Master thesis deals with architecture of network based on multiprotocol label switching technology (MPLS). Work also describes use of this technology for point to point or multipoint connections based on network or data link layer. The practical part is focused on design of laboratory task which is aimed to configuration of virtual private LAN service (VPLS). This technology emulates multipoint connection based on the data link layer.

Virtual Private LAN Service (VPLS) networks have emerged as a popular solution for providing scalable and efficient Layer 2 connectivity across wide-area networks. However, designing secure and scalable VPLS networks presents significant challenges. The full-mesh tunneling approach in HIP-based VPLS networks results in the N square scalability problem. This thesis addresses the scalability issue in HIP-based Virtual Private LAN Service (VPLS) networks by introducing relay routers. An optimization model based on the Capacitated Facility Location Model is proposed to select the optimal relay routers for a given network topology. The objective of the model is to minimize the cost of setting up and maintaining relay routers while ensuring proper network operation. The proposed solution is evaluated using Software-Defined Networking (SDN) and Mininet-based simulations. The results show that the proposed approach is effective in reducing the scalability issue in HIP-based VPLS networks.

In the introduction of this thesis the reasons for transition from older to a new technology called MultiProtocol Label Switching are mentioned – the modern technology enables simple network extension. The theoretical part contains basic principles of this techno- logy and their practical application for supplying private networks to the customers using provider’s network. In practical part packets are analyzed considering the theory. In addi- tion. All the technologies tested on a real network. Experience gained while working on this thesis are assessed during creating laboratory task for class Architecture of Networks intended for students of Bachelor’s study programme.

Despite two decades of empirical studies focusing on programmers and the problems with programming, usability of textual programming languages is still hard to achieve. Its younger relation, visual programming languages (VPLs) also share the same problem of poor usability. This research explores and investigates the usability issues relating to VPLs in order to suggest a set of design principles that emphasise usability. The approach adopted focuses on issues arising from the interaction and communication between the human (programmers), the computer (user interface), and the program. Being exploratory in nature, this PhD reviews the literature as a starting point for stimulating and developing research questions and hypotheses that experimental studies were conducted to investigate. However, the literature alone cannot provide a fully comprehensive list of possible usability problems in VPLs so that design principles can be confidently recommended. A commercial VPL was, therefore, holistically evaluated and a comprehensive list of usability problems was obtained from the research. Six empirical studies employing both quantitative and qualitative methodology were undertaken as dictated by the nature of the research. Five of these were controlled experiments and one was qualitative-naturalistic. The experiments studied the effect of a programming paradigm and of representation of program flow on novices' performances. The results indicated superiority of control-flow programs in relation to data-flow programs; a control-flow preference among novices; and in addition that directional representation does not affect performance while traversal direction does - due to cognitive demands imposed upon programmers. Results of the qualitative study included a list of 145 usability problems and these were further categorised into ten problem areas. These findings were integrated with other analytical work based upon the review of the literature in a structured fashion to form a checklist and a set of design principles for VPLs that are empirically grounded and evaluated against existing research in the literature. Furthermore, an extended framework for Cognitive Dimensions of Notations is also discussed and proposed as an evaluation method for diagrammatic VPLs on the basis of the qualitative study. The above consists of the major findings and deliverables of this research. Nevertheless, there are several other findings identified on the basis of the substantial amount of data obtained in the series of experiments carried out, which have made a novel contribution to knowledge in the fields of Human-Computer Interaction, Psychology of Programming, and Visual Programming Languages.

<p>This work has been carried out at a company in the region which has about 30000 employeeswith about 400 sites all over the world. The company outsources their network including theLAN refresh and the WAN migration. They needed help with an upgrade of their LAN at theirScandinavian headquarters and to find a new solution for their WAN. The reason why the upgradeof the LAN was needed was that the equipment was too old and did not pass the securityrequirements. They also required a solution to segment their LAN, which consisted of a singlelarge VLAN with 1,300 employees. their WAN solution was made up of tunnels between all officesand the headquarter were used as the central point. They wanted to get away from beingdependent on a central point while redundancy was not always working as it should.The solution to the WAN problem was to use the ISPs backbone based on MPLS. There are two mainsolutions, layer 2 (Ethernet) VPN or layer 3 (IP) VPN. In the case of IP VPN, there are a couple of differentconnectivity options such as a static route, or use a routing protocol (eg OSPF or BGP). The final solutionwas IP VPN with OSPF as routing protocol to the ISP. With regard to the configuration of the OSPF solutionwas that every office became an own OSPF domain, configured with area 0. The report also includesthe implementation of the WAN migration with its problems.The upgrade of the LAN was a lot of planning, documentation and security. The solution for the segmentationwas to create a VLAN per floor. Because of the new software they can have the required securityfeatures.</p>

<p>Jönköping Energi AB (JEAB) is a local energy supplier for the county of Jönköping. JEAB also maintain the local Metropolitan Area Network (MAN). They have recently installed GPON in a portion of their network and have connected it to the MAN via an Extreme switch.</p><p>However JEAB would prefer to use Cisco equipment instead of Extreme since the MAN comprises of Cisco hardware. They require a solution to connect GPON to the MAN with a recently purchased line card (Cisco 7600 ES20) which can be installed in a Cisco 6500 Catalyst switch. There is also a possible solution with an Alcatel-Lucent 7450 ESS-1 switch. The proposed solution is to use Virtual Private LAN Service (VPLS), though the exact implementation required is unknown. Additionally JEAB have asked for research into GPON and VPLS in order to improve their understanding of both techniques. This would be of benefit to them both now and in the future.</p><p>In order to achieve the stated objectives the following questions are raised:</p><p>• How does GPON work?</p><p>• How does VPLS work?</p><p>• How can GPON be connected to the MAN via Cisco Systems 6500 Catalyst switch/7600 Router?</p><p>• How can GPON be connected to the MAN via Alcatel-Lucents 7450 ESS-1?</p><p>The research into GPON and VPLS provides the required background knowledge in order to investigate how GPON can be connected to the MAN. The main body of the work is to analyse the requirements of the company and build a configuration which satisfies them. The desired implementation via Cisco Systems solution was deemed unsuitable due to a feature of DHCP option 82 which did not function as required. The focus then turned to Alcatel-Lucents solution.</p><p>The resulting solution uses a part of VPLS via Alcatel-Lucents 7450 ESS-1. All the key elements are included, including hiding customer VLANs from the ISP and per-service QoS bandwidth management.</p><p>The conclusion is that whilst using Alcatel-Lucents solution means a deviation from the all-Cisco implementation that had been planned; the benefit of including all the desired functionality outweighs the mixing of manufacturers.</p><p>The techniques of GPON and VPLS are extremely versatile and can be used in a variety of networks. Therefore there is scope for further research into how these two techniques can be used together in other types of MAN.</p>

Jönköping Energi AB (JEAB) is a local energy supplier for the county of Jönköping. JEAB also maintain the local Metropolitan Area Network (MAN). They have recently installed GPON in a portion of their network and have connected it to the MAN via an Extreme switch. However JEAB would prefer to use Cisco equipment instead of Extreme since the MAN comprises of Cisco hardware. They require a solution to connect GPON to the MAN with a recently purchased line card (Cisco 7600 ES20) which can be installed in a Cisco 6500 Catalyst switch. There is also a possible solution with an Alcatel-Lucent 7450 ESS-1 switch. The proposed solution is to use Virtual Private LAN Service (VPLS), though the exact implementation required is unknown. Additionally JEAB have asked for research into GPON and VPLS in order to improve their understanding of both techniques. This would be of benefit to them both now and in the future. In order to achieve the stated objectives the following questions are raised: • How does GPON work? • How does VPLS work? • How can GPON be connected to the MAN via Cisco Systems 6500 Catalyst switch/7600 Router? • How can GPON be connected to the MAN via Alcatel-Lucents 7450 ESS-1? The research into GPON and VPLS provides the required background knowledge in order to investigate how GPON can be connected to the MAN. The main body of the work is to analyse the requirements of the company and build a configuration which satisfies them. The desired implementation via Cisco Systems solution was deemed unsuitable due to a feature of DHCP option 82 which did not function as required. The focus then turned to Alcatel-Lucents solution. The resulting solution uses a part of VPLS via Alcatel-Lucents 7450 ESS-1. All the key elements are included, including hiding customer VLANs from the ISP and per-service QoS bandwidth management. The conclusion is that whilst using Alcatel-Lucents solution means a deviation from the all-Cisco implementation that had been planned; the benefit of including all the desired functionality outweighs the mixing of manufacturers. The techniques of GPON and VPLS are extremely versatile and can be used in a variety of networks. Therefore there is scope for further research into how these two techniques can be used together in other types of MAN.

This work has been carried out at a company in the region which has about 30000 employeeswith about 400 sites all over the world. The company outsources their network including theLAN refresh and the WAN migration. They needed help with an upgrade of their LAN at theirScandinavian headquarters and to find a new solution for their WAN. The reason why the upgradeof the LAN was needed was that the equipment was too old and did not pass the securityrequirements. They also required a solution to segment their LAN, which consisted of a singlelarge VLAN with 1,300 employees. their WAN solution was made up of tunnels between all officesand the headquarter were used as the central point. They wanted to get away from beingdependent on a central point while redundancy was not always working as it should.The solution to the WAN problem was to use the ISPs backbone based on MPLS. There are two mainsolutions, layer 2 (Ethernet) VPN or layer 3 (IP) VPN. In the case of IP VPN, there are a couple of differentconnectivity options such as a static route, or use a routing protocol (eg OSPF or BGP). The final solutionwas IP VPN with OSPF as routing protocol to the ISP. With regard to the configuration of the OSPF solutionwas that every office became an own OSPF domain, configured with area 0. The report also includesthe implementation of the WAN migration with its problems.The upgrade of the LAN was a lot of planning, documentation and security. The solution for the segmentationwas to create a VLAN per floor. Because of the new software they can have the required securityfeatures.

Abstract Ethernet based VPLS (Virtual Private LAN Service) is a transparent, protocol independent, multipoint L2VPN (Layer 2 Virtual Private Network) mechanism to interconnect remote customer sites over IP (Internet Protocol) or MPLS (Multiprotocol Label Switching) based provider networks. VPLS networks are now becoming attractive in many Enterprise applications, such as DCI (data center interconnect), voice over IP (VoIP) and videoconferencing services due to their simple, protocol-independent and cost efficient operation. However, these new VPLS applications demand additional requirements, such as elevated security, enhanced scalability, optimum utilization of network resources and further reduction in operational costs. Hence, the motivation of this thesis is to develop secure and scalable VPLS architectures for future communication networks. First, a scalable secure flat-VPLS architecture is proposed based on a Host Identity Protocol (HIP). It contains a session key-based security mechanism and an efficient broadcast mechanism that increase the forwarding and security plane scalability of VPLS networks. Second, a secure hierarchical-VPLS architecture is proposed to achieve control plane scalability. A novel encrypted label-based secure frame forwarding mechanism is designed to transport L2 frames over a hierarchical VPLS network. Third, a novel Distributed Spanning Tree Protocol (DSTP) is designed to maintain a loop free Ethernet network over a VPLS network. With DSTP it is proposed to run a modified STP (Spanning Tree Protocol) instance in each remote segment of the VPLS network. In addition, two Redundancy Identification Mechanisms (RIMs) termed Customer Associated RIMs (CARIM) and Provider Associated RIMs (PARIM) are used to mitigate the impact of invisible loops in the provider network. Lastly, a novel SDN (Software Defined Networking) based VPLS (Soft-VPLS) architecture is designed to overcome tunnel management limitations in legacy secure VPLS architectures. Moreover, three new mechanisms are proposed to improve the performance of legacy tunnel management functions: 1) A dynamic tunnel establishment mechanism, 2) a tunnel resumption mechanism and 3) a fast transmission mechanism. The proposed architecture utilizes a centralized controller to command VPLS tunnel establishment based on real-time network behavior. Hence, the results of the thesis will help for more secure, scalable and efficient system design and development of VPLS networks. It will also help to optimize the utilization of network resources and further reduction in operational costs of future VPLS networks. / Tiivistelmä Ethernet-pohjainen VPLS (Virtual Private LAN Service) on läpinäkyvä, protokollasta riippumaton monipisteverkkomekanismi (Layer 2 Virtual Private Network, L2VPN), jolla yhdistetään asiakkaan etäkohteet IP (Internet Protocol)- tai MPLS (Multiprotocol Label Switching) -yhteyskäytäntöön pohjautuvien palveluntarjoajan verkkojen kautta. VPLS-verkoista on yksinkertaisen protokollasta riippumattoman ja kustannustehokkaan toimintatapansa ansiosta tullut kiinnostavia monien yrityssovellusten kannalta. Tällaisia sovelluksia ovat esimerkiksi DCI (Data Center Interconnect), VoIP (Voice over IP) ja videoneuvottelupalvelut. Uusilta VPLS-sovelluksilta vaaditaan kuitenkin uusia asioita, kuten parempaa tietoturvaa ja skaalautuvuutta, optimaalista verkkoresurssien hyödyntämistä ja käyttökustannusten pienentämistä entisestään. Tämän väitöskirjan tarkoituksena onkin kehittää turvallisia ja skaalautuvia VPLS-arkkitehtuureja tulevaisuuden tietoliikenneverkoille. Ensin väitöskirjassa esitellään skaalautuva ja turvallinen flat-VPLS-arkkitehtuuri, joka perustuu Host Identity Protocol (HIP) -protokollaan. Seuraavaksi käsitellään istuntoavaimiin perustuvaa tietoturvamekanismia ja tehokasta lähetysmekanismia, joka parantaa VPLS-verkkojen edelleenlähetyksen ja tietoturvatason skaalautuvuutta. Tämän jälkeen esitellään turvallinen, hierarkkinen VPLS-arkkitehtuuri, jolla saadaan aikaan ohjaustason skaalautuvuus. Väitöskirjassa kuvataan myös uusi salattu verkkotunnuksiin perustuva tietokehysten edelleenlähetysmekanismi, jolla L2-kehykset siirretään hierarkkisessa VPLS-verkossa. Lisäksi väitöskirjassa ehdotetaan uuden Distributed Spanning Tree Protocol (DSTP) -protokollan käyttämistä vapaan Ethernet-verkkosilmukan ylläpitämiseen VPLS-verkossa. DSTP:n avulla on mahdollista ajaa muokattu STP (Spanning Tree Protocol) -esiintymä jokaisessa VPLS-verkon etäsegmentissä. Väitöskirjassa esitetään myös kaksi Redundancy Identification Mechanism (RIM) -mekanismia, Customer Associated RIM (CARIM) ja Provider Associated RIM (PARIM), joilla pienennetään näkymättömien silmukoiden vaikutusta palveluntarjoajan verkossa. Viimeiseksi ehdotetaan uutta SDN (Software Defined Networking) -pohjaista VPLS-arkkitehtuuria (Soft-VPLS) vanhojen turvallisten VPLS-arkkitehtuurien tunnelinhallintaongelmien poistoon. Näiden lisäksi väitöskirjassa ehdotetaan kolmea uutta mekanismia, joilla voidaan parantaa vanhojen arkkitehtuurien tunnelinhallintatoimintoja: 1) dynaaminen tunnelinluontimekanismi, 2) tunnelin jatkomekanismi ja 3) nopea tiedonsiirtomekanismi. Ehdotetussa arkkitehtuurissa käytetään VPLS-tunnelin luomisen hallintaan keskitettyä ohjainta, joka perustuu reaaliaikaiseen verkon käyttäytymiseen. Tutkimuksen tulokset auttavat suunnittelemaan ja kehittämään turvallisempia, skaalautuvampia ja tehokkaampia VLPS järjestelmiä, sekä auttavat hyödyntämään tehokkaammin verkon resursseja ja madaltamaan verkon operatiivisia kustannuksia.