1,732 research outputs found
Leveraging Virtualization for Performance Driven Development
This thesis contains the research component of a software engineering study to create a .NET application performance testing lab, and several guided learning activities intended to teach the fundamentals of how to use it. In arriving upon the research which serves as the groundwork for this project, an introduction to the concepts of software performance, the risks associated with performances, and an approach to mitigating this risks called performance driven development is presented. This introduction is expanded by an overview of how performance is affected from application, network, database and presentation aspects. To address problems associated with performance in .NET web applications, a virtual test lab has been created on the software engineering lab server at Regis University\u27s Academic Research Network (ARNe), and this paper documents the architecture of that test lab. In order to demonstrate how it can be used students, developers or others previously unfamiliar with performance testing, a series of presentations has been composed, and this paper represents the research conducted in composing them. This research includes a basic level understanding of Visual Studio Team System 2008\u27s test tools, and virtualization with VMWare
An Innovative RAN Architecture for Emerging Heterogeneous Networks: The Road to the 5G Era
The global demand for mobile-broadband data services has experienced phenomenal growth over the last few years, driven by the rapid proliferation of smart devices such as smartphones and tablets. This growth is expected to continue unabated as mobile data traffic is predicted to grow anywhere from 20 to 50 times over the next 5 years. Exacerbating the problem is that such unprecedented surge in smartphones usage, which is characterized by frequent short on/off connections and mobility, generates heavy signaling traffic load in the network signaling storms . This consumes a disproportion amount of network resources, compromising network throughput and efficiency, and in extreme cases can cause the Third-Generation (3G) or 4G (long-term evolution (LTE) and LTE-Advanced (LTE-A)) cellular networks to crash.
As the conventional approaches of improving the spectral efficiency and/or allocation additional spectrum are fast approaching their theoretical limits, there is a growing consensus that current 3G and 4G (LTE/LTE-A) cellular radio access technologies (RATs) won\u27t be able to meet the anticipated growth in mobile traffic demand. To address these challenges, the wireless industry and standardization bodies have initiated a roadmap for transition from 4G to 5G cellular technology with a key objective to increase capacity by 1000Ã? by 2020 . Even though the technology hasn\u27t been invented yet, the hype around 5G networks has begun to bubble. The emerging consensus is that 5G is not a single technology, but rather a synergistic collection of interworking technical innovations and solutions that collectively address the challenge of traffic growth.
The core emerging ingredients that are widely considered the key enabling technologies to realize the envisioned 5G era, listed in the order of importance, are: 1) Heterogeneous networks (HetNets); 2) flexible backhauling; 3) efficient traffic offload techniques; and 4) Self Organizing Networks (SONs). The anticipated solutions delivered by efficient interworking/ integration of these enabling technologies are not simply about throwing more resources and /or spectrum at the challenge. The envisioned solution, however, requires radically different cellular RAN and mobile core architectures that efficiently and cost-effectively deploy and manage radio resources as well as offload mobile traffic from the overloaded core network.
The main objective of this thesis is to address the key techno-economics challenges facing the transition from current Fourth-Generation (4G) cellular technology to the 5G era in the context of proposing a novel high-risk revolutionary direction to the design and implementation of the envisioned 5G cellular networks. The ultimate goal is to explore the potential and viability of cost-effectively implementing the 1000x capacity challenge while continuing to provide adequate mobile broadband experience to users. Specifically, this work proposes and devises a novel PON-based HetNet mobile backhaul RAN architecture that: 1) holistically addresses the key techno-economics hurdles facing the implementation of the envisioned 5G cellular technology, specifically, the backhauling and signaling challenges; and 2) enables, for the first time to the best of our knowledge, the support of efficient ground-breaking mobile data and signaling offload techniques, which significantly enhance the performance of both the HetNet-based RAN and LTE-A\u27s core network (Evolved Packet Core (EPC) per 3GPP standard), ensure that core network equipment is used more productively, and moderate the evolving 5G\u27s signaling growth and optimize its impact.
To address the backhauling challenge, we propose a cost-effective fiber-based small cell backhaul infrastructure, which leverages existing fibered and powered facilities associated with a PON-based fiber-to-the-Node/Home (FTTN/FTTH)) residential access network. Due to the sharing of existing valuable fiber assets, the proposed PON-based backhaul architecture, in which the small cells are collocated with existing FTTN remote terminals (optical network units (ONUs)), is much more economical than conventional point-to-point (PTP) fiber backhaul designs. A fully distributed ring-based EPON architecture is utilized here as the fiber-based HetNet backhaul. The techno-economics merits of utilizing the proposed PON-based FTTx access HetNet RAN architecture versus that of traditional 4G LTE-A\u27s RAN will be thoroughly examined and quantified. Specifically, we quantify the techno-economics merits of the proposed PON-based HetNet backhaul by comparing its performance versus that of a conventional fiber-based PTP backhaul architecture as a benchmark.
It is shown that the purposely selected ring-based PON architecture along with the supporting distributed control plane enable the proposed PON-based FTTx RAN architecture to support several key salient networking features that collectively significantly enhance the overall performance of both the HetNet-based RAN and 4G LTE-A\u27s core (EPC) compared to that of the typical fiber-based PTP backhaul architecture in terms of handoff capability, signaling overhead, overall network throughput and latency, and QoS support. It will also been shown that the proposed HetNet-based RAN architecture is not only capable of providing the typical macro-cell offloading gain (RAN gain) but also can provide ground-breaking EPC offloading gain.
The simulation results indicate that the overall capacity of the proposed HetNet scales with the number of deployed small cells, thanks to LTE-A\u27s advanced interference management techniques. For example, if there are 10 deployed outdoor small cells for every macrocell in the network, then the overall capacity will be approximately 10-11x capacity gain over a macro-only network. To reach the 1000x capacity goal, numerous small cells including 3G, 4G, and WiFi (femtos, picos, metros, relays, remote radio heads, distributed antenna systems) need to be deployed indoors and outdoors, at all possible venues (residences and enterprises)
Using decoys to block SPIT in the IMS
Includes bibliographical references (leaves 106-111)In recent years, studies have shown that 80-85% of e-mails sent were spam. Another form of spam that has just surfaced is VoIP (Voice over Internet Telephony) spam. Currently, VoIP has seen an increasing numbers of users due to the cheap rates. With the introduction of the IMS (IP Multimedia Subsystem), the number of VoIP users are expected to increase dramatically. This calls for a cause of concern, as the tools and methods that have been used for blocking email spam may not be suitable for real-time voice calls. In addition, VoIP phones will have URI type addresses, so the same methods that were used to generate automated e-mail spam messages can be employed for unsolicited voice calls. Spammers will always be present to take advantage of and adapt to trends in communication technology. Therefore, it is important that IMS have structures in place to alleviate the problems of spam. Recent solutions proposed to block SPIT (Spam over Internet Telephony) have the following shortcomings: restricting the users to trusted senders, causing delays in voice call set-up, reducing the efficiency of the system by increasing burden on proxies which have to do some form of bayesian or statistical filtering, and requiring dramatic changes in the protocols being used. The proposed decoying system for the IMS fits well with the existing protocol structure, and customers are oblivious of its operation
A Comparison Study on the Performance of Different Applications using MANET Routing Protocols under Various Circumstances
Mobile adhoc network is a collection of mobile devices that communicate amongst each other using message passing to collaborate in a wireless medium, without any centralized management; each device acts as a router, sends and receive packets. Nodes can move freely and can set itself in any adhoc network. Adhoc networks are widely use in the absence of the wired network infrastructure. Quality of service of routing in ad hoc networks is an important and complicated issue with a changing topology. In this work we carried out a comparison study in a simulation scenarios on the performance of different routing protocols i.e., proactive and reactive, with different standard applications such as FTP, HTTP and database under various circumstances by means of network size, load, and speed of nodes. As a conclusion of this study, results show when measuring performance of delay and throughput of FTP, HTTP and Database traffic, delay and throughput metrics, using AODV, DSR, OLSR routing protocols, under 10, 50 and 100 nodes with spee of 10, 30 m/s. When using DSR routing protocol it showed the worst results under various network size and speed between other protocols, while when using AODV routing protocol it performed in a better way in which it showed a good performance in small and medium network size. OLSR routing protocol performed the best to be used in all network size especially in large network size.مانيت هي عبار ة عن مجموعة من االجهز ة تحتوي عمى أجهز ة السمكية، تتعاون مع بعضها البعض الرسال، استقبال و نقل المعمومات من خالل وسط السمكي، هوائي، من دون اي تحكم مركزي، كل جهاز يمكن اعتبار ة كجهاز راوتر يعتمد عمى نفسة بحيث يستقبل و يرسل المعمومات و هذة المجموعة تسمى بالمانيت. أي جهاز بهذة المجموعة يمكنة التحرك بحرية و يمكنة االنضمام الي مجموعة مانيت بالوقت الذي يريدة و بالمكان الذي يريدة. تستخدم المانيت باألمكان الذي اليوجد فيها بنية تحتية ثابتة، باألمكان التي يحصل فيها كوارث طبيعية و األمكان الذي يصعب فيها وجود اتصال بالوقت الذي يكون هو ضروري لوجود شبكة بين الجهز ة. تستخدم هذة األجهزة بروتوكالت لنقل المعمومات مثل DSR AODV و غيرها من البروتوكالت، حيث ان المانيت شبكة سريعة التغيير فان جودة هذة البروتوكالت هو أمر مهم. في هذة الرسالة قمنا بدراسة التطبيقات،database HTTP FTP ، لشبكة المانيت باستخدام البروتوكالت AODV ، DSR ، OLSR كال عمى حدى، تحت متغيرات و ظروف معينة لمعرفة اي بروتوكل هو االنسب الستخدامة مع اي تطبيق تحت هذة الظروف. و كنتيجة لهذة الدراسة، عند قياس أداء FTP ،Database، HTTP مقاييس اإلنتاجية، وذلك
باستخدام AODV ،DSR ،OLSR بروتوكوالت التوجية ، تحت 01،01 و 011 عقدة وتصل سرعتها من 01 ، 01 م / ث.تبين انة عند استخدام بروتوكول توجية DSR أظهرت أسوأ نتائج في جميع اإلطار ت من حيت حجم الشبكة والسرعة بين البروتوكوالت األخرى، بينما عند استخدام بروتوكول التوجية AODV تنفذ ذلك بطريقة أفضل بحيت أظهرت أداء جيدا في حجم الشبكة الصغير والمتوسطة. اما بنسبة لبروتوكول التوجية OLSR اظهر أداء أفضل الستخدامها في جميع احجام الشبكة وخصوصا في حجم شبكة الواسع
Reducing Internet Latency : A Survey of Techniques and their Merit
Bob Briscoe, Anna Brunstrom, Andreas Petlund, David Hayes, David Ros, Ing-Jyh Tsang, Stein Gjessing, Gorry Fairhurst, Carsten Griwodz, Michael WelzlPeer reviewedPreprin
Development of a multi-mode self-adaptive algorithm to create an efficient wireless network on a university campus
The expanding use of ubiquitous computing has created a significant demand on existing network infrastructures. The demands of voice, video, and data on the same medium require a quality of service (QoS) at a level acceptable to users. Many network providers simply scale their networks to increase bandwidth and hardware to deal with the increasing demands. However, a network may still reach its design limits with peak traffic or malicious overuse of resources. In addition, with technology changing at a rapid pace, it is difficult to provide sufficient staffing to monitor and adjust the network settings to avoid issues during periods of network saturation. One of the common method to address these issues involves implementing a traffic shaper. A traffic shaper is a computer network management technique by which data sent across the network is delayed or routed in a way to accommodate a specific level of traffic to reach a desired QoS. There are many existing traffic shaping algorithms, each performing well under specific circumstances improving some QoS measures. The algorithms make use of queuing schemes to sort and send traffic based on the parameters provided to the system. To determine the need for this research, a survey was administered which revealed dissatisfaction with QoS of the wireless network. The purpose of this study focused on the development of a traffic shaping algorithm that would improve the QoS on a local area network on a university campus. The goal of the research was to create a new architecture that would allow a router to dynamically shift between different queuing mechanisms to improve network delay and packet loss without negatively impacting data throughput. The Multi-Mode Self-Adaptive (MMSA) algorithm was proposed to define a mechanism for this architecture. The MMSA was implemented within the code of a Cisco® router in the OPNET Modeler software and tested in a simulated university network environment. The results of the simulation revealed an improvement in end to end delay and packet loss rate with an insignificant change in average transmit rate between the router and the external server. The results of this research can be used as a basis for future research to create a new QoS framework. The new framework could be implemented in a router to allow configurations tailored to the network requirements of a service provider
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