The GCA-w model (Global Cellular Automata with write access) is an extension of the GCA (Global Cellular Automata) model, which is based on the cellular automata model (CA). Whereas the CA model uses static links to l...
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The GCA-w model (Global Cellular Automata with write access) is an extension of the GCA (Global Cellular Automata) model, which is based on the cellular automata model (CA). Whereas the CA model uses static links to local neighbors, the GCA model uses dynamic links to potentially global neighbors. The GCA-w model is a further extension that allows modifying the neighbors' states. Thereby neighbors can dynamically be activated or deactivated. algorithms can be described more concisely and may execute more efficiently because redundant computations can be avoided. If the neighborhood of the GCA-w model is locally restricted, we will call the model "CA-w" (Cellular Automata with Write-access). Rotor-routing algorithms are good examples showing the usefulness of the CA-w model. The Propp-machine and the Chip-firing problem are first described by CA for comparison, and then by CA-w. It is shown that the CA-w descriptions are more concise, more "natural" compared to the CA descriptions, and more power saving because only the active cells have to be computed.
Open marketplaces of path services are the next step towards realizing "routing-as-a-service." Such marketplaces will enable users to select from a set of path services offered by multiple competing network ...
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ISBN:
(纸本)9781479966646
Open marketplaces of path services are the next step towards realizing "routing-as-a-service." Such marketplaces will enable users to select from a set of path services offered by multiple competing network providers so as to construct customized end-to-end paths for their applications. This is analogous to online travel marketplaces that allow users to explore travel options and book their travel. We review the requirements for path planners to assist users in stitching together available path services. We define the problem of finding multi-criteria time-constrained paths in this context, and present a dynamic programming algorithm that constructs Pareto-optimal paths.
The Internet research community is making a great effort in order to define efficient network management and, control functions. The goal is to make the best use of the network infrastructure, while meeting the users&...
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ISBN:
(纸本)9781424407385
The Internet research community is making a great effort in order to define efficient network management and, control functions. The goal is to make the best use of the network infrastructure, while meeting the users' requirements at the same time. One of the keys to achieve such a goal is the routing algorithm. A wide variety of traffic engineering and QoS routing algorithms have been proposed aiming to optimize resources and provide QoS to the users. However, the performace of such algorithms have usually been evaluated through simulations. In this paper, we present an architecture which enables to experiment with different routing algorithms in a real network. The performance of the routing algorithms can then be evaluated in terms of number of admitted flow requests, average delay, packet loss and jitter. We describe how we implemented all the components of the proposed architecture and how we setup a testbed consisting of Linux PCs. Finally, we illustrate an experiment we conducted to demonstrate the operation of our architecture.
Wireless Sensor Networks (WSN) have been noticed and researched nowadays. These new type of networks have unique characteristics. WSNs have different limitations such as computational power, storage capacity, energy s...
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ISBN:
(纸本)9781424427505
Wireless Sensor Networks (WSN) have been noticed and researched nowadays. These new type of networks have unique characteristics. WSNs have different limitations such as computational power, storage capacity, energy source and etc. The main constraint of wireless sensor networks is energy. The energy source of sensor nodes is limited and not rechargeable. Therefore, optimizing consumption of energy is essential for WSNs protocols. Hypercube topology is very popular in distributed environments. In last few years, many different topology specific routing algorithms have been designed for wireless sensor networks, but to the best of our knowledge, none of them consider Hypercube as their topology. In this paper, different routing algorithms are proposed for WSN with Hypercube topology. The performance of all proposed routing algorithms is evaluated, and the best algorithm which can provide more fairness is introduced. Simulation results which are represented in last section of this paper are the base of our conclusions. The main goal of this paper is to find a fair energy aware routing algorithm for wireless sensor network connected as Hypercube.
Network topology in Mobile Ad Hoc Networks is subject to constant/abrupt change. Source routing algorithms tend not to perform well due to this unstable topology, which invalidates the source routes often, however, th...
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ISBN:
(纸本)076951961X
Network topology in Mobile Ad Hoc Networks is subject to constant/abrupt change. Source routing algorithms tend not to perform well due to this unstable topology, which invalidates the source routes often, however, the changes in the topology are often local due to the continuous nature of physical movement of nodes. The hypothesis behind this work is that performance of source routing algorithm can be enhanced by localizing these changes in the source route due to mobility, called "Mobility Localization". Rest of the work discusses and evaluates this hypothesis.
High performance interconnection networking is one of the most active research fields in the area of communications. Their quick development has been increased by the interest in using multiple workstations in paralle...
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ISBN:
(纸本)3540641408
High performance interconnection networking is one of the most active research fields in the area of communications. Their quick development has been increased by the interest in using multiple workstations in parallel processing. These local networks use ideas that are already successfully applied in parallel computer interconnection networks. However, their more flexible and dynamic environment exposes new problems, such as topology configuration and message routing, which are difficult to solve with the current methods used in regular networks. Therefore, it is advisable to apply tools that kelp the researcher to develop and verify the behavior of new algorithms for these new networks. Nowadays, the RAAP group (Redes y Arquitecturas de Altas Prestaciones, High Performance Networks and Architectures) of the University of Castilla-La Mancha is working in this way. In this paper, we present a software tool developed by the RAAP group with the aim of helping in the research. It does not try to simulate the communications within the network (where a long computation process would not be able to guarantee none of its properties) but to analyze its behavior, through the channel dependency graph. The result is an agile and practical tool that provides conclusions in a quick and reliable way.
routing algorithms for wireless sensor networks are often evaluated through simulations in order to measure the lifetime of the network and the efficiency of the algorithm regarding energy consumption. Some particular...
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ISBN:
(纸本)9781467355018;9781467354998
routing algorithms for wireless sensor networks are often evaluated through simulations in order to measure the lifetime of the network and the efficiency of the algorithm regarding energy consumption. Some particular communication models with their parameters' set are used to implement the simulation and are rarely identical. We exhibit two kinds of performance sensitivity regarding simulations: the first one concerns the communication model itself and the second one is generated by the parameters of the communication model. We provide a generalized model that covers very different situations and we state the routing problem as a linear programming problem in order to measure the absolute efficiency of the algorithms with different models and parameter values. Our experiments run using two routing protocols, LEACH and Flow Augmentation, showed that different models or parameters can lead to significantly different results and conclusions. We tried to characterize the origin of the performance sensitivity in each case.
Networks of workstations (NOWs) axe becoming an increasingly popular alternative to parallel computers for those applications with high needs of resources such as memory capacity and input/output storage space, and al...
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ISBN:
(纸本)3540411283
Networks of workstations (NOWs) axe becoming an increasingly popular alternative to parallel computers for those applications with high needs of resources such as memory capacity and input/output storage space, and also for small scale parallel computing. Although the mean time between failures (MTBF) for individual links and switches in a NOW is very high, the probability of a failure occurrence dramatically increases as the network size becomes larger. Moreover, there axe external factors, such as accidental link disconnections, that also can affect the overall NOW reliability. Until the faulty element is replaced, the NOW is functioning in a degraded mode. Thus, it becomes necessary to quantify how much the global NOW performance is reduced during the time the system remains in this state. In this paper we analyze the performance degradation of networks of workstations when failures in links or switches occur. Because the routing algorithm is a key issue in the design of a NOW, we quantify the sensitivity to failures of two routing algorithms: up*/down* and minimal adaptive routing algorithms. Simulation results show that, in general, up*/down* routing is highly robust to failures. On the other hand, the minimal adaptive routing algorithm presents a better performance, even in the presence of failures, but at the expense of a larger sensitivity.
There are several routing algorithms that can be used in the context of Software Defined Networking (SDN), where a logically centralized controller obtains the global view of the network and network state information,...
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ISBN:
(纸本)9781538655535
There are several routing algorithms that can be used in the context of Software Defined Networking (SDN), where a logically centralized controller obtains the global view of the network and network state information, makes the routing decisions, and installs them to the switches in the selected paths. Comparing the performance of the existing routing algorithms under realistic simulation scenarios and understanding the factors that impact their performance are very important for their adaption in practice. Accordingly, we implemented several existing routing algorithms using RYU SDN controller and evaluated their performance on Mininet emulator. We considered three categories of routing algorithms with Static Link Cost (RA-SLC), Dynamic Link Cost (RA-DLC), and Dynamic Link cost with Minimum Interference (RA-DLCMI) under both the idealistic case assuming the availability of accurate network state information (NSI) and the practical case where the NSI is collected periodically and has some inaccuracy. Our experimental results showed that both RA-DLC and RA-DLCMI outperformed RA-SLC in terms of throughput and the number of accepted flows while there was no significant difference between RA-DLC and RA-DLCMI. We also observed that periodic collections caused inaccuracies in NSI and negatively affected the performance of all algorithms.
The cellular network systems are expected to evolve into Multi-hop Cellular Network (MCN). While a mobile terminal and the base station have a direct connection in a conventional cellular network, in MCN a mobile term...
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ISBN:
(纸本)9780769527772
The cellular network systems are expected to evolve into Multi-hop Cellular Network (MCN). While a mobile terminal and the base station have a direct connection in a conventional cellular network, in MCN a mobile terminal may reach the base station via relays by using multi-hopping. The relay can be either mobile terminal referred to client relay or dedicated relay referred to infra relay that has capabilities like those of the base station. In this paper, we focus on routing mechanism in multi-hop cellular networks. In particular, we study routing performance metrics for multi-hop cellular networks which consider energy efficiency and the relay capabilities.
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