446 research outputs found
Design and implementation of a differentiated service based qos model for real-time interactive traffic on constrained bandwidth ip networks
In this thesis work, a QoS model for real-time interactive traffic on a real
network with constrained bandwidth and real-time traffic has been proposed. The
model supports tight guarantees of QoS to real-time interactive traffic without
over provisioning of bandwidth. A dynamic scheduling model which is adaptive to
input data rate of traffic has been proposed. In this model, A Differentiated
Service (DiffServ) based approach is proposed for QoS provisioning. The packets
are classified and distributed among finite number of queues with limited
buffer based on different priorities and total available bandwidth. The model
proposes a mechanism to derive the weighted service rates and queue length
distribution so as to meet the requirement of low packet loss and delay for
real time interactive traffic in the QoS engineered network. An adaptive
queuing strategy is proposed so that minimum bandwidth in used for real time
traffic. This ensures maximizing availability to best effort traffic. The model
assumes constrained bandwidth without having to over provision the network
resources and thus keeping the cost low. A modified version suitable for
testing on a real network is also presented. Experimental verification of these
in a test bed network in a laboratory as well as on a real network has been
carried out. The results of the QoS provisioning model for different sources of
real-time traffic such as video conferencing equipment, robotic surveillance
camera has also been shown. The thesis also introduces a real-time Variable Bit
Rate (VBR) traffic tuning parameter for controlling the service of VBR traffic
to give better and fair performance to rest of the traffic
The system architecture of the Pocket Companion
In the Moby Dick project we design the architecture of a so-called Pocket Companion. It is a small personal portable computer with wireless communication facilities for every day use. The typical use of the Pocket Companion induces a number of requirements concerning security, performance, energy consumption, communication and size. We have shown that these requirements are interrelated and can only be met optimal with one single architecture. The Pocket Companion architecture consists of a central switch with a security module surrounded by several modules. The Pocket Companion is a personal machine. Communication, and particularly wireless communication, is essential for the system to support electronic transactions. Such a system requires a good security infrastructure not only for safeguarding personal data, but also to allow safe (financial) transactions. The integration of a security module in the Pocket Companion architecture provides the basis for a secure environment.\ud
Because battery life is limited and battery weight is an important factor for the size and the weight of the Pocket Companion, energy consumption plays a crucial role in the architecture. An important theme of the architecture is: enough performance for minimal energy consumption
Analysis, Modification, and Implementation (AMI) of Scheduling Algorithm for the IEEE 802.116e (Mobile WiMAX)
Mobile WiMAX (Worldwide Interoperability for Microwave Access) is being
touted as the most promising and potential broadband wireless technology. And
the popularity rate has been surging to newer heights as the knowledge-backed
service era unfolds steadily. Especially Mobile WiMAX is being projected as a
real and strategic boon for developing counties such as India due to its
wireless coverage acreage is phenomenally high. Mobile WiMAX has spurred
tremendous interest from operators seeking to deploy high-performance yet
cost-effective broadband wireless networks. The IEEE 802.16e standard based
Mobile WiMAX system will be investigated for the purpose of Quality of Service
provisioning. As a technical challenge, radio resource management will be
primarily considered and main is the costly spectrum and the increasingly more
demanding applications with ever growing number of subscribers. It is necessary
to provide Quality of Service (QoS) guaranteed with different characteristics.
As a possible solution the scheduling algorithms will be taken into main
consideration and the present well known algorithms will be described. In this
paper, we have highlighted the following critical issues for Mobile WiMAX
technologies. This paper specifically discussed about the below mentioned in
detail. - QoS Requirements For IEEE 802.16 Service Classes, Achieving efficient
radio resource management. - Deficit Round Robin (DRR) Scheduling algorithm. -
Modified Deficit Round Robin (MDRR) scheduling algorithm's attributes,
properties and architecture. System Model And Scenarios Using OPNET Modeler
Software. - Simulation Limitations And Constraints.Comment: Pages IEEE format, International Journal of Computer Science and
Information Security, IJCSIS, Vol. 7 No. 2, February 2010, USA. ISSN 1947
5500, http://sites.google.com/site/ijcsis
Implementation and Evaluation of Measurement-Based Admission Control Schemes Within a Converged Networks QoS Management Framework
Policy-based network management (PBNM) paradigms provide an effective tool
for end-to-end resource management in converged next generation networks by
enabling unified, adaptive and scalable solutions that integrate and
co-ordinate diverse resource management mechanisms associated with
heterogeneous access technologies. In our project, a PBNM framework for
end-to-end QoS management in converged networks is being developed. The
framework consists of distributed functional entities managed within a
policy-based infrastructure to provide QoS and resource management in converged
networks. Within any QoS control framework, an effective admission control
scheme is essential for maintaining the QoS of flows present in the network.
Measurement based admission control (MBAC) and parameter based admission
control (PBAC) are two commonly used approaches. This paper presents the
implementation and analysis of various measurement-based admission control
schemes developed within a Java-based prototype of our policy-based framework.
The evaluation is made with real traffic flows on a Linux-based experimental
testbed where the current prototype is deployed. Our results show that unlike
with classic MBAC or PBAC only schemes, a hybrid approach that combines both
methods can simultaneously result in improved admission control and network
utilization efficiency.Comment: 16 pages, 8 figures, Journal pape
Towards automated composition of convergent services: a survey
A convergent service is defined as a service that exploits the convergence of communication networks and at the same time takes advantage of features of the Web. Nowadays, building up a convergent service is not trivial, because although there are significant approaches that aim to automate the service composition at different levels in the Web and Telecom domains, selecting the most appropriate approach for specific case studies is complex due to the big amount of involved information and the lack of technical considerations. Thus, in this paper, we identify the relevant phases for convergent service composition and explore the existing approaches and their associated technologies for automating each phase. For each technology, the maturity and results are analysed, as well as the elements that must be considered prior to their application in real scenarios. Furthermore, we provide research directions related to the convergent service composition phases
A Survey on the Contributions of Software-Defined Networking to Traffic Engineering
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-
Smoothing and Modeling of Video Transmission Rates over a QoS Network with Limited Bandwidth Connections
Transmission of video over a limited bandwidth network is challenging due to
the natural variability of video, and link characteristics. Video smoothing
techniques can be used to facilitate more effective transmission and to
preserve better quality. In this paper we develop a semi-optimal video
smoothing approach to manage the transmission of MPEG-4 and H.264 video while
mapping it to be more suitable for a QoS based network. The proposed technique
utilizes a smoothing buffer with pre-defined thresholds to smooth the
transmission rates while assuming minimal information about the video to be
transmitted. The results obtained showed a significant improvements in
transmission rate variability while guaranteeing no buffer overflows or
underflows. In addition, a queuing model is developed for the used smoothing
algorithm for H.264 video streams with optimized encoding and packetization,
utilizing the available H.264 macroblock ordering option
Context-aware VoIP congestion control service
IP networks can have difficulty coping with delay-sensitive VoIP traffics during emergency situations caused by fires and related disasters. During emergencies there is a huge increase in voice and video traffic, causing a huge strain on the network. The strain on the network is as a result of both essential and non-essential traffic. In such crisis situations, calls originating from or destined for rescue personnel, such as doctors and police, are considered essential. Any other calls from eyewitnesses and the public are considered non-essential, since they degrade the quality of service for the emergency response teams by consuming the scarce network resources. Providing the rescue team with the quality of service that they require necessitates network access restriction for non-essential traffic. In this paper, the authors present a voice and video service that uses Context-Awareness and Semantic Web technologies to restrict network access to privileged users during crisis situations. The service monitors the network for crisis conditions, enables the network to respond appropriately when a crisis occurs, detects the end of the crisis and reverts to its default state
The EuQoS system: A solution for QoS routing in heterogeneous networks
EuQoS is the acronym for âend-to-end quality of service support over heterogeneous networks,âwhich is a European research project aimed at building an entire QoS framework,addressing all the relevant network layers, protocols, and technologies. This framework, which includes the most common access networks (xDSL, UMTS, WiFi, and LAN) is being prototyped and tested in a multidomain scenario throughout Europe, composing what we call the EuQoS system. In this article we present the novel QoS routing mechanisms that are being
developed and evaluated in the framework of this project. The preliminary performance results validate the design choices of the EuQoS system, and confirm the potential impact this project is likely to have in the near future.Postprint (published version
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