154 research outputs found

    Overlay networks for smart grids

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    Performance Evaluation of MPLS in a Virtualized Service Provider Core (with/without Class of Service)

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    The last decade has witnessed a major change in the types of traffic scaling the Internet. With the development of real-time applications several challenges were faced within traditional IP networks. Some of these challenges are delay, increased costs faced by the service provider and customer, limited scalability, separate infrastructure costs and high administrative overheads to manage large networks etc. To combat these challenges, researchers have steered towards finding alternate solutions. Over the recent years, we have seen an introduction of a number of virtualized platforms and solutions being offered in the networking industry. Virtual load balancers, virtual firewalls, virtual routers, virtual intrusion detection and preventions systems are just a few examples within the Network Function Virtualization world! Service Providers are trying to find solutions where they could reduce operational expenses while at the same time meet the growing bandwidth demands of their customers. The main aim of this thesis is to evaluate the performance of voice, data and video traffic in a virtualized service provider core. Observations are made on how these traffic types perform on congested vs uncongested links and how Quality of Service treats traffic in a virtualized Service Provider Core using Round Trip Time as a performance metric. This thesis also tries to find if resiliency features such as Fast Reroute provide an additional advantage in failover scenarios within virtualized service provider cores. Juniper Networks vSRX are used to replicate virtual routers in a virtualized service provider core. Twenty-Four tests are carried out to gain a better understanding of how real-time applications and resiliency methods perform in virtualized networks. It is observed that a trade-off exists when introducing QoS on congested primary and secondary label switched paths. What can be observed thru the graphs is having Quality of Service enabled drops more packets however gives us the advantage of lower Round Trip Time for in-profile traffic. On the hand, having Quality of Service disabled, permits more traffic but leads to bandwidth contention between the three traffic classes leading to higher Round-Trip Times. The true benefit of QoS is seen in traffic congestion scenarios. The test bed built in this thesis, shows us that Fast Reroute does not add a significant benefit to aid in the reduction of packet loss during failover scenarios between primary and secondary paths. However, in certain scenarios fast reroute does seem to reduce packet loss specifically for data traffic

    A Continuous Overlay Path Probing Algorithm For Overlay Networks

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    Bandwidth is a key factor in network technologies and it has been of major importance throughout the history of packet networks. In fact, bandwidth estimation is very beneficial to optimize the performance of end-to-end transport in several overlay applications such as Content Distribution Networks (CDNs), Peer-to-Peer (P2P) file sharing, and dynamic overlay routing. The end-to-end available bandwidth determines the extra bandwidth that can be provided to overlay traffic. Knowledge about the available bandwidth of an overlay path enables dynamic rate adoption and better bandwidth utilization by content distribution schemes in overlay networks. However, the important issue is how to measure the available bandwidth on an end-to-end overlay path without prior knowledge about the physical network. Over the last two decades, researchers have been trying to create algorithms to measure end-to-end available bandwidth and other bandwidth-related metrics accurately, quickly, and without affecting the traffic of the path. Active measurement techniques performed by overlay nodes can provide bandwidth estimations of an end-to-end overlay path. This thesis describes a new algorithm called “COPPA,” which is an in-band path probing algorithm for measuring the end-to-end available bandwidth of an overlay path accurately and continuously. The aim is to provide up-to-date bandwidth information for enhanced content distribution processes in overlay networks. The primary idea is to perform active measurements using the applications’ packets instead of using extra probe packets. Such an in-band probing algorithm reduces measurement overhead on the selected overlay path. Several experiments were carried out using the OMNeT++ simulation framework. The designed algorithm was evaluated using experimental data. The obtained results show that the continuous in-band overlay path probing algorithm (COPPA) provides up-to-date bandwidth information with reduced overhead and minimal impact on the traffic of the path

    A Survey on the Contributions of Software-Defined Networking to Traffic Engineering

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    Since the appearance of OpenFlow back in 2008, software-defined networking (SDN) has gained momentum. Although there are some discrepancies between the standards developing organizations working with SDN about what SDN is and how it is defined, they all outline traffic engineering (TE) as a key application. One of the most common objectives of TE is the congestion minimization, where techniques such as traffic splitting among multiple paths or advanced reservation systems are used. In such a scenario, this manuscript surveys the role of a comprehensive list of SDN protocols in TE solutions, in order to assess how these protocols can benefit TE. The SDN protocols have been categorized using the SDN architecture proposed by the open networking foundation, which differentiates among data-controller plane interfaces, application-controller plane interfaces, and management interfaces, in order to state how the interface type in which they operate influences TE. In addition, the impact of the SDN protocols on TE has been evaluated by comparing them with the path computation element (PCE)-based architecture. The PCE-based architecture has been selected to measure the impact of SDN on TE because it is the most novel TE architecture until the date, and because it already defines a set of metrics to measure the performance of TE solutions. We conclude that using the three types of interfaces simultaneously will result in more powerful and enhanced TE solutions, since they benefit TE in complementary ways.European Commission through the Horizon 2020 Research and Innovation Programme (GN4) under Grant 691567 Spanish Ministry of Economy and Competitiveness under the Secure Deployment of Services Over SDN and NFV-based Networks Project S&NSEC under Grant TEC2013-47960-C4-3-

    Internet Interconnection Ecosystem in Finland

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    For both fixed and mobile network operators, interconnection constitutes an indisputably key element to provide end users with a variety of services. Internet interconnection is particularly an intriguing subject due to the importance of the Internet in our everyday lives and our genuine curiosity to grasp its underlying structure. This thesis aims to provide a holistic approach to study the Internet interconnections in a nation-centric stance. To accomplish the objective, initially the method that breaks down the key features of the interconnection analysis is introduced. The nation-centric analysis is conducted for Finland by jointly utilizing the Internet registry data and collected Internet routing data. Covering the last decade of the Finnish Internet, the longitudinal analysis yields significant findings for the Internet address usage statistics and the level of multi-homed networks, along with the classification and inference of relationships between stakeholders in the interconnection ecosystem. The implications that the emerging interconnection models pose for the future global service delivery among both fixed and mobile networks are expounded from the perspective of the existing domestic interconnection practices. The longitudinal interconnectivity study allows us to comprehend both technical and business interfaces between market players by revealing a complete list of customer-provider relationships. Within a national milieu, the assessment of the current Internet market dynamics and future implications of emerging models can be considered in more rationally anticipated manner. Hence, authorities who desire to design new pricing schemes and policies for future networking interconnections can be guided more thoroughly

    Multi-Tier Diversified Service Architecture for Internet 3.0: The Next Generation Internet

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    The next generation Internet needs to support multiple diverse application contexts. In this paper, we present Internet 3.0, a diversified, multi-tier architecture for the next generation Internet. Unlike the current Internet, Internet 3.0 defines a new set of primitives that allows diverse applications to compose and optimize their specific contexts over resources belonging to multiple ownerships. The key design philosophy is to enable diversity through explicit representation, negotiation and enforcement of policies at the granularity of network infrastructure, compute resources, data and users. The basis of the Internet 3.0 architecture is a generalized three-tier object model. The bottom tier consists of a high-speed network infrastructure. The second tier consists of compute resources or hosts. The third tier consists of data and users. The “tiered” organization of the entities in the object model depicts the natural dependency relationship between these entities in a communication context. All communication contexts, including the current Internet, may be represented as special cases within this generalized three-tier object model. The key contribution of this paper is a formal architectural representation of the Internet 3.0 architecture over the key primitive of the “Object Abstraction” and a detailed discussion of the various design aspects of the architecture, including the design of the “Context Router-” the key architectural element that powers an evolutionary deployment plan for the clean slate design ideas of Internet 3.0

    Collaborative communications among multiple points.

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    Zhang Xinyan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves [78]-[85]).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Multiple Point Communication --- p.1Chapter 1.2 --- Major Contributions --- p.2Chapter 1.3 --- Thesis Organization --- p.4Chapter 2 --- Related Work --- p.5Chapter 2.1 --- Peer-to-Peer Networks --- p.5Chapter 2.2 --- Application Layer Multicast --- p.11Chapter 2.3 --- Internet Traffic Engineering --- p.19Chapter 3 --- MultiServ: Application Layer Multiple Path Routing --- p.23Chapter 3.1 --- Motivation --- p.24Chapter 3.2 --- MultiServ Overlay Construction --- p.28Chapter 3.3 --- MultiServ Routing --- p.33Chapter 3.3.1 --- The importance of routing strategy --- p.33Chapter 3.3.2 --- Solutions for IP network --- p.35Chapter 3.3.3 --- MultiServ routing --- p.37Chapter 3.3.4 --- MultiServ routing with bounded complexity --- p.39Chapter 3.3.5 --- Routing implementation --- p.41Chapter 3.4 --- Performance Evaluation --- p.45Chapter 3.4.1 --- End-to-end streaming --- p.45Chapter 3.4.2 --- Application-layer multicast --- p.50Chapter 3.4.3 --- Experiments in real network --- p.54Chapter 3.5 --- Summary and Future Work --- p.57Chapter 4 --- DDS: Distributed Dynamic Streaming --- p.59Chapter 4.1 --- Motivation --- p.59Chapter 4.2 --- Distributed Dynamic Streaming --- p.61Chapter 4.2.1 --- DDS overlay construction --- p.62Chapter 4.2.2 --- DDS streaming --- p.64Chapter 4.3 --- Performance Analysis in Dynamic User Environment --- p.66Chapter 4.3.1 --- Basic definition and user model --- p.67Chapter 4.3.2 --- Data outage in tree topology --- p.68Chapter 4.3.3 --- Data outage in DDS --- p.70Chapter 4.4 --- Performance Evaluation --- p.73Chapter 4.4.1 --- Simulation setup --- p.73Chapter 4.4.2 --- Simulation results --- p.74Chapter 4.5 --- Summary and Future Work --- p.75Chapter 5 --- Concluding Remarks --- p.76Bibliography --- p.7
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