8,050 research outputs found

    Scalable QoS routing in MPLS networks using mobile code

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    In a continually evolving Internet, tools such as Q u a lity o f Service ro u tin g must be used in order to accommodate user demands. However, deploying and developing QoS routing in the legacy Internet is difficult. Multiprotocol Label Switching (MPLS) facilitates the deployment of QoS routing, due to its separation of functions between the control and forwarding plane. Developing QoS routing raises scalability issues within very large networks. I propose overcoming these issues by using topology aggregation and distributed routing based on modem techniques such as active networks and mobile agents. However, topology aggregation introduces inaccuracy, which has a negative impact on QoS routing performance. To avoid such problems I propose a hierarchical routing protocol, called Macro-routing, which by using distributed route computation is able to process more detailed information and thus to use the most accurate aggregation technique, i.e. Full-Mesh. Therefore, the protocol is more likely to find the best path between source and destination, and can also find more than one available path. QoS routing, which is used for finding feasible paths that simultaneously satisfy multiple constraints, is also called multiple-constrained routing and is an NP-complete problem. The difficulty of solving such problems increases in a hierarchical context, where aggregation techniques influence the path computation process. I propose a new aggregation technique which allows the selection of multiple paths that satisfy multiple QoS constraints. This reduces the probability of a false negative, i.e., of the routing algorithm incorrectly reporting that no path satisfying the constraints exists. This aggregation technique is called extended full-mesh (EFM) and is intended for use with the Macro-routing protocol. Deploying these protocols in the Internet will allow multi-constrained routing to be practically implemented on large networks

    A QoS-Driven ISP Selection Mechanism for IPv6 Multi-homed Sites

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    A global solution for the provision of QoS in IPng sites must include ISP selection based on per-application requirements. In this article we present a new site-local architecture for QoS-driven ISP selection in multi-homed domains, performed in a per application basis. This architecture proposes the novel use of existent network services, a new type of routing header, and the modification of address selection mechanisms to take into account QoS requirements. This proposal is an evolution of current technology, and therefore precludes the addition of new protocols, enabling fast deployment. The sitelocal scope of the proposed solution results in ISP transparency and thus in ISP independency.This research was supported by the LONG (Laboratories Over the Next Generation Networks) project IST-1999-20393.Publicad

    Macro-routing: a new hierarchical routing protocol

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    In a continually evolving Internet, tools such as quality of service routing must be used in order to accommodate user demands. QoS routing raises scalability issues within very large networks, which can he avoided by using hierarchical routing strategies. However, such strategies can lead to inaccurate path selection due to the aggregation process. To avoid such problems, we propose a hierarchical routing protocol, called macro-routing, which can distribute the route computation more efficiently throughout the network using mobile agents. It processes more detailed information than conventional hierarchical routing protocols, so is more likely to find the best path between source and destination. Also, by using mobile agents, more than one available path can be found. This provides a fast recovery mechanism, where no protocol restart is needed in a failure situation

    Publish/subscribe protocol in wireless sensor networks: improved reliability and timeliness

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    The rapidly-evolving demand of applications using wireless sensor networks in several areas such as building and industrial automation or smart cities, among other, makes it necessary to determine and provide QoS support mechanisms which can satisfy the requirements of applications. In this paper we propose a mechanism that establishes different QoS levels, based on Publish/Subscribe model for wireless networks to meet application requirements, to provide reliable delivery of packet and timeliness. The first level delivers packets in a best effort way. The second one intends to provide reliable packet delivery with a novel approach for Retransmission Timeout (RTO) calculation, which adjusts the RTO depending on the subscriber Packet Delivery Ratio (PDR). The third one provides the same reliable packet delivery as the second one, but in addition, it provides data aggregation trying to be efficient in terms of energy consumption and the use of network bandwidth. The last one provides timeliness in the packet delivery. We evaluate each QoS Level with several performance metrics such as PDR, Message Delivery Ratio, Duplicated and Retransmitted Packet Ratio and Packet Timeliness Ratio to demonstrate that our proposal provides significant improvements based on the increase of the PDR obtained.Peer ReviewedPostprint (author's final draft

    Overlay networks for smart grids

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    Multi-layer virtual transport network management

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    Nowadays there is an increasing need for a general paradigm which can simplify network management and further enable network innovations. Software Defined Networking (SDN) is an efficient way to make the network programmable and reduce management complexity, however it is plagued with limitations inherited from the legacy Internet (TCP/IP) architecture. In this paper, in response to limitations of current Software Defined Networking (SDN) management solutions, we propose a recursive approach to enterprise network management, where network management is done through managing various Virtual Transport Networks (VTNs) over different scopes (i.e., regions of operation). Different from the traditional virtual network model which mainly focuses on routing/tunneling, our VTN provides communication service with explicit Quality-of-Service (QoS) support for applications via transport flows, and it involves all mechanisms (e.g., addressing, routing, error and flow control, resource allocation) needed to support such transport flows. Based on this approach, we design and implement a management architecture, which recurses the same VTN-based management mechanism for enterprise network management. Our experimental results show that our management architecture achieves better performance.National Science Foundation awards: CNS-0963974 and CNS-1346688

    EC-CENTRIC: An Energy- and Context-Centric Perspective on IoT Systems and Protocol Design

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    The radio transceiver of an IoT device is often where most of the energy is consumed. For this reason, most research so far has focused on low power circuit and energy efficient physical layer designs, with the goal of reducing the average energy per information bit required for communication. While these efforts are valuable per se, their actual effectiveness can be partially neutralized by ill-designed network, processing and resource management solutions, which can become a primary factor of performance degradation, in terms of throughput, responsiveness and energy efficiency. The objective of this paper is to describe an energy-centric and context-aware optimization framework that accounts for the energy impact of the fundamental functionalities of an IoT system and that proceeds along three main technical thrusts: 1) balancing signal-dependent processing techniques (compression and feature extraction) and communication tasks; 2) jointly designing channel access and routing protocols to maximize the network lifetime; 3) providing self-adaptability to different operating conditions through the adoption of suitable learning architectures and of flexible/reconfigurable algorithms and protocols. After discussing this framework, we present some preliminary results that validate the effectiveness of our proposed line of action, and show how the use of adaptive signal processing and channel access techniques allows an IoT network to dynamically tune lifetime for signal distortion, according to the requirements dictated by the application
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