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Wireless sensor networks (WSNs) have emerged as a one of the most fascinating areas of lookup in the past few years principally due to its massive quantity of workable applications. However limited energy, node deployment strategy, routing techniques has considerable impact on the overall performance of network. This paper proposes sustainable honey bee ratel based hybrid wireless sensor network (SHHWSN) layering framework for improving load balancing and scalability issues in network. In SHHWSN tessellated hexagonal shape clusters are formed to cover entire geographical region without any gaps. Hybrid routing schema constrained with redundant data identification policy used in this, seeks to optimize energy utilization. The proposed SHHWSN was evaluated and validated by simulation, and the results were compared with earlier schematics where mostly one sided stochastic node deployments were followed. The experimental results show that SHHWSN has superior performance in terms of network alive nodes, delay, energy and throughput. The proposed SHHWSN obtained values of 50 nodes is 3, 0.061, 0.14, 0.89, 100 nodes is 3,0.037, 0.19, 0.551, 150 nodes is 13, 0.081, 0.23, 0.415, and 200 nodes is 23, 1.01, 0.25, 0.356, which is significantly more effective than current techniques. [ABSTRACT FROM AUTHOR]

Wireless Sensor Networks (WSN) play a major role in the wide variety of applications like underground pipeline and leaks monitoring, temperature distribution monitoring in industrial cyber systems, military, forest life monitoring, and environmental and geographical monitoring. Sensors are widely used in these different applications. The number of sensors and the application concerned mainly decides the energy consumption, network lifetime. In this process relay nodes may help the sensors as backbone to connect with sink node or base stations. In this paper, we introduce a new approach for relay node selection in WSN to minimize the energy consumption of the network. It uses channel aware relay selection technique using game theory optimization and act as a virtual backbone in connecting to the base station. However, the relay nodes are varied to check the optimal number of relays required for the small, medium and large number of nodes deployed in the network. Simulations are carried out using Network Simulator NS-2.35 and network is analyzed in wide variety of scenarios. Results show that the proposed relay node selection algorithm reduces energy consumption, improves lifetime, throughput of the network. [ABSTRACT FROM AUTHOR]

With escalating demands for high-definition video, cache collaboration allows neighbor nodes to share locally stored content in order to reduce download traffic. High energy consumption associated with content delivery remains a concern for Content Distribution Networks (CDNs). Therefore, this paper proposes cluster-based collaborative caching in a core network employing IP over WDM. The aim is to allow sets of core caches to fully share content while minimizing power. A Mixed Integer Linear Programming (MILP) model is used to form energy-efficient cache clusters. The energy consumption of the network is evaluated under different cluster sizes to find the optimum size that minimizes energy. To evaluate the influence of content popularity distribution, a heavy-tailed Zipf distribution and an Equal popularity distribution are evaluated. In addition, the work investigates the influence of downlink traffic behavior and power consumption parameters on optimum cluster sizes. Attained results reveal that maximum savings in energy consumption introduced by cluster-based collaborative caching are up to 34.3% and 21.8% under the Zipf and Equal distribution, respectively. Cache collaboration is not recommended when all core nodes contain fully replicated content servers. Results also show that power consumption parameters do not influence cluster formation. It is recommended keeping cache collaboration in the core network simple, so as to reduce intra-cluster communication. [ABSTRACT FROM AUTHOR]

Today, continuous technical and emerging advances between power communication systems and smart grids and applying swarm intelligence have increased for data sharing and analytics in our life. On the other side, Internet of things (IoT) has important key role to establish constructive interactions between smart devices and smart grid and power communication applications. For enhancing data transformation and improvements of multi-objective Quality of Service (QoS) factors, Swarm Optimization Techniques (SOT) are applied simultaneously in a cooperative smart environment to solve NP-hard problems. This paper provides a comprehensive analysis to address a new technical taxonomy and categorization of existing SOT-based smart grid applications in power communication systems in the IoT. Also, existing service and resource management case studies on smart grids and power communication systems are briefly analyzed and discussed. Existing evaluation factors on smart grid applications using SOT are represented. Possible advantages and weaknesses of each category are discussed with respect to new challenges and open research directions. [ABSTRACT FROM AUTHOR]

Internet of Vehicles (IoV) presents a new generation of vehicular communications with limited computation offloading, energy and memory resources with 5G/6G technologies that have grown enormously and are being used in wide variety of Intelligent Transportation Systems (ITS). Due to the limited battery power in smart vehicles, the concept of energy consumption is one of the main and critical challenges of the IoV environments. Optimizing resource management strategies for improving the energy consumption using AI-based methods is one of important solutions in the IoV environments. There are various machine learning algorithms for selecting optimal solutions for energy-efficient resource management strategies. This paper presents the existing energy-aware resource management strategies for the IoV case studies, and performs a comparative analysis among their applied AI-based methods and machine learning algorithms. This analysis presents a technical and deeper understanding of the technical aspects of existing machine learning and AI-based algorithms that will be helpful in design of new hybrid AI approaches for optimizing resource management strategies with reducing their energy consumption. [ABSTRACT FROM AUTHOR]

In current information systems, a huge number of IoT (Internet of Things) devices are interconnected with various kinds of networks like WiFi and 5G networks. A large volume of data is gathered into servers from a huge number of IoT devices and is manipulated to provide application services. Gathered data is encapsulated along with methods to manipulate the data as an object like a database system. In object-based systems, each application is composed of multiple objects. In addition, each object is replicated on multiple physical servers in order to increase availability, reliability, and performance of an application service. On the other hand, replicas of each object is required to be mutually consistent in presence of multiple transactions. Here, a larger amount of electric energy and computation resources are consumed in physical servers than non-replication approaches to serialize conflicting transactions on multiple replicas. Many algorithms to synchronize conflicting transactions are so far proposed like 2PL (Two-Phase Locking) and TO (Timestamp Ordering). However, the electric energy consumption is not considered. In this paper, an EEQBL-OMM (Energy-Efficient Quorum-Based Locking with Omitting Meaningless Method) protocol is newly proposed to reduce not only the average execution time of each transaction but also the total electric energy consumption of servers by omitting the execution of meaningless methods on replicas of each object. Evaluation results show the total electric energy consumption of servers, the average execution time of each transaction, and the number of aborted instances of transactions in the EEQBL-OMM protocol can be on average reduced to 79%, 62%, and 80% of the ECLBQS (Energy Consumption Laxity-Based Quorum Selection) protocol which is proposed in our previous studies in a homogeneous set of servers, respectively. In addition, the evaluation results show the total electric energy consumption of servers, the average execution time of each transaction, and the number of aborted instances of transactions in the EEQBL-OMM protocol can be on average reduced to 73%, 50%, and 67% of the ECLBQS protocol in a heterogeneous set of servers, respectively. The evaluation results also show at most 48% and 51% of the total number of methods can be omitted as meaningless methods in a homogeneous set and heterogeneous set of servers, respectively, in the EEQBL-OMM protocol. [ABSTRACT FROM AUTHOR]

Due to the mobility and frequent topology changes, routing the data poses a challenging issue in the Internet of Things (IoT). Security poses a fundamental requirement factor in most IoT applications particularly, secure routing among the IoT nodes. The aim of this paper is to develop secure routing in IoT with minimal delay, minimal energy consumption and high throughput. Thus, a new algorithm, named Rider Foraging Optimization algorithm (RFO) is designed by the incorporation of standard Rider Optimization algorithm (ROA) and Bacterial Foraging optimization algorithm (BFO) that render an optimal solution, which is the optimal path for transmitting the information. Initially, the trust of the nodes is evaluated and the cluster head (CH) is chosen based on Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol to securely transmit the data. Then, the proposed RFO algorithm selects the optimal path using the fitness factors, such as trust, energy, and delay constraints. The results revealed that the energy consumption of the nodes is reduced and the lifetime of the network is enhanced through the implementation of the proposed RFO, which attained a maximal throughput of 1, and minimal delay and energy consumption of 0.1169 and 0.0002, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the new throughput analysis of the adaptive three modes for Packet Combining (PC), Modified Packet Combining (MPC) and Aggressive Packet Combining (APC) techniques. The three modes in this paper consist of X (low probability of packet error), Y (moderate probability of packet error) and Z (high probability of packet error) channel states. The three states are based on the number of received acknowledgement (either positive acknowledgement (ACK) or negative acknowledgement (NACK)) by Transmitter (Tx). The PC, the hybrid PC+MPC and the hybrid MPC+APC techniques are implemented in X, Y and Z channel states respectively for enhancing the fast error correction and also to reduce retransmission of duplicate copies. Thus, the proposed protocol is simulated using MATLAB and the results yield better performance over conventional PC, MPC and APC techniques in terms of throughput, the probability of packet error correction and energy consumption. [ABSTRACT FROM AUTHOR]

In the wireless sensor network (WSN), wireless communication is said to be the dominant power-consuming operation and it is a challenging one. Virtual Multiple-Input–Multiple-Output (V-MIMO) technology is considered to be the energy-saving method in the WSN. In this paper, a novel multihop virtual MIMO communication protocol is designed in the WSN via cross-layer design to enhance the energy efficiency, reliability, and end-to-end (ETE) and Quality of Service (QoS) provisioning. On the basis of the proposed protocol, the optimal set of parameters concerning the transmission and the overall consumed energy by each of the packets is found. Furthermore, the modeling of ETE latency and throughput of the protocol takes place with respect to the bit-error-rate (BER). A novel hybrid optimization algorithm referred as Flight Straight Moth Updated Particle Swarm Optimization (FS-MUP) is introduced to find the optimal BER that meets the QoS, ETE requirements of each link with lower power consumption. Finally, the performance of the proposed model is evaluated over the extant models in terms of Energy Consumption and BER as well. [ABSTRACT FROM AUTHOR]

Network Lifetime (NL) is a pivotal issue in real time data monitoring using Wireless Sensor Network (WSN). In this paper, we propose a distributed MAC protocol for NL maximization based on spatial correlation and opportunistic transmission, which we named Spatial Correlation based Clustered Opportunistic Protocol (SCCOP). SCCOP employs a novel spatial correlation model to cleave the network into correlated clusters. The transmission scheduling in clusters is done according to NL maximization condition, which incorporates channel statistics of individual sensors into carrier sensing and backoff strategy. From each cluster, an energy-efficient sensor node with the best channel is scheduled to transmit its data directly to the access point (AP) as the representative node for the whole cluster. Accordingly, SCCOP achieves significant reduction in redundant data transmission as well as energy consumption in the wireless network. The simulation results show that as the node density in the network increases, SCCOP has better performance enhancement in terms of NL, throughput, energy saving and outage. [ABSTRACT FROM AUTHOR]

Geographic routing protocols in wireless sensor networks require providing location information of sinks to source nodes. Most studies have only focused on two-dimensional (2D) sensing field, but the real-world applications of sensor networks are in a three-dimensional (3D) environment. This paper presents a new scheme based on residual design principles for 3D networks. In this scheme, sink location announcement (SLA) and sink location query (SLQ) packets are forwarded along two blocks. The node located at the intersection of the two blocks sends the sink position to the source. In the proposed method, SLA and SLQ messages constructed using residual design blocks. For this purpose, the mapping from residual design to sink location service have been proposed. In order to analyze proposed algorithm's performance, a series of simulations have been conducted using the NS-2 network simulator. Simulation results indicate that proposed algorithm can significantly reduce the communication overhead and energy consumption. [ABSTRACT FROM AUTHOR]

Designing a routing protocol for opportunistic networks (OppNets) is a challenging task due to node's mobility and the lack of further knowledge about the network topology and the presence or not of an end-to-end path. This paper proposes an energy efficient routing protocol called Distance and Encounter based Energy-Efficient Protocol (DEEP), in which the selection of the best next hop forwarder for a message relies on the node's energy. Simulation results demonstrate that the proposed scheme outperforms E-Prophet, E-PRoWait and E-EDR, our energy-aware implementations of the Probabilistic Routing Protocol using History of Encounters and Transitivity (so-called Prophet), Probability-based controlled flooding in opportunistic networks (so-called PRoWait), and Encounter and Distance based Routing (so-called EDR) routing protocol, in terms of node's residual energy, number of dead nodes, message delivery probability, and message latency. [ABSTRACT FROM AUTHOR]

In order to realize the cooperation of a group of multiple nodes, messages have to be reliably and efficiently delivered to all of them, according to a traditional broadcasting paradigm, by also reducing the electric energy consumed by each involved node. In this paper, we propose three types of energy-efficient broadcast algorithms, namely EEB (energy-efficient broadcast), EEB2 (modified EEB), and AEEB (augmented EEB) whose objective is reducing the total electric energy consumed by nodes. In the EEB algorithm, a wireless link to a farthest child node is truncated until there is no other child node which can forward messages to it in a more energy-efficient way. In the EEB2 algorithm, a link to a farthest child node is truncated if there is another child node which can forward the message to it. In the EEB and EEB2 algorithms, a child node is selected for each parent node. On the other hand, one parent node is selected among possible parent nodes of each child node, which is nearest to the child node in the AEEB algorithm. We evaluate the EEB, EEB2, and AEEB algorithms and show that the total electric energy consumed by nodes can be reduced in the AEEB algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we propose a data propagation method with operator intent delivery in Wireless Sensor Networks (WSNs). The proposed algorithm propagates data by controlling the state of a sensor node depending on the delay requirements of a specific application. Also, the proposed algorithm allows users to interact with the WSNs to convey desired parameter values for the operations. Simulation results indicate that the proposed algorithm achieves reliable data propagation and user intent delivery while saving energy consumption. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) consist of a large number of tiny, low cost, memory/computational constraint, battery-operated sensor nodes deployed randomly in two (or three) dimensional plane. Due to limited amount of energy in sensors, the network seeks to attain energy efficient routing for prolonging their lifetime. Existing grid based routing protocols reduce the energy dissipation at nodes, however they suffer from congestion. Network congestion may lead to excessive energy consumption, which in turn minimizes the lifetime of network. In this paper, we propose a new Congestion Aware Lifetime Improving Routing Protocol (abbreviated shortly as CALIRP) for grid-based WSNs, which improves the network lifetime by minimizing congestion at nodes. In CALIRP, routing is conducted in a grid by grid manner through the cell-headers. To save the energy and avoid congestion, multiple routing paths are established from the source to the base station. The paths are selected based on Transmitting Factor (TF) of cell-headers which take queue occupancy, queue length and residual energy into account. In addition, CALIRP adjusts node's transmitting factor for reconstructing the paths so that the lifetime of network is prolonged. Simulation results highlight that the proposed CALIRP outperforms other existing routing algorithms in terms of success rate, queue occupancy and number of alive nodes etc. [ABSTRACT FROM AUTHOR]

Long Term Evolution (LTE) technology is becoming the de-facto NGN mobile access network. In order to deliver multimedia contents and services, higher data rates and low latency is required. The new planned LTE base stations can deliver on high data throughput at lower latency than available cellular networks. However, this deployment comes at an increased complexity of radio resources scheduling and power allocations. More than one half of the network operating cost comes from electrical energy. Therefore, one aim of the network operators is to reduce cellular networks power consumption. In this paper, a simulation study of three proposed scheduling algorithms are studied under base station flat power spectrum constraints. LTE cell deployment is evaluated and analyzed to maximize cell throughput, while preventing cell edge customers from starvation. Studying the performance of flat cell power requirements, cell coverage, resource scheduling and maximum throughput is another aim of this paper. Average service mean time is a concept we introduce as a measure of the system efficiency. [ABSTRACT FROM AUTHOR]

Delay-sensitive applications require the capability to send data while meeting performance requirements. However, due to strict constrains on the resources available to the sensor nodes, wireless sensor networks (WSNs) pose critical challenges in network protocol design considering delay constraints. Biologically inspired modeling techniques have received considerable attention for achieving robust global behavior, while retaining individual simplicity. In this paper, we propose an epidemic-inspired node scheduling scheme (ENS) with aims of delay reduction and energy saving. The ENS controls the state of a sensor node depending on the delay requirements of a specific application. Simulation results indicate that the ENS achieves reliable data delivery while saving energy consumption. [ABSTRACT FROM AUTHOR]

Bluetooth Low Energy (BLE) is a recently developed energy-efficient short-range radio communication technology, which is nowadays vastly becoming more and more popular. The technology aims to provide an energy-efficient low-cost wireless communication mechanism for a wide range of resource-limited consumer electronic devices and applications. In this paper we focus on the networking aspects of the technology. First, we overview fundamentals of BLE communication technology, discuss its capabilities and limitations, and compare BLE with state-of-the-art technologies. Furthermore, we identify and discuss two scenarios, for which standard BLE communication mechanisms show poor performance and propose two mechanisms capable of improving throughput and energy efficiency of BLE communication in multi node environment. The efficiency of the proposed mechanisms is proved via network level simulations, which are executed using the developed BLE simulation tool. The results of the simulations are reported and discussed. We believe that the presented results might be of some interest not only for academic researchers but also for practicing engineers. [ABSTRACT FROM AUTHOR]

Energy efficiency is considered as an important design issue in multihop wireless networks as the nodes are battery limited. Energy efficiency can be achieved by establishing multiple paths. Multipath routing explores multiple disjoint paths between sources-sink pair in order to improve energy consumption at nodes and thus, provide robustness against possible node failure. However, it remains a challenging task in wireless networks due to associated interference. Reducing interference lowers the energy consumption, improving the network lifetime. This paper proposes an interference aware energy efficient multipath routing protocol for a given source-sink pair by a combined route construction and power allocation method. After finding k-minimum weight node disjoint paths on a weighted communication graph, iterative power allocation is performed on the derived paths considering signal to interference plus noise ratio (SINR) model. The power allocation method minimizes the interference experienced by each node at an acceptable level so that multiple transmissions can take place simultaneously. By alternatively invoking multipath route construction and power allocation method on a weighted communication graph, the proposed algorithm optimizes the assignment of transmission power and thereby minimizes the total energy consumption on k-node disjoint multipath. The simulation results show that the performance of the proposed scheme is better than existing multipath routing algorithms. [ABSTRACT FROM AUTHOR]

Recently, MapReduce has been a popular distributed programming framework, which divides a job into map tasks and reduce tasks and executes these tasks in parallel over a large-scale MapReduce cluster to speed up job execution. Generally, the cluster is a master-slave infrastructure. To prevent jobs from being interrupted due to node failure, current MapReduce implementations, such as Hadoop, adopt a task-reexecution policy on the slave side, i.e., when a slave node due to failure cannot complete a task, this task will be reassigned to another available slave for reexecution. However, on the master side by default, no redundancy scheme is provided. Since this type of infrastructure has been worldwide adopted, we call it the general MapReduce infrastructure (GMI). To achieve a more reliable and energy-efficient working environment, understanding the impact of GMI on its job completion reliability (JCR) and job energy consumption (JEC) is required. In this paper, we base on a Poisson distribution to analyze GMI's JCR from a single-job perspective. After that, we accordingly derive the corresponding JEC. Through the analytical results, MapReduce managers can comprehend how GMI behaves and how their MapReduce can be improved so as to achieve a more reliable and energy-efficient MapReduce environment. [ABSTRACT FROM AUTHOR]

As various multimedia services are being provided on networks, broadband traffic is growing as well. Reducing traffic is important because power consumption in networks has been increasing year by year. Meanwhile, in-network caching for CCN (Content-Centric Networking) is expected to achieve an adaptive content delivery in the network and to reduce traffic by storing content data on each router. Therefore, in-network caching is beneficial in view of energy efficiency. However, in order to improve energy efficiency of the network, it is necessary to cache content appropriately in consideration of both power consumption of content caching and transmission of traffic. In this paper, we propose a design method which derives the most energy efficient cache locations of content and a distributed cache mechanism for CCN to search for energy efficient cache locations. Furthermore, we demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Nowadays, the energy consumption and efficiency of wireless networks have become a societal challenge. In this paper a novel system architecture is proposed to achieve green communications. The proposed smart social architecture exploits the flexibility and adaptability of cognitive radio (CR) technology to interact with the environment and achieve eco-sustainability by means of finding the best transmission opportunities. However, the effort required for CR nodes to obtain sensing measurements might make less effective the potential energy efficiency gain obtainable in CR networks. We thus propose to combine CR and social network technologies to maximize the energy efficiency and the associated context awareness in terms of energy and radio knowledge. In this way it is also possible to reduce the sensing burden of CR devices. Through the proposed approach, a greater awareness of environmental impacts by CR paradigm can be instilled in participating users, devices and backbones. This is based on a novel extension of the concept of social network, and specifically by allowing socialization among all the network actors, both users (as it is already done today) and cognitive devices to develop a much lighter and more flexible distributed infrastructure. The functionalities of the network elements and their interfaces are described in detail. [ABSTRACT FROM AUTHOR]

Recent studies show that malicious traffic has a significant impact on the behavior of networks, thus early dropping of malicious packets could enhance network performance. Furthermore, recent developments in the field of green networking show that it is possible to modulate power consumption according to the traffic level. Intrusion Detection Systems burden the basic routing task with packets inspection; however, traffic reduction could have beneficial results both on network performance and, with next generation routing devices, in network energy consumption. In this paper, we focus on energy consumption and we present an approach to distribute packet inspection over the network nodes, a model to evaluate the changes in network energy consumption according to early or late discovery and discard of rogue packets, and we adopt our technique and model to evaluate by means of simulation how aggressive distributed intrusion detection could be beneficial in terms of network energy savings. [ABSTRACT FROM AUTHOR]

In this paper, we propose an energy efficient and delay guaranteed node coordination scheme inspired by biological systems, which have gained considerable attention as a computing and problem solving technique. With the identification of analogies between biological cellular signaling systems and WSN systems, we formulate a new mathematical model that considers the networking challenges of WSNs. The proposed bio-inspired scheme determines the state of the sensor node, as required by each mission-critical application and as determined by the local environmental conditions. A control analysis and simulation results show that the proposed bio-inspired scheme guarantees the system stability and provides significant energy savings, as well as reliable delay guarantees. [ABSTRACT FROM AUTHOR]

This paper describes a rate flexible network transport solution to achieve sub-wavelength circuit provisioning between edge node pairs. Sub-wavelength circuits are obtained by concatenating spectrally efficient digital subcarrier channels along the network path, with each subcarrier frequency carrying only a fraction of the wavelength bandwidth. By reserving one or more such subcarrier frequencies along a path connecting two edge nodes, a dedicated end-to-end sub-wavelength circuit is provisioned. At an intermediate node, incoming frequencies are switched to outgoing frequencies via a cross-bar electronic circuit switch or cross-connect. By performing digital subcarrier multiplexing (DSCM) using CMOS based advanced digital signal processing (DSP) algorithms, spectral guard-bands between adjacent channels are not necessary, thus yielding good bandwidth efficiency when multiplexing multiple subcarrier channels onto the same wavelength. Compared to current TDM based transport network solutions, e.g., OTN/SONET/SDH, the described solution offers the unique advantage of implementing two key transport functionalities in the same DSP system, which is capable of (1) performing compensation of fiber transmission impairments in the electronic domain to ensure good signal integrity, and (2) multiplexing (demultiplexing) subcarrier channels after (before) add/drop and switching circuit operations. Because of this design advantage, system complexity and fabrication of the network equipment are ameliorated, possibly leading to tangible cost and electric power consumption reductions. [ABSTRACT FROM AUTHOR]

Hybrid optical switching (HOS) has the potential to provide highly efficient operation through combining various switching paradigms and different implementation options within the same network. The flexibility of choosing between circuit, packet or burst switching and electronic or optical implementation results in an improvement of both energy and data transport efficiency because the most appropriate method and less power consuming elements can be selected and used for transmission of data through the network while temporarily inactive elements are switched off or put in a low-power mode. In this paper, we introduce a novel network concept that we refer to as adaptive hybrid optical switching (AHOS) and present and investigate several architectures and realization options for AHOS nodes. The corresponding control plane comprises two layers, of which one implements routing, signalling and link management functions as defined in the GMPLS standard while the other is responsible for managing already established circuits and scheduling the transmission of packets and bursts. We present results on both performance and energy consumption for different AHOS node realizations, network configurations and traffic patterns, which prove the potential for a high improvement in energy efficiency with respect to conventional electronic packet-switched networks. [ABSTRACT FROM AUTHOR]

Increasing popularity of media-rich Internet content and the associated growth in power consumption have highlighted the need for energy efficient content distribution schemes. This paper investigates the power savings introduced by caching content in IP over WDM networks. To carry out the study, we develop a MILP model to minimize the power consumption of cache-based services over an IP over WDM network by optimizing the cache sizes of the network nodes at different times of the day. A Constraint-Based Genetic Algorithm (CBGA) is developed to validate the optimum cache sizes obtained from the MILP model and a simulation based on lightpath bypass validates the power consumption of routing traffic demands. We consider different popularity distributions including the Zipf, Pareto and Bimodal content popularity distributions to exemplify different types of IPTV services. Our results reveal that deploying the optimum variable cache sizes at the nodes reduces the overall network power consumption by up to 42%, 68% and 72% using Zipf, Pareto and Bimodal distributions for content popularity, respectively. We further study the impact of regular cache updates on power efficiency. The results show that removing the 10 most popular objects from caches increases the network power consumption by up to 20%. [ABSTRACT FROM AUTHOR]

Recently, the need for energy-efficient and sustainable capacity growth has become stringent for telecommunication networks and great efforts have been produced to reduce their power consumption. Optical technologies based on Wavelength Division Multiplexing are well-recognized as a promising solution for greening the future Internet. One relevant approach to achieve such power savings consists in aggregating traffic flows in few network links, so that power can be saved by switching-off some unused network devices. However, the need to ensure network resiliency against link and/or node failures imposes that still the resources reserved to protect connections become available immediately after a failure occurs. Therefore, a possible solution is to set some devices into low-power sleep-mode, so that they can be rapidly re-activated and provide fast connection recovery. In this paper we focus on the power-efficiency of protected IP-over-WDM networks and provide a comprehensive comparison of four different protection strategies, namely Shared-Link, Shared-Path, Dedicated-Link and Dedicated-Path Protection (SLP, SPP, DLP and DPP respectively) in a sleep-mode scenario. In the proposed design strategies we assume that low-power sleep-mode is enabled for devices used for protection. Mathematical models for a power-aware design with sleep-mode is proposed for the four protection strategies. We show that relevant power savings (up to about 60%) can be obtained for all the protection strategies by setting protection devices into sleep-mode. [ABSTRACT FROM AUTHOR]

Telecommunication networks are evolving due to rapid growth of internet traffic and the necessity to satisfy the new requirements of emerging packet services. Upgrading of network devices so as they can allow scalable and full line rate traffic aggregation and eliminate any internal performance bottlenecks is crucial. In packet switching devices, since data plane functionalities need to be executed for each incoming packet and power per given bandwidth is strongly related to the amount of processing on this data, packet processing at ultra-high rate is becoming the major challenge. The main trend to address such power consumption and scalability issues is to bypass packet switches by switching traffic at lower layers. This results in the packet optical transport network approach, where packet switching provides flexible end-to-end connectivity based on tunnel encapsulation while wavelength switching, exploiting optical bypass, allows reducing electrical switch size at transit nodes. There are also opportunities consisting in simplifying packet switch functionalities or designing completely different packet switch architectures. In this paper a new Ethernet aggregation and switching solution with potentialities to simplify and scale Ethernet switch forwarding functionality is proposed. This solution, based on a burst-basis transmission compliant with the Ethernet Standard, is able to maintain flexibility and any to any connectivity deriving from the connectionless nature of Ethernet. At the same time, it provides Ethernet technology with efficient aggregation capabilities allowing to reduce processing of transit traffic. This is allowed thanks to an Ethernet burst structure conceived as a variable number of consecutive frames of the same connection preceded by a proprietary burst control frame carrying information necessary for burst data frames classification. As a result, burst control frames experience the conventional Ethernet switch packet processing while data frames are mapped on the corresponding queue/output port according to the result of control frames classification. The proposed solution also provides the possibility to recognize data frames of the same burst through a proprietary inter-frame gap inserted among them; that allows to dynamically adapt burst size to the available bandwidth at transit nodes in order to limit frame delay and jitter and to support intermediate grooming. These features make it a very competitive approach in the context of packet optical transport being able to support dynamic multi-granular switching. The proposed solution has been validated by estimating its efficiency in terms of energy consumption with respect to a commercial packet switch. The impact of burst transmission on packet delay and jitter across ring and mesh networks has been also evaluated through different sets of simulations. [ABSTRACT FROM AUTHOR]

Over the past decade, the ever-increasing energy demands of IT infrastructures have posed significant challenges for the research community in terms of reducing their total power consumption and minimizing their environmental impact. Optical communication networks are envisioned to be promising candidates to help preventing this problem affecting the Internet backbone, as well as for distributed applications such as computational grids. In this paper, we propose an adaptive and distributed scheme for the establishment of energy-efficient lightpaths in computational grids. The grid is deployed over an optical circuit-switched backbone network, defining an optical grid network. Each node of the backbone network maintains two different dynamic thresholds values and estimates the changes in network performance by evaluating the moving average of the total wavelength channel occupancy on all its input/output links. The nodes have the ability of reducing the energy consumption by entering into an Energy Saving Mode (ESM) on the basis of a comparison between their channel occupancy and the thresholds. Furthermore, we extend our framework by allowing the thresholds to be dynamically adapted depending on the network performance in terms of blocking probability. We show that the proposed method achieves considerable energy savings when compared to a normal energy-unaware operational mode and still allows to maintain an acceptable level of network performance in terms of blocking probability and end-to-end delay. Numerical results are obtained with a Java event-driven simulator of two different optical network topologies. [ABSTRACT FROM AUTHOR]

Multicast transmission is utilized in Time Division Multiple Access (TDMA) Passive Optical Networks (PONs) to efficiently and selectively send downstream data to subsets of users. For example, multicast can be exploited in open access PONs to offer various services provided by different providers to the end-users. In this scenario, the minimization of the energy consumption, which is one of the greatest contributors to PON CAPEX, would benefit not only service providers but also end-users. This paper proposes an energy efficient multicasting solution based on energy efficient optical network units (ONUs). Energy savings are achieved by setting to sleep mode the ONUs that need not receive downstream data, i.e. are not subscribed to a multicast group. Sleep mode is combined with an optimal multicast group scheduling to minimize the transitions from sleep to active mode, which consume power for achieving synchronization. Results show that energy efficient multicast transmission reduces the energy consumption with respect to the current broadcast-based transmission. The improvement is more significant when only one user is connected to an ONU (i.e., FTTH) than when several users are connected to the same ONU (i.e., FTTB). This is due to the fact that the higher is the number of subscribers connected to an ONU the higher is the likelihood that an ONU must be active most of the time. [ABSTRACT FROM AUTHOR]

The paper provides estimates how deployment of fast fixed broadband may affect consumption of energy by subscriber's electronic devices. New subscribers are expected to buy additional equipment: PCs, laptops, TV sets, game consoles, etc. and more intensively use all devices connected to the net. The effects are independent of access technology, as long as certain key services are supported. Resulting increase of electricity consumption by households will likely require costly investment in new power plants. In case of fossil fuel power generation, negative environmental consequences will be noticeable. However, progress in reducing device power consumption and replacement of desktop PCs with laptops and other portable devices shall considerably mitigate these effects. [ABSTRACT FROM AUTHOR]

Operating costs and scalability of nowadays telecommunication networks are largely impacted by energy consumption of network equipments. In packet switching devices it is especially due to packet processing, queuing, and input/output interface functionalities. Different approaches to reduce energy consumption in packet switches are emerging, some exploit under-laid optical bypass of transit traffic to reduce their capacity and interfaces, others simplify their operations or turn off some of their functionalities when unnecessary. The IEEE standardization body developed a standard on Energy Efficient Ethernet (IEEE P802.3az) that defined a mechanism allowing to de-activate the Physical layer elements during periods of low link utilization. It is based on a protocol that coordinates transitions to and from a lower power consumption mode without changing the link status and dropping frames. Time needed by such transitions is, however, comparable with packet transmission time; that makes energy efficiency of the method far from being proportional to interfaces unused capacity. Solutions proposed in the literature to improve EEE performance are mainly based on the buffer and burst approach, which, making the transmission non continuous, creates more opportunities for long sleeping period. Such solutions, however, if applied across the network, strongly impact packet delay requirements. In this paper, a traffic management mechanism that controls sleeping period to reduce EEE transitions overhead while meeting delay constraints of data flows is proposed. Starting from the consideration that in Ethernet network provisioning is static, i.e. service level agreement parameters of each flow are configured on switches output ports of its path via management plane at the set-up phase, the proposed method off-line determines, for each output port, if the activation of a dummy flow, associated to the quiet period, can provide power consumption reduction without impacting data flows delay requirements. On ports where the dummy flow is activated the sleeping period is triggered by the scheduler mechanism each time a dummy packet is served. A comparative analysis between the standard EEE, with and without the support of buffer and burst functionality, and the proposed method has been carried out in order to quantify the improvements in terms of energy efficiency and to assess its effectiveness in terms of Quality of Service (QoS). [ABSTRACT FROM AUTHOR]