224 research outputs found

    Measuring TFRC & SCTP Performance Over AODV In MANET

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    This study focuses on TCP-Friendly rate control (TFRC), which is defined by IETF in RFC 5348 as and Stream Control Transmission Protocol (SCTP), which is defined by IETF in RFC 4960 as a new transport protocol. TFRC feature as fairness has attracted real time application and SCTP features also as multi-homing and multi-streaming, has attracted multimedia applications to use it as their transport protocol instead of TCP and UDP. However, the challenge faced by TFRC that is using additive increase to adjust the sending rate during periods with no congestion. This leads to short term congestion that can degrade the quality of voice applications. SCTP faced the challenge in a best-effort network. In this study, a comprehensive performance evaluation between TFRC and SCTP has been carried out. The objectives of this research are to measure the performance of both TFRC and SCTP in MANET in terms of throughput, delay and packet loss that has TFRC and SCTP with UDP traffic some times and some experiments without UDP and the nodes is in mobility positions. All experiments conducted in this research were obtained through network simulation tools using NS-2. It is expected that this study is useful for researchers in improving both TFRC and SCTP

    A Survey of Green Networking Research

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    Reduction of unnecessary energy consumption is becoming a major concern in wired networking, because of the potential economical benefits and of its expected environmental impact. These issues, usually referred to as "green networking", relate to embedding energy-awareness in the design, in the devices and in the protocols of networks. In this work, we first formulate a more precise definition of the "green" attribute. We furthermore identify a few paradigms that are the key enablers of energy-aware networking research. We then overview the current state of the art and provide a taxonomy of the relevant work, with a special focus on wired networking. At a high level, we identify four branches of green networking research that stem from different observations on the root causes of energy waste, namely (i) Adaptive Link Rate, (ii) Interface proxying, (iii) Energy-aware infrastructures and (iv) Energy-aware applications. In this work, we do not only explore specific proposals pertaining to each of the above branches, but also offer a perspective for research.Comment: Index Terms: Green Networking; Wired Networks; Adaptive Link Rate; Interface Proxying; Energy-aware Infrastructures; Energy-aware Applications. 18 pages, 6 figures, 2 table

    A novel multipath-transmission supported software defined wireless network architecture

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    The inflexible management and operation of today\u27s wireless access networks cannot meet the increasingly growing specific requirements, such as high mobility and throughput, service differentiation, and high-level programmability. In this paper, we put forward a novel multipath-transmission supported software-defined wireless network architecture (MP-SDWN), with the aim of achieving seamless handover, throughput enhancement, and flow-level wireless transmission control as well as programmable interfaces. In particular, this research addresses the following issues: 1) for high mobility and throughput, multi-connection virtual access point is proposed to enable multiple transmission paths simultaneously over a set of access points for users and 2) wireless flow transmission rules and programmable interfaces are implemented into mac80211 subsystem to enable service differentiation and flow-level wireless transmission control. Moreover, the efficiency and flexibility of MP-SDWN are demonstrated in the performance evaluations conducted on a 802.11 based-testbed, and the experimental results show that compared to regular WiFi, our proposed MP-SDWN architecture achieves seamless handover and multifold throughput improvement, and supports flow-level wireless transmission control for different applications

    A Communication Architecture for an Advanced Extravehicular Mobile Unit

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    This document describes the communication architecture for the Power, Avionics and Software (PAS) 1.0 subsystem for the Advanced Extravehicular Mobility Unit (AEMU). The following systems are described in detail: Caution Warning and Control System, Informatics, Storage, Video, Audio, Communication, and Monitoring Test and Validation. This document also provides some background as well as the purpose and goals of the PAS subsystem being developed at Glenn Research Center (GRC)

    An SDN-based Overlay Networking Solution for Transparent Multi-homed Vehicular Communications

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    This dissertation consists in the design and development of an Overlay Network for vehicular applications using the SDN paradigm, capable of supporting seamless handover and load balancing between multiple Vehicle-to-Infrastructure (V2I) networks, and also seamless handover of users' terminals between different vehicle zones, such as train carriages. The main contributions of this work are threefold: 1) the overlay SDN-based network architecture designed for vehicular applications such as trains, contemplating the support for multiple V2I operators and multiple gateways per vehicle (e.g., one per carriage); 2) the SDN orchestration component that implements the handover (performed by a User Terminal) from one carriage to another, without Internet connection interruption; and 3) the SDN orchestration component that implements the load-balancing of traffic over multiple V2I links that connect each carriage to the Internet, optimizing the utilization of available network resources and resulting QoS. All the features related to these contributions were implemented in a centralized SDN controller, which has a holistic view of the overlay network, which orchestrates the network hardware on-board of the vehicles. A Proof-of-Concept of the overlay network and the developed components was implemented using Virtual Machines emulating: the network elements of two carriages; the user terminals; a centralized orchestrator; an Internet gateway; and multiple V2I connections representing different operators. Different functional and performance tests were executed, targeting each component, which allowed to successfully validate each contribution

    SIGMA: A mobility architecture for terrestrial and space networks.

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    Internet Protocol (IP) mobility can be handled at different layers of the protocol stack. Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP suffers from a number of drawbacks such as the requirement for infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. As an alternative solution, a few transport layer mobility protocols have been proposed in the context of Transmission Control Protocol (TCP), for example, MSOCKS and TCP connection migration. In this dissertation, a S&barbelow; eamless I&barbelow; P-diversity-based G&barbelow; eneralized M&barbelow; obility Architecture (SIGMA) is described. SIGMA works at the transport layer and utilizes IP diversity to achieve seamless handover, and is designed to solve many of the drawbacks of Mobile IP. It can also cooperate with normal IPv4 or IPv6 infrastructure without the support of Mobile IP. The handover performance, signaling cost, and survivability issues of SIGMA are evaluated and compared with those of Mobile IP. A hierarchical location management scheme for SIGMA is developed to reduce the signaling cost of SIGMA, which is also useful to other transport layer mobility solutions. SIGMA is shown to be also applicable to managing satellite handovers in space. Finally, the interoperability between SIGMA and existing Internet security mechanisms is discussed

    Network layer access control for context-aware IPv6 applications

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    As part of the Lancaster GUIDE II project, we have developed a novel wireless access point protocol designed to support the development of next generation mobile context-aware applications in our local environs. Once deployed, this architecture will allow ordinary citizens secure, accountable and convenient access to a set of tailored applications including location, multimedia and context based services, and the public Internet. Our architecture utilises packet marking and network level packet filtering techniques within a modified Mobile IPv6 protocol stack to perform access control over a range of wireless network technologies. In this paper, we describe the rationale for, and components of, our architecture and contrast our approach with other state-of-the- art systems. The paper also contains details of our current implementation work, including preliminary performance measurements

    A distributed intelligent network based on CORBA and SCTP

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    The telecommunications services marketplace is undergoing radical change due to the rapid convergence and evolution of telecommunications and computing technologies. Traditionally telecommunications service providers’ ability to deliver network services has been through Intelligent Network (IN) platforms. The IN may be characterised as envisioning centralised processing of distributed service requests from a limited number of quasi-proprietary nodes with inflexible connections to the network management system and third party networks. The nodes are inter-linked by the operator’s highly reliable but expensive SS.7 network. To leverage this technology as the core of new multi-media services several key technical challenges must be overcome. These include: integration of the IN with new technologies for service delivery, enhanced integration with network management services, enabling third party service providers and reducing operating costs by using more general-purpose computing and networking equipment. In this thesis we present a general architecture that defines the framework and techniques required to realise an open, flexible, middleware (CORBA)-based distributed intelligent network (DIN). This extensible architecture naturally encapsulates the full range of traditional service network technologies, for example IN (fixed network), GSM-MAP and CAMEL. Fundamental to this architecture are mechanisms for inter-working with the existing IN infrastructure, to enable gradual migration within a domain and inter-working between IN and DIN domains. The DIN architecture compliments current research on third party service provision, service management and integration Internet-based servers. Given the dependence of such a distributed service platform on the transport network that links computational nodes, this thesis also includes a detailed study of the emergent IP-based telecommunications transport protocol of choice, Stream Control Transmission Protocol (SCTP). In order to comply with the rigorous performance constraints of this domain, prototyping, simulation and analytic modelling of the DIN based on SCTP have been carried out. This includes the first detailed analysis of the operation of SCTP congestion controls under a variety of network conditions leading to a number of suggested improvements in the operation of the protocol. Finally we describe a new analytic framework for dimensioning networks with competing multi-homed SCTP flows in a DIN. This framework can be used for any multi-homed SCTP network e.g. one transporting SIP or HTTP
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