the external part whichhas the interfaces that are used for the integration of the nodes with the rest of the data corenetwork. (It has been decided to show only the external configuration since this part has
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more relation whit the topic of this thesis).Then several commands used in the configuration will be listed. These commands are in
their most generic form to not show data that could be confidential. Note that only the mostrelevant commands have been included since the configuration files are very large and notall could be displayed:
• Set global BFD attributes:
SET BFD:BFDENABLE=TRUE;
This command enables a BFD session for each of the interfaces of the nodes whichuses BFD.
• Add an Layer 3 Virtual Private Networks (L3VPN) instance:
ADD L3VPNINST:VRFNAME="vrf1";
This step adds a dedicated Virtual Private Network (VPN) for each of the interfaces.Althoutg a VPN cannot share resources with other VPNs on the same network, it is ableto protect internal information, this is why add this element is important.
• Add IP address family:
ADD VPNINSTAF:VRFNAME="vrf1", AFTYPE=ipv4uni;
This command is used to add an IP address family to each L3VPN instance.
• Add associations between interfaces:
ADD IPBINDVPN:IFNAME="Loopback1",VRFNAME="vrf1";
This command is used to associate an interface connecting to the VPN with the VPNinstance. So, this interface is used as a private network interface on which a privatenetwork address and a private network routing protocol can be configured.
This command is used to configure an IPv4 address for a logical or physical interface.
5.5 SW VALIDATION
In this section it is shown how to validate different NEs: vUSN, vUGW, and its homonyms in5G: CGW and DGW.
The section is divided into two parts. First, a case guide with a generic list with the mostrelevant uses cases that were tested and a brief explanation of it. And after, it will be presentedthe result of these tests.
Although all these tests were carried out and are part of the technical section of thisproject, notice that just three cases will be presented. The idea is to give the reader a clearpicture of how are these tests, without adding more cases lengthening the content of thisthesis.
5.5.1 CASES GUIDE
During the NEs’ validation, a series of tests were carried out to verify the correct functioningof each element. Below is a list of all the tests that were performed on the vUSN in 3G [14],vUSN in 4G [15], and vUGW [16]. Furthermore, the use case for the 5G tests is also brieflyexplained.
The following cases guide was proposed by Huawei and is based on the 3GPP possiblescenarios that each NE could face in the future. The idea is to test all these scenarios puttingmore emphasis on those more important and critical. With this, it pretends to ensure thecorrect functioning of each node and validate it.
Notice that for each test it was necessary to reconfigure each node in such a way that theywere ready for each of the tests.
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vUSN uses cases in 3G # vUSN uses cases in 4G #
Basic Services 1 Subscription Management 2Mobility Management 8 Mobility Management 12Security Management 8 Security Management 9Subscriber Data Management 3 Session Management 10Session Management 8 Interface Management 7Charging Function 3 Handover 2QoS and Flow Management 3 MME Pool 3QoS Control 3 QoS Mapping 1QoS Conversion 1 IMSI Based QoS Control 1HSPA 11 QoS Control Enhancement 13G Subscriber Access Control 1 Auto-Configuration of the X2 Inter-
face1
Area Roaming 1 NE Selection 8Network Reselection between LTEand UMTS
1 Access Control 2
PS Handover Between LTE andUMTS
1 GUL Interworking 3
Multi-HPLMN Function 1 Non-EPS Alert 1Detach of Inactive Subscribers 1 Telecom Service 15Idle PDP Context Deactivation 1 CSFB with MSC Pool 1Iu-PS Interface 1 Requested APN Correction 1SS7 Interface 2 Multiple HPLMNs 1Ga Interface 1O peration and Maintenance 9Gn Interface 1Emergency Call 1Gateway Route Selection 6 Accurate Paging 1Requested Information Correction 1 Interoperation Between the LTE
and WiFi Networks1
IMS 1 Voice Policy Control for User Group 3Gs Interface 3 Location Information Query in
Voice Service1
Subscriber Migration in MSCPOOL
1 Local QoS Policy in PCC Mode 1
Iu-Flex 3 Category Function 4SGSN Pool 1 IP Function 6ODB 1 Support eNodeB Coverage Level
Based Paging1
Multi-IMSI Function Test 1 LTE M2M Terminal Power Saving 1Direct Tunnel 1 Presence Reporting Area Support 1NACC 1 Low-Priority Access Control 1Network Share MOCN 1 Signaling Congestion Control
Based on the Back-off Timer1
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IMEI Check for Gf Interface 1 Equivalent NE Selection Based onLocation
1
vUSN Life Cycle Management 2 LTE PTT 1CHR 1 Network Interoperation Between
CDMA2000 and LTE1
Extended Periodic RAU/TAU Timerfor M2M
1 PDN Re-Activation to Local P-GW 1
APN-based Signaling CongestionControl
1 HeNB’s Access to the MMEThrough an HeNB Gateway
1
Null-MSISDN Function Supportedby the SGSN
1 LTE UE Signaling Control 1
S4 SGSN Project Acceptance 2 End-to End Subscriber Trace 1Service-based Handover 1 CBS 1Multi-Signaling 1 Network Identity Selection Based
on RAN Area1
Smartphone Control 3 Service Guarantee for High-Mobility User
For the validation of 5G in NSA, as it has never been tested before, there is no list ofevidence to follow. For this reason, the tests that were carried out were with the simplestscenarios, checking the correct functioning of the Basic Services and Mobility Managementtest. See more details about the testing phase, going to Appendix C.
5.5.2 ENVIRONMENT SETUP
To make the SW validation of the different NEs, it was previously necessary to make a setupof the environment. So, the procedure that was carried out for the validation of the vUSN and
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vUGW #
Operation and Maintenance 29Routing And Network 10Basic Services 21Radius Management 11Charging Management 3TOTAL: 74
Table 5.5: vUGW uses cases [16].
vUGW nodes will be explained, and later it will be shown how the environment was adaptedfor the NSA tests.
For the vUSN and vUGW the tests were carried out in the laboratory, at Vodafone Plaza inMadrid. The elements that were used are:
• Smartphone compatible with 2G/3G/4G technologies.
• Subscriber Identity Module (SIM) cards compatible with 2G/3G/4G technologies.
• Faraday cages.
• Cables with 2G/3G/4G signals.
• Laptops with the operative system: Windows 10.
• SW to trace messages: Wireshark and TraceViewer (SW from Huawei).
• Remote access from the PC to the nodes through browsers.
• Laptop and smartphone chargers.
• 2G/3G/4G antennas placed in Vodafone Plaza, pointing to the testbed Gi-LAN (whereare placed all the platforms).
Once all the material have been gathered, we need to place the SIM card in the smart-phone. Both SIM and smartphone should be compatible with 2G/3G/4G technologies toavoid problems in any of the tests.
The first step is to initiate the SW from Huawei with which the messages sent betweenthe device and the network are traced to control its operation. To do this, once this SW hasbeen initialized, certain parameters must be entered. For instance, the International MobileSubscriber Identity (IMSI) of the UE, so that it only traces the messages sent from that deviceand does not mix with others.
After that, the smartphone is powered on, and it checks that it works correctly. In addition,the smartphone is placed in the Faradays’ cage, see Figure 5.16. The device is placed there,because thanks to the effect of the Faraday cage, the electromagnetic field inside is zero. So
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the effect of external fields is cancelled. Therefore, there are connected to the cage cableswith 2G/3G/4G signals pointing to the testbed line, forcing the phone to connect to one ofthem, without being affected by external signals. This is very important since the vUSN andvUGW nodes are only located in the testbed line. Hence, if the mobile is connected to anothersignal that is not the testbed, tests could not have been carried out. Figure 5.17 shown theconnections of the Faraday cage where they are connected in that case, cables with 3G and4G signals.
Once the Faraday cage is provisioned with signal pointing to the testbed, it is time toactivate the Airplane Mode to the phone. This is done to avoid being connected to othersignals. After this, it is closed almost completely the door of the cage, leaving a small space forthe hand, which will deactivate the Airplane Mode, and subsequently close the cage quickly,see Figure 5.18.
Later, a small interval of time is left for the mobile to be attached to the network that hasmore power in the cage. Then, in order to check that the phone is attached to the correspond-ing network, it is possible to look through the metal mesh and verify that everything worksproperly. Figure 5.19 has an image with the mobile inside the cage, where the network withwhich the UE is attached, is LTE.
Finally, the SW validation can start. Go to Subsection 5.5.3 to see more information aboutthe procedure to follow and some of the tests carried out, as well as its results.
Figure 5.16: Step One - Placement of thetest mobile in the Faraday cage.
Figure 5.17: Step Two - Cables provision-ing 4G and 3G signals to the Faradaycage.
In the case of the NSA testing, the environmental setup was different. The elementsneeded, were the following:
• SW to trace messages: Wireshark and TraceViewer (SW from Huawei).
Figure 5.18: Step Three - Cage of Faradayclosed, with the mobile test inside, readyto begin the tests.
Figure 5.19: Step Four - Monitoring ofthe test mobile signal through the meshof the Faraday cage.
The equipment was placed outdoor, in Vodafone Plaza installations. First of all, twoantennas were installed in one of the corners of the building. One transmitting and receiving4G signals, and the other for 5G transmissions. Figure 5.20 has a photography of theseantennas. Both antennas are needed since it was a NSA test, where the data goes through 5Gbut signalling through 4G. See more information about this topic in Subsection 4.3.3 .
In addition, the CPE was also placed in Vodafone Plaza, as it is shown in Figure 5.21. Inorder to achieve the best results in the test, several measurements of coverage were carriedout inside the courtyard. Once the place with the best coverage values was found, the testswere started. See Section 5.5.3 to find more information about this tests.
Figure 5.20: 5G and 4G antennas for NSAtesting, in Vodafone Plaza.
Figure 5.21: NSA Testing - Huawei CPEside, in Vodafone Plaza.
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Figure 5.22: Huawei CPE: First Commercial 5G Modem, [10].
5.5.3 RESULTS
Following, three results of the tests based on the previous section will be presented. Being somany tests, and with very long visual results, it has been decided to put only the most relevantcases of each node and each technology. This is why the results shown below are from vUSNusing 3G technology, vUGW in 4G, and the nodes DGW and CGW using 5G technology, in thearchitecture NSA:
T01-02 Combined Attach
T01-0201 UE Initiating a Combined Attach Procedure
A combined attach is a double attach used for Evolved Packet System (EPS) and for non-EPS(e.g. Short Message Service (SMS) only). Moreover, it is also used by UE in Circuit Switch-ing (CS) and Packet Switching (PS) to attach for EPS services when the IMSI it is alreadyattached for non-EPS services. The purpose of doing this test is to verify that the MMEsupports the combined attach procedure. In addition, it is also used to see if the MME canmap a Tracking Area Identity (TAI) and a Location Area Identity (LAI) to the Mobile switchingcenter (MSC)/Visitor Location Register (VLR). With this, the idea is to find the MSC/VLRconfiguration which is based on the LAI since it can be used to provide CS services for thesubscribers.
The following diagram, in Figure 5.23, represents the normal behaviour of a combinedattach based on the 3GPP standards. In it, there are all the messages that are needed to besent between the NEs, in order to complete with success the combined attach. Therefore, tobe sure that everything was working properly during the test, the results were compared withthis procedure.
Before start the testing, it is necessary to preset some parameter conditions:
• The UE should be subscribed in the EPS and CS services.
• Activation the license to support for voice, via CS-Fallback (CSFB) with the followingMan-Machine Language (MML) command:
SET LICENSESWITCH: LICITEM="LKV2CSFBGU02", SWITCH=ENABLE;
• MME configuration: set SGs links and map TAIs and LAIs
• To check if the subscriber information is already registred in the MME:
DSP MMCTX: QUERYOPT=BYIMSI, IMSI="<IMSI>";
• Creation of user, S6a interface, S1 interface, SGs, and GTP-C tracing tasks in the MME.
Once these preset conditions were covered, the UE was powered on. Besides, it wasplaced in the Faraday’s cage, with a 4G coverage by following the environment setup, alreadyexplained in Subsection 5.5.2.
The resulting traces of this test, are displayed in Figure 5.24. In this image, there are allthe messages which were sent between the platforms. It is indicated the traces number, thetime, the position, and the message body length. In addition, it is also indicated from whichnode comes the message, as well as which is its the destination. Another important data thatis in this image, it is the message type.
The three most important data are time, message type and message direction. Therefore,in order to identify if the test was carried out correctly, these three fields were checked out bycomparing it with the expected behaviour, Figure 5.23.
73
CH
APT
ER
5.D
EPLO
YME
NT
Figure 5.24: T01-0201 Combined Attach Traces.
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In this particular case, the test was successful. In the following lines, there is a list with allthe messages forwarded with a brief explanation of each of them (the messages correspondingto the internal traffic of every node have not been evaluated). Notice that the numbers ofeach listing element correspond to the number of each message represented in Figure 5.24:
[442 ] After powered on the UE, the device sent a Attach Request message to the MME. Thismessage had the attach type IE whose value is "combined attach".
[443 ] The next message is a Identity Request. Here, the UE is identified in the MME.
[444 ] The UE sends a Identity Responds to the MME, with its identification.
[445 ] In the following trace, the MME ask to the Home Subscriber Server (HSS) about theuser profile of the specific UE to request security vectors. Therefore, inside this message,it is send an Authentication Information Request, with the IMSI of the UE .
[446 ] After, the HSS returns to the MME an Authentication Information Answer message,that holds the EPS security vectors.
[447 ] As a result, the MME sends its Authentication Request message to the UE, with theAUTH and RAND IEs.
[450 ] In responds, the UE sends an Authentication Response message to the MME.
[451 ] The next trace is the MME sending a Security Mode Command message to the UE. Init, there is a negotiation about the key and algorithm to be used.
[454 ] As a consequence of this last message, the UE sends a Security Mode Complete messageto the MME.
[455 ] Once this last exchanges of messages end, it is time to send an Update LocationRequest message, from the MME to the HSS. Thanks to this message, it is possible toupdate the location of the UE since it holds the ULR-Flags IE. These flags indicate tothe HSS that has to include a subscription data in the next Update Location Answermessage to be returned.
[456 ] Then, the HSS brings back an Update Location Answer message, where it is includedthe subscription data required.
[461 ] Later, the update process is complete. Hence, the MME is ready to starts a defaultbearer establishment procedure. For it, it is sent a Create Session Request message tothe S-GW. Inside this message, there is the P-GW IP address to which the S-GW pointsand the Evidence-Based Intervention (EBI) IEs. In response, the S-GW takes care offorwarding the Create Session Request message to the P-GW.
[462 ] So, as a consequence, the P-GW returns a Create Session Response message to theS-GW. This message contains the control and user plane IPs, as well as the TunnelEndpoint Identifier (TEID) and charging ID of the P-GW. This last message is forwardedby the S-GW to the MME.
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[465 ] Finally, the MME forwards, a Initial Context Setup Request message, which contaisn anAttach Accept message, to the eNodeB. This Attach Accept message carries an ActivateDefault EPS Bearer Context Request message. The UE returns an Attach Completemessage and the eNodeB forwards an Initial Context Setup Response message. Withthis message, it is indicated the setup of the default bearer.
[443 ] The next message is a Identity Request. Here, the UE is identified in the MME.
[444 ] The UE sends a Identity Responds to the MME, with its identification.
[445 ] In the following trace, the MME ask to the HSS about the user profile of the specific UEto request security vectors. Therefore, inside this message, it is send an AuthenticationInformation Request, with the IMSI of the UE .
[446 ] After, the HSS returns to the MME an Authentication Information Answer message,that holds the EPS security vectors.
[447 ] As a result, the MME sends its Authentication Request message to the UE, with theAUTH and RAND IEs.
[450 ] In responds, the UE sends an Authentication Response message to the MME.
[451 ] The next trace is the MME sending a Security Mode Command message to the UE. Init, there is a negotiation about the key and algorithm to be used.
[454 ] As a consequence of this last message, the UE sends a Security Mode Complete messageto the MME.
[455 ] Once this last exchanges of messages end, it is time to send an Update LocationRequest message, from the MME to the HSS. Thanks to this message, it is possible toupdate the location of the UE since it holds the ULR-Flags IE. These flags indicate tothe HSS that has to include a subscription data in the next Update Location Answermessage to be returned.
[456 ] Then, the HSS brings back an Update Location Answer message, where it is includedthe subscription data required.
[461 ] Later, the update process is complete. Hence, the MME is ready to starts a defaultbearer establishment procedure. For it, it is sent a Create Session Request message tothe S-GW. Inside this message, there is the P-GW IP address to which the S-GW pointsand the EBI IEs. In response, the S-GW takes care of forwarding the Create SessionRequest message to the P-GW.
[462 ] So, as a consequence, the P-GW returns a Create Session Response message to theS-GW. This message contains the control and user plane IPs, as well as the TEID andcharging ID of the P-GW. This last message is forwarded by the S-GW to the MME.
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[465 ] Finally, the MME forwards a Initial Context Setup Request message to the eNodeB,which contains an Attach Accept message. This Attach Accept message carries an Acti-vate Default EPS Bearer Context Request message. The UE returns an Attach Completemessage and the eNodeB forwards an Initial Context Setup Response message. Withthis message, it is indicated the setup of the default bearer.
After having seen the exchange of packages between the different NEs that are involvedin a combined attach, it is time to analyze one of these packages to verify that its content hasall the parameters and their correct values.
Since the information that a trace holds it is quite large, it was decided to simplify andexplain just one of them to have a general vision about its structure, parameters and values.
The message number [442] with an Attach Request, is the packet which contains thelargest amount of information during the combined attach. This is why it was selected as themessage to be explained coming up next.
Trace 5.1 has part of the content of this message. Coming up next, there is a brief explana-tion about the content of this trace. Since each line of the trace is assigned to a number onthe left side, this reference will be used to comment on that line:
[28-48 ] Indicates that the Internet Protocol used is in Version 4. In addition, the most relevantparameters used for IPv4 are shown. For instance, header length, checksum, time tolive, and the Stream Control Transmission Protocol (SCTP) protocol used.
[51-59 ] The S1 Application Protocol have parameters between the MME and eNodeB. Inside,there is the EPS mobile identity field which has information with regards the MobileCountry Code (MCC) and the Mobile Network Code (MNC). Both parameters havedata about the UE location (e.g. MCC equal to 214, means that the UE is in Spain. Inaddition, if the MNC is equal to 01, means that the mobile operator used is Vodafone).Moreover, there are also data about the MME group ID, MME Code and M TemporaryMobile Subscriber Identity (M-TMSI), which gather values that indicates in which MMEwas attached the UE for last time. All these information has relation with the GlobalUnique Temporary Identityl (GUTI).
[60-93 ] Inside the UE network capability there are several parameters which indicate theencryption that the UE supports. When the bits are set to 1, means that the service issupported. However, if it is set to 0, it is not supported by the device.
[97-100 ] ESM message container content gathers information about the EPS bearer iden-tity.
[101-103 ] In addition, there are Non-Access Stratum (NAS) EPS session managementmessges. Here, there are information about the Packet Data Network (PDN)connectivity.
The reason for the existence of this field is a need in LTE to have an open contextwhenever it is being attached. When the device receives a call on LTE, it must
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change the network to one of 3G/2G, doing CSFB. Once the call has finished, theUE must go back to 4G. And for this whole process, it is necessary to have an opencontext all the time.
The disadvantage of using this technology is that the battery of the device is spentmuch more easily. But the advantage is that the UE is connected all time, receivinginstant notifications.
[101-103 ] In the ESM information transfer flag, there are information about the APN. Whenthe bit is set to 1, it is the network which select the APN by default: airtelwap.es.However, if the bit it is 0, the APN is selected by the UE.
[121-125 ] Tracking area identity. The elements inside this packet, indicate to the MME the lastlocation of the UE. The idea is to know where was the last connection of the device.
If the MME wants to get in touch with the device, it has to paging the UE eNodeB. But ifthe device does not answer, the MME will send paging messages to all the eNodeB ofthe TAI where the UE was connected for the last time, until finding it.
[126-131 ] The DRX Parameters are in charge of saving battery. These values indicate how muchtime the radio bearer can be on.
Here it is important to differentiate between context and bearer. The context anchorsthe device in a unique way. However, the bearer can be assembled and disassembledaccording to the needs required by the UE. Therefore, in order to save energy, when theradio carrier is not necessary, it is dismantled. And the parameter that indicates whento deactivate it is:
[128] SPLIT PG CYCLE CODE: 10 (10)
[133-159 ] The MS Network capability indicates the capabilities via dedicated channels of theterminal to do handover and Single Radio Voice Call Continuity (SRVCC).
[161-164 ] Temporary Mobile Subscriber Identity (TMSI) Status. The TMSI is used in pagingsituations and it is incharge of protect subscribers of being identificated. TMSI is holdby VLR and is not passed to Home Location Register (HLR). Besides, The TMSI is storedin the SIM.
request (0xd0)102 0001 ... . = PDN type : IPv4 (1)103 ... . 0001 = Request type : Initial request (1)104 ESM information transfer flag105 1101 ... . = Element ID : 0xd -106 ... . 000 . = Spare bit (s): 0 x00107 ... . ...1 = EIT ( ESM information transfer ): Security ...
protected ESM information transfer required108 P-TMSI Signature - Old P-TMSI Signature109 Element ID: 0x19110 P-TMSI Signature: 0xa0d73b111 EPS mobile identity - Additional GUTI112 Element ID: 0x50113 Length: 11114 ... . 0 ... = Odd / even indication : Even number of identity ...
digits115 ... . .110 = Type of identity : GUTI (6)116 Mobile Country Code (MCC): Spain (214)117 Mobile Network Code (MNC): Vodafone Espana , SAU (01)118 MME Group ID: 32769119 MME Code: 192120 M-TMSI: 0xe40d21eb121 Tracking area identity - Last visited registered TAI122 Element ID: 0x52123 Mobile Country Code (MCC): Spain (214)124 Mobile Network Code (MNC): Vodafone Espana , SAU (01)125 Tracking area code(TAC): 264126 DRX Parameter127 Element ID: 0x5c128 SPLIT PG CYCLE CODE: 10 (10)129 0000 ... . = CN Specific DRX cycle length coefficient : CN ...
Specific DRX cycle length coefficient / value not ...specified by the MS (0)
130 ... . 0 ... = SPLIT on CCCH : Split pg cycle on CCCH is not ...supported by the mobile station
131 ... . .000 = Non - DRX timer : no non - DRX mode after ...transfer state (0)
132
133 MS Network Capability
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CHAPTER 5. DEPLOYMENT
134 Element ID: 0x31135 Length: 3136 1 ... .... = GEA /1: Encryption algorithm available137 .1.. ... . = SM capabilities via dedicated channels : Mobile ...
station supports mobile terminated point to point SMS ...via dedicated signalling channels
138 ..1. ... . = SM capabilities via GPRS channels : Mobile ...station supports mobile terminated point to point SMS ...via GPRS packet data channels
139 ... 0 .... = UCS2 support : The ME has a preference for the ...default alphabet ( defined in 3 GPP TS 23 .038 [8 b ]) over UCS2
140 ... . 01 .. = SS Screening Indicator : capability of handling ...of ellipsis notation and phase 2 error handling (0 x1 )
141 ... . ..0. = SoLSA Capability : The ME does not support SoLSA142 ... . ...1 = Revision level indicator : Used by a mobile ...
station supporting R99 or later versions of the protocol143 1 ... .... = PFC feature mode : Mobile station does support ...
155 ... 1 .... = ISR support : The mobile station supports ISR156 ... . 0 ... = SRVCC to GERAN / UTRAN capability : SRVCC from ...
UTRAN HSPA or E - UTRAN to GERAN / UTRAN not supported157 ... . .1.. = EPC capability : EPC supported158 ... . ..0. = NF capability : Mobile station does not support ...
the notification procedure159 ... . ...0 = GERAN network sharing capability : Mobile ...
station does not support GERAN network sharing160
161 TMSI Status162 1001 ... . = Element ID : 0x9 -163 ... . 000 . = Spare bit (s): 0164 ... . ...0 = TMSI flag : no valid TMSI available
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T01-11 Gy Interface Online Charging on the P-GW
T01-1101 Real-Time Charging for User Services
Online charging is a real-time mechanism which is an extension of call accounting. Thismechanism enables to apply rules for user rating and control the network resources. So,depending on the services that are consumed, the user will have a rate or another, includingpromotions and discounts. The goal of using online charging is to better personalize thetelecom experience of the customers.
It is very important for Vodafone that this test is approved successfully, since a large partof its services with Vodafone Pass, are based on the user rating: Video Pass, Music Pass, MapsPass, Social Pass. See more details in the Section 4.2.1.
The technical aim doing this test, is to verify that the vUGW, functioning as a P-GW,supports the volume-based Call Detail Record (CDR) generation function. For it, the scenariodepicted in Figure 5.25 has been recreated in the lab. The elements involved in this scenarioare: MME, vUGW, PCRF, Online Charging Service (OCS).
In order to verify after the tests, that the results obtained are adequate, these are comparedwith the behaviour expected by the 3GPP standard represented in the diagram of the Figure5.26.
With the aim of having a broader view of this scenario, it has been traced three interfacesinstead of one: S11, Gx and Gy. As it is shown in Figure 5.25, S11 is the interface which links theMME with the vUGW. Through this interface, it will be created the Packet Data Protocol (PDP)context, necessary to do the rest of the charging test. In addition, as it is wanted to do anOnline Charging test, the traffic is also viewed through the Gy and Gx interfaces. Gy connectsthe vUGW with OCS and allows online credit control for service data flow based charging.Moreover, Gx allows communication between the vUGW and PCRF, and it is also responsiblefor the Online Charging, provisioning and removing PCC [1].
Following, the results from the three interfaces are going to be explained: Figure 5.27 hasthe information gathered by S11 and Gy, as well as Figure 5.28 has the data from Gy.
83
Andrea
CHAPTER 5. DEPLOYMENT
Figure 5.26: T01-1101 Online Charging Diagram.
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Before testing the scenario created in the lab, it is necessary to present some conditionsin the NEs involved:
• Check that the LTE/EPC or General Packet Radio Service (GPRS)/UMTS network isfunctioning properly
• Check that the vUGW is functioning properly
• Check that the OCS server is communicating with the vUGW properly
• Check that the signature database has been correctly loaded, and there is no relatedalarm. To view the status of the database:
DSPSIGNATUREDB:; and DSP PARSERDB:;
• Set up a local address pool and bound it to an APN. To see the binding relationship:
LST POOLBINDAPN:;
• Enable the licenses for online charging and Flow-Based Charging (FBC). To view thestatus of the licenses:
LST LICENSESWITCH:;
• Check that the U2000 and vUGW are communicating with each other properly (loggedin to the U2000)
• Create a user tracing task
Once these preset conditions were done, the network was ready to be tested. Figure 5.27has the traces of this first part of the test. The first and the tenth traces are from the interfaceS11. And the rest of the traces are from Gx.
Next, it is explained the meaning of each of these packets:
[1] The vUGW receives from the MME a Create PDP Context Request through GTP. Thistrace has a lot of parameters with data to take into account for the future PDP session.The content of this package is in the Trace 5.2. Next, the content of this trace will beexplained:
[12-15 ] Inside the GPRS Tunneling Protocol, there is information with regards the mes-sage type "Create PDP context request", its sequence number, and its lenght.
[16-18 ] The field IMSI, has information about the MCC and MNC, which indicates thatthe UE is located in Spain, and that Vodafone España is its mobile operator.
[19-21 ] The Acces Point Name is airtelwap.es, which means that UE has configurated thedevice for surfing the Internet.
[22-52 ] QoS has all the parameters which indicates the type of services that are requiredfor this PDP session. For instance, the traffic class, the delivery order, QoS delay,maximun and minimum bit rate, and the guaranteed bit rate uplink/donwlink,among other parameters. All these parameters are sent to receive confirmationwhether they can be used or not.
[53-56 ] One of the last fields refers to the Radio Access Technology (RAT) Type, whichis UMTS Terrestrial Radio Access Network (UTRAN). This radio access networkallows UEs to have access to the UMTS network core using 3G.
[53-56 ] Finally, the last parameter is the User Location Information. As happend for theIMSI, this field also gather information about the location, adding to the MCC andMNC information about the geographic location type, and the cell Location AreaCode (LAC).
[2] Coming back to the general traces of the Online Charging, there is the Credit-Control
Request. This packet is the type of: INITIAL_REQUEST.
The content of this package is in the Trace 5.3:
[13-14 ] In this line, it is indicated the ApplicationId, which is 3GPP Gx with a code of 263for the Session-Id.
[19 ] Inside the Credit-Control Request type, there is the type of message that is, whichhas already been mentioned above: INITIAL_REQUEST.
[21-29 ] Here, in QoS Information there is the confirmation of the parameters of the QoSwere previously asked in frame 1. In it, the most importan information is theAPN-Aggregate-Max-Bitrate Up Link (UL) and Down Link (DL).
[30-40 ] The field Called-Station-Id has data with regard the APN needed, that as it wasshown before, it is airtelwap.es. In addition, there is also information about theOnline Charging, where it is said that this field it is enable with its respective code.Moreover, there is also the code to identify the Access-Network-Charging throughthe interface Gx.
[41-45 ] The RAT-Type is UTRAN since the test is being done in 3G
[46-52 ] The Subscription-Id indicates some data from the subscriptions. For instance,the ID data, the IMSI of the UE, and its location.
R code 5.3: T01-1101 Online Charging - Interface Gx: INITIAL Credit Control Request Trace
1 *---------------------------------------------------------*2 * vUGW 3G - T01 -1101 Real -Time Charging User Services3 *---------------------------------------------------------*4
val =21401982166898349 Subscription -Id-Data: 21401982166898350 IMSI: 21401982166898351 Mobile Country Code (MCC): Spain (214)52 Mobile Network Code (MNC): Vodafone ...
Espana , SAU (01)53 Padding: 00
[3] The next trace is a Credit-Control Answer which comes from the PCRF to the vUGW.This packet is also an INITIAL_REQUEST type, and it is the response of packet 2. Inside,there are allocated information about the charging rules that are going to be appliedduring the PDP session.
The content of this package is in the Trace 5.4:
[17 ] This line refers to the ApplicationId that is being used, which is 3GPP Gx.
[20 ] Result-Code, this is the resolution of the request made by package number 2. Asit is possible to see, this request has been accepted, since the resulting messagewhich was obtained is: DIAMETER_SUCCESS.
In the following lines of this trace, there are the charging rules that have been installedafter accepted the request of package 2. Below is explained one of these charging rules,to better understand what kind of information they may contain:
[27-40 ] Each Charging-Rule-Install has its own code, in this case: 2345. Inside this packet,the most important parameter to keep into account is the Charging-Rule-Name,which in this case is: em_im_wap. This name it is registered in the configurationof the nodes, so when em_im_wap appears, each NE looks in its configuration toknow what rules correspond to this name. After, these rules will be applied to therating of the user.
R code 5.4: T01-1101 Online Charging - Interface Gx: INITIAL Credit Control Answer Trace
1 *---------------------------------------------------------*2 * vUGW 3G - T01 -1101 Real -Time Charging User Services3 *---------------------------------------------------------*4
[10] This trace is a GTP respons with a Create PDP Context Response. This packect indicatesthat the PDP contect has been created.
The content of this package is in the Trace 5.5:
[12-19 ] In the GPRS Tunneling Protocol field, there is the information about the messagetype: Create PDP context response. In addition, in the following lines, it is alsoreflected that the request was accepted: Request accepted
[20 ] The Charging ID indicates what pricing rules should be applied for this UE. Thiscode is searched in the configuration of the nodes and the charge is applied.
[22-48 ] The last line of Quality of Service has the data which has been requested inprevious packets. Here, there are accepted parameters as: QoS delay, Traffic class,Delivery order, Maximum bit rate UL/DL and Transfer delay, among others.
signalling traffic47 Ext Maximum bit rate downlink: 42 Mbps48 Use the value indicated by the Guaranteed bit ...
rate downlink in octet 1349 Bearer Control Mode
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Once the PDP context has been established, the user can begin to browse the Internetand consume data. These data packages are represented in black in Figure 5.27.
As soon as the consumption has begun, UPDATE_REQUEST packets are sent through theGy interface, from the vUGW to the OCS, and vice versa. This kind of traces have the aim ofcontrol consumption and correctly charge the user. Each 20MB consumed by the user, thevUGW request another 20MB to OCS.
Notice that the assigned value of 20MB is not a random value. Prior to its application,several tests were carried out until the most adequate value was found. On one hand, if avalue is set too small, the number of signalling packets between the nodes could saturate thenetwork. On the other hand, if the value is too large, this means that customers cannot bepriced accurately, making them pay for data they have not yet consumed.
This exchange of packages, updating the consumption, occurs until the user reaches hisdata CAP (restriction imposed on the data transfer over the network). At that moment, thespeed of the UE decreases, from the maximum speed contracted to 256 kbps (e.g. Bandwidththrottling).
All this new packet flow is represented in Figure 5.28. The first two packages are the sameas those received through the Gx interface in traces 5.3, and 5.4, so they will not be explainedagain. However, there are two new traces, which are the UPDATE_REQUEST and TERMINA-TION_REQUEST, which will be explained in detail below. Note that these traces are repeatedtwice since one is Credit-Control-Request, and the other is its answer. Considering that theanswers have practically the same information as the requests, it will be explained only theCredit Control Request of both traces UPDATE_REQUEST and TERMINATION_REQUEST.
[3 ] Inside this packet there is information with regards the Credit Control Request -UPDATE_REQUEST. The information of this package is gathered in the Trace 5.6:
[16-17 ] The Command Code and ApplicationId, indicates that the acction in this packetis to control the credit of the user.
[21 ] Here it is possible to distinguish that the trace goes from the GGSN (inside thevUGW) to the OCS.
[28 ] With this line, it is confirmed that this is a trace of the type: Contro Credit-Request, with a value of: UPDATE_REQUEST
[20 ] The Called-Station-Id shows that the APN used is: airtelwap.es
[35- 47 ] Inside the Multiple-Service-Credit-Control there is a field called Rating-Group.As it was explained in previous traces, Vodafone has a service called "VodafonePass". This service allows users to consume all the data they want of some services(e.g. video, music, maps, social...) paying a fixex price. Therefore Vodafone has tobe able to identify which traffic it is being consuming by the user. For it, is usedthe Rating-Group fiel previously mentioned, where there is a code to identify thetype of traffic. In this case, the traffic that the UE is generating is video.
R code 5.6: T01-1101 Online Charging - Interface Gy: UPDATE Credit Control Request Trace
1 *---------------------------------------------------------*2 * vUGW 3G - T01 -1101 Real -Time Charging User Services3 *---------------------------------------------------------*4
Once the PDP session has ended, the vUGW tells to the OCS not to charge more data tothe user. For this purpose the fifth and last packet of this sequence is sent:
[5 ] Credit Control Request - TERMINATION_REQUEST. The content of this package is inthe Trace 5.7:
[29 ] Here, the parameters shown the type of message was sent Control Credit Request:TERMINATION_REQUEST
[30 ] Inside this line, there is information about the Called-Station-Id, which, of courseis again: airtelwap.es
[36 ] The Termination-Cause has the value of DIAMETER_LOGOUT, which means thatthe PDP session has finished and it is time to logout to the session.
[46-63 ] The field Used-Service gathers information with regards the Total Credit con-sumed, which is 33640 MB or 4,2 GB (8368 in hexadecimal). In particular, the datawhich have been consumed is 1,76 GB for UL (3700 in hexadecimal), and 2,25 GBfor DL (4668 in hexadecimal).
The rest of the frame, has information about the parameters that were agreed at thebeginning of the PDP session and now must be eliminated.
R code 5.7: T01-1101 Online Charging - Interface Gy: TERMINATION Credit Control RequestTrace
1 *---------------------------------------------------------*2 * vUGW 3G - T01 -1101 Real -Time Charging User Services3 *---------------------------------------------------------*4
val =357737057164420185 AVP: Vodafone -Rulebase -Id(262) l=15 f=VM- ...
vnd=Vodafone val=wap
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CHAPTER 5. DEPLOYMENT
5G Testing
As it was mentioned before, data core functionalities for 5G are still under the definitionas the 3GPP standard is not ready yet. This is why this test has been conducted using thecommercial standard NSA approved by 3GPP. So, 5G testing was more focused on the RANtesting in order to test the low latency and the high speed that 5G can offer.
Therefore, an infrastructure of a 4G network was needed for traffic control and manage-ment during the test. So the terminals, as well as the base stations, had to establish a dualconnectivity to 4G and 5G networks at the same time. The subbands which were used duringdata transmission are 3,7 GHz and 6 GHz.
The first step was to set up the real scenario for testing. After the setup, several tests weremade until finding the location that was most optimate for the transmission. Once this areawas found, the CPE was placed there, and the first data transmissions were made in 5G withNSA.
The best results obtained in these tests are reflected in Figures 5.29 and 5.30, wherethe results are shown with respect to the throughput, as well as the transmission speed,respectively.
In the case of the Figure 5.29, the behaviors of some protocols, such as Physical Layer(PHY), Media Access Control (MAC), Radio link control (RLC), and Packet Data ConvergenceProtocol (PDCP), are represented. The best values obtained were 480,000 Kbps for acMAC,RLC, and PDCP, and 520,000 Kbps for PHY protocol.
Furthermore, in the speed measurements reflected in Figure 5.30, a latency of just 12 mswas obtained, with a data upload speed of 83,47 Mbps.
The results showed that discharge speeds were reached which multiplied by 8 the standardspeeds of 4G. All the improvements that were made, will be incorporated into the futurecommercial deployment of the new Vodafone 5G technology.
Figure 5.30: Speed measurements in 5G.
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Figure 5.29: Total throughput in 5G measurements.
104
6
CONCLUSION AND FUTURE WORK
This chapter concludes the work done in this master thesis and gives an overview of possiblefuture work.
6.1 CONCLUSIONS
In this master thesis, the current challenges that mobile operators in Spain are facing and itspossible solutions were addressed.
The first goal was to provide enough arguments to explain that the best way to renewVodafone’s data core network was through virtualization. These arguments were supportedby market analysis and validations, which showed that the market situation needed thissolution.
In addition, the importance of having a robust project management to control any unfore-seen events and changes has been reflected. Thanks to PMP methodology the project wasexecuted properly according to scope, time, cost and quality initially defined. Furthermore,thanks to this planning, the reader will have been able to make a broad idea of which are theactivities and times schedules necessary to carry out a project of this type.
The second goal of this master thesis was to provide a technical solution by creating atestbed line with which to test different phases of this project until finding the most optimalsolution. Later this solution would be incorporate to all production lines of Vodafone.
For this purpose, firstly, a discussion on different connectivity design was addressed inorder to solve any network limitation or constraint. For this topic, the number of IPU andAPU VMs were evaluated. Due to the network has limitations, the number of neighbours wasreduced, placing fewer virtual machines. This decreased the throughput inside the network,but even so, the final network implementation has enough capacity to face all the data trafficforecast for the coming years.
It should also be noted that the connectivity option used in the case of the IPU VMswas the one which had a common VLAN which joins routers and the IPU, using OSPF. Inaddition, for the APU VMs the option selected was the one which the service IP addresseswas announced directly by OSPF and do not use any BGP session.
During the installation and configuration stage, the main difficulty was the troubleshoot-ing. Both the installation and the configuration were made following instructions from
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CHAPTER 6. CONCLUSION AND FUTURE WORK
Huawei manuals. However, at the time when there was a failure, there was no manual tofollow, and therefore it has had to do a thorough study to find the root of the problem. Thisstage was probably the one that caused a higher delay in the project execution. In fact, thePDM of the project plan had to be modified several times in order to accommodate the delaysin building a new plan.
Due to the fact that the main objective of this master thesis is to optimize the data corenetwork, one of the most important topics was the SW validation. During this stage, it wasaimed to validate the NFVs correct functioning. After validating it, it was possible to verifythat the network reacted in a more efficient way to scenarios where before there was not sucha good performance.
Concerning the results for the SW validation, 60% of the tests were successful from thebeginning and just for a 25% cases were needed to do troubleshooting. In the case of the 5Gscenario, the results were quite successful, although it was not obtained the maximum bitrateexpected. This was due to the fact that the 3GPP standard is not yet finished so there aremany improvements to face during the following months before reaching the target results.
6.2 FUTURE WORK
It could be interesting to continue working on the virtualization of other NEs, such as PCRF,OCS, databases as HSS, and RANs, among other elements. Doing this, it would be possible tovalidate these components and integrate it with the rest of the network already virtualized.Therefore, having the whole architecture virtualized it would be possible to facilitate thecomplete introduction of the NSA architectures in a close future.
Keeping in mind that the future is 5G networks, might be exciting to focus new researchon developing new NEs, compatible with NSA and SA, to optimize the operation of thesearchitectures. So far, there are some elements that are already created by Huawei, such asCGW and DGW, already shown in this theses. However, there is still a need to develop newelements to compose the complete 5G network in SA.
Another idea that could be interesting to work on, is to go deeper into MEC. Reducinglatency in applications more and more is the future, and MEC is one of the best tools toachieve this goal. Therefore, it could be done research to specify how it is the best way to useMEC in current networks, as well as in NSA and SA.
Finally, Slicing is also another subject with which future research could be carried out.Although this is a concept that is already quite clear, there is still much to investigate andimprove, especially when it comes to entering this concept into the data core networks.
106
A
ABBREVIATIONS
PCRF Policy and Charging Resource Function
PCC Policy and Charging Control
EPC Evolved Packet Core
vEPC Virtual Evolved Packet Core
EPS Evolved Packet System
vEPS Virtual Evolved Packet Core
VNF Virtual Network Functions
VNFI Virtual Network Functions Infrastructure
NFVO NFV Orchestrator
VNFM VNF Manager
HLD High Level Design
LLD Low Level Design
vUGW Virtual Unified Packet Gateway
UGW Unified Packet Gateway
vUSN Virtual Unified Serving Node
VM Virtual Machine
VLAN Virtual Local Area Network
OSPF Open Shortest Path First
107
APPENDIX A. ABBREVIATIONS
ECMP Equal-Cost Multi-Path
IPU I/O Processing Unit
APU Assambly-Service Process Unit
vNIC Virtual Network Interface Controller
HW Hardware
SW Software
IP Internet Protocol
BFD Bidirectional Forwarding Detection
BGP Border Gateway Protocol
APN Access Point Name
GPRS General Packet Radio Service
GTP GPRS Tunneling Protocol
vBOM Virtual Bill of Materials
pBOM Physical Bill of Materials
FOA First of All First Offial Application
MEC Mobile Edge Computing
PDM Precedence Diagram Method
MNO Mobile Network Operator
MVNO Mobile Virtual Network Operator
WO Web Optimization
VO Video Optimizatin
TMF Traffic Management Function
LTE Long Term Evolution
DPI Deep Packet Inspection
108
APPENDIX A. ABBREVIATIONS
vMSP Virtual Multi-Services Platform
MSP Multi-Services Platform
TCP Transmission Control Protocol
MSE Mobile Subscriber Equipement
vMSE Virtual Mobile Subscriber Equipement
PB Petabytes
NFV Network Function Virtualization
NFVI Network Function Virtualization Infrastructure
OTT Over the Top
CAPEX Capital Expenditures
OPEX Operating Expenses
SDN Software Defined Networking
SDNC Software Defined Network Controller
NSA Non Stand-Alone
SA Stand-Alone
GA General Available
ES Early Start
LS Late Start
EF Early Finish
LF Late Finish
PMP Project Management Professional
E2E End-to-End
vOSMU Virtual OSS Self-Maintenance Unit
OSS Operation Support System
109
APPENDIX A. ABBREVIATIONS
BSS Business Support System
MPLS Multiprotocol Label Switching
E/W East-West
RFS Ready for Service
NE Network Element
VPN Virtual Private Network
VRF VPN Routing and Forwarding
CSM Cloud Service Manager
3GPP Third Generation Partnership Project
FTP File Transfer Protocol
CGW Centralized Gateway
DGW Distributed Gateway
CPU Central Processing Unit
vCPU Virtual Central Processing Unit
RAM Random Access Memory
SAN Storage Area Network
MME Mobility Management Entity
SGSN Serving GPRS Support Node
GGSN Gateway GPRS Support Node
P-GW Packet Data Network Gateway
S-GW Serving Gateway
GSM Global System for Mobile comunications
UMTS Universal Mobile Telecommunications System
LTE Long Term Evolution
110
APPENDIX A. ABBREVIATIONS
VIM Virtualized Infrastructure Manager
FCAPS Fault, Configuration, Accounting, Performance, and Security
MANO Management and Orchestration
SFF Service Fulfillment Functions
SAF Service Assurance Functions
TAI Tracking Area Identity
LAI Location Area Identity
MSC Mobile switching center
UE User Equipment
VLR Visitor Location Register
CS Circuit Switching
PS Packet Switching
SMS Short Message Service
IMSI International Mobile Subscriber Identity
MCC Mobile Country Code
MNC Mobile Network Code
CSFB CS-Fallback
HSS Home Subscriber Server
MML Man-Machine Language
EBI Evidence-Based Intervention
PCC Policy and Charging Control
TEID Tunnel Endpoint Identifier
SCTP Stream Control Transmission Protocol
GUTI Global Unique Temporary Identityl
111
APPENDIX A. ABBREVIATIONS
M-TMSI M Temporary Mobile Subscriber Identity
TMSI Temporary Mobile Subscriber Identity
ESM EPS Session Management
NAS Non-Access Stratum
PDN Packet Data Network
SRVCC Single Radio Voice Call Continuity
SIM Subscriber Identity Module
HLR Home Location Register
CPE Customer Premises Equipment
CDR Call Detail Record
OCS Online Charging Service
PDP Packet Data Protocol
FBC Flow-Based Charging
QoS Quality of Service
RAT Radio Access Technology
RAN Radio Acces Network
UTRAN UMTS Terrestrial Radio Access Network
LAC Location Area Code
DL Down Link
UL Up Link
MIMO Multiple Input Multiple Output
CUPS Control Plane - User Plane Separation
IoT Internet of Things
OMU Operating and Management Unit
112
APPENDIX A. ABBREVIATIONS
SDU Session Data Unit
SPU Service Processing Unit
GBU Gb Interface Processing Unit
SIU Signal Interface Process Unit
OAM OWM Operation And Maintainance
SFMU Service Function Management Unit
L3VPN Layer 3 Virtual Private Networks
LUN Logical Unit Number
vCD vCloud Director
EBITDA Earnings Before Interests, Taxes, Depreciations and Amortizations
VAS Value-Added Service
PHY Physical Layer
MAC Media Access Control
RLC Radio link control
PDCP Packet Data Convergence Protocol
113
B
ADDITIONAL INFORMATION
Figure B.1: P3 Overal Results for Voice - Drivetest [3].
115
APPENDIX B. ADDITIONAL INFORMATION
Figure B.2: P3 Overal Results for Data in Cities - Drivetest [3].
116
APPENDIX B. ADDITIONAL INFORMATION
Figure B.3: P3 Overal Results for Data in Towns - Drivetest [3].
117
APPENDIX B. ADDITIONAL INFORMATION
Figure B.4: P3 Overal Results for Data on Roads - Drivetest [3].
118
C
CASES LIST
vUSN 3G
T01 Basic Services
T01-01 IP Bearer Services
T01-0101 Web Services
T02 Mobility Management
T02-01 Attach
T02-0101 GPRS Attach Initiated by a Normal Subscriber Using P-TMSI
T02-02 Detach
T02-0201 Detach Initiated by Switching Off a Normal Subscriber
T02-0202 Detaching a Normal Subscriber from the SGSN
T02-03 Service Request
T02-0301 Service Request of Signaling Type
T02-0302 Service Request of Data Type
T02-04 Paging
T02-0401 Paging Initiated by Downlink Signaling
T02-0402 Paging Initiated by Downlink Data
T02-05 Serving RNC Relocation
T02-0501 Intra SGSN Soft Handover
T03 Security Management
T03-01 Authentication
T03-0101 USIM Authentication
T03-02 Subscriber Data and Signaling Encryption
T03-0201 USIM Subscriber Encryption
T03-0202 SIM Subscriber Encryption
T03-03 Data Integrality
T03-0301 Data Integrality
119
APPENDIX C. CASES LIST
T03-04 Subscriber Identity
T03-0401 Obtaining USIM Subscriber ID
T03-0402 Obtaining SIM Subscriber ID
T03-05 Flexible Authentication Based on Subscriber Group
T03-0501 Flexible Authentication Based on Subscriber Group
T03-06 3G 1/N IMEI Check
T03-0601 1/N IMEI Check During 3G Attach
T04 Subscriber Data Management
T04-01 Inserting Mobile Subscriber Data
T04-0101 Inserting Mobile Subscriber Data
T04-02 Modifying Mobile Subscriber Data
T04-0201 Modifying Mobile Subscriber Data
T04-03 Purge
T04-0301 purge
T05 Session Management
T05-01 PDP Context Activation
T05-0101 PDP Context Activation with a Dynamic Address Initiated by aSubscriber
T05-02 PDP Context Deactivation
T05-0201 PDP Context Deactivation Initiated by a Subscriber
T05-0202 PDP Context Deactivation Initiated by SGSN
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I declare that this thesis does not incorporate without acknowledgment any material previ-ously submitted for a degree or diploma in any university and that to the best of knowledgeit does not contain any materials previously published or written by another person exceptwhere due reference is made in the text.
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