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Mobile edge computing is popular for providing services with low latency and high privacy. It becomes more powerful by leveraging the widely deployed Small cell Base Stations (SBS) with zooming cells for energy-efficient service placement. However, the literature ignores the joint optimization of SBS power control and service placement. The Quality of Services (QoS) guarantee is also challenging, taking into account the component dependency and parallelization in multi-component services and the resource slicing for separated service deployment. Moreover, prior works assume the same amount of allocated resources of links on a placed path for service edge allocation, leading to the ossification of resource allocation and inevitable resource fragments. Towards the above challenges, this paper addresses the energy-efficient and flexible service placement in cell zooming enabled Mobile Edge Cloud (MEC) networks. The delay of multi-component services is constructed depending on the allocated resource slice. Besides, the joint optimization of service placement and SBS power control is formulated and transformed into a Mixed Integer Linear Programming (MILP). More importantly, the equivalent bandwidth for an edge allocation is defined and analyzed to obtain flexible edge placement with minimum resource cost. Leveraging the results of MILP, an Energy-efficient Service placement algorithm based on equivalent Bandwidth in Cell zooming enabled MEC networks (ESBC) is proposed to improve the probability of successful service placement with QoS guarantee by optimizing the delay distribution among components and edges and reducing resource fragments. Finally, simulation results validate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

To overcome the Internet ossification, network virtualization has been proposed as a promising method because of its advantages (e.g., on-demand and efficient resource allocation). Virtual network embedding (VNE) is one of the main challenges for network virtualization. Energy costs of servers in data centers (DCs) aremajor contributions to the power consumption in information and communication technology. Therefore, VNE should consider both acceptance ratio and power consumption. In this paper, a mixed integer linear programming model is proposed with the objective of minimizing the total power consumption in software- defined optical data center networks by reducing the active data centers and power-consuming network components. In addition, the coordinates of nodes and delay of links are considered for a more realistic scenario. Compared with the existing node ranking method, the proposed global topology resource (GTR) can effectively evaluate the possibility of each DC node to host virtual nodes. Based on the GTR method, we propose a location-aware energy efficient VNE algorithm, namely GTR-VNE. Simulation results show that GTR-VNE can obtain up to 9.3% and 5% improvement of power consumption and acceptance ratio compared with benchmarks. Furthermore, based on GTR and artificial intelligence ant colony optimization (ACO), another energy efficient algorithm, ACO-VNE, is proposed.ACO-VNE can obtain up to 28.7% improvement in power consumption compared with GTR-VNE. In addition, ACO-VNE has better performance in terms of revenue cost ratio and acceptance ratio. [ABSTRACT FROM AUTHOR]

Abstract?Hybrid fiber-wireless (FiWi) networks, which benefit from high bandwidth and ubiquitous access of optical and wireless networks, have been identified as a promising technology candidate for next-generation broadband access. As various component/fiber failures may occur in hybrid FiWi networks, thus affecting huge numbers of end users, survivability has become one of the key important deployment considerations in such networks. This paper focuses on developing optimal network planning strategies to achieve survivable hybrid FiWi networks. In particular, to address the additional cost involved in deploying backup fibers in previously proposed redundancy strategies against distribution fiber failures, we propose the use of wireless routing through the ubiquitous wireless coverage of end users in a hybrid FiWi network. We present an optimization framework to optimally plan and deploy a survivable hybrid FiWi network, where traffic from an affected optical network unit (ONU) can be effectively rerouted to backup ONUs through wireless connections in the event of a distribution fiber failure. However, focusing only on the resilience of a network without considering its cost, and ignoring the resultant capacity, latency, and coverage under normal and protection operating conditions, is impractical. Our proposed framework therefore ensures maximum end-user coverage whilst satisfying survivability, connectivity, delay, and capacity constraints of the network, by optimizing the placement of passive optical splitters, ONUs, and wireless routers in conjunction with fiber and wireless connections. Moreover, we demonstrate the feasibility of our framework in the context of an urban deployment under different deployment scenarios. In particular, our results provide insight into how survivable FiWi networks can be deployed without compromising on the latency, coverage, and capacity requirements of such networks. [ABSTRACT FROM PUBLISHER]

Due to the massive deployment of electrical network devices, Fiber-Wireless (FiWi) access network has to suffer from the challenge of high energy consumption. With the ever-increasing eager for green communication infrastructure, the issue of high energy consumption may become one of the major barriers for the advance of FiWi access network. Previous works proposed for green FiWi access network cover three aspects, including the optimized deployment of network devices such as optical network units (ONUs), the energy-efficient bandwidth allocation of ONUs with QoS guarantee, and the dynamic power states scheduling of ONUs (i.e., active/sleep) according to their traffic profile. However, these works did not take the energy-saving design of wireless subnetwork into account simultaneously. In fact, when some ONUs in the optical subnetwork are switched into sleep states, part of the radio interfaces originally forwarding traffic to the sleep ONUs would be idle or low-loaded. This provides a potential opportunity for energy-saving in wireless subnetwork by switching off the idle or low-loaded radios. This paper focuses on the design of green multi-radio FiWi access network by integrating the energy-savings of optical and wireless subnetworks. To support the energy-efficient design, the new power states are defined for ONUs and radios, respectively. Aiming at dynamic traffic profile, the heuristic algorithms are proposed for the energy saving of integrated wireless front-end and optical back-end of FiWi access network. First, the Energy-saving algorithm with ONU sleep mechanism (EAS) is proposed to dynamically schedule the power states of ONUs by judging their traffic profile with load thresholds. Then, the Energy-saving algorithm based on Radios Off (ERO) is proposed to reconfigure the topology of wireless subnetwork by controlling the power states of radios dynamically. Moreover, wireless rerouting is employed in both EAS and ERO to guarantee the QoS provisioning ability of network. Finally, a comprehensive energy-saving scheme called EE is proposed by combining the EAS and ERO algorithms strategically. Simulation results show that with the reasonable setting of parameters, the proposed EE scheme can save the energy of 33.14% to 64.35% and 8.56% to 36.42% in a wide range of traffic load compared to the No-energy-saving and QoS-aware energy-saving scenarios, respectively. [ABSTRACT FROM PUBLISHER]

With the development of WDM techniques and cloud computing, incorporating the optical backbone into data centers has received extensive attention. Virtual network (VN) planning has been proposed for this new networking paradigm by taking advantage of network virtualization. VN planning is essentially a united virtualization of optical and server resources in a collaborative manner. In this article, we first elaborate the advantages and problems of existing VN planning schemes through a comprehensive survey. Next, we provide a VN planning scheme. The simulation results demonstrate the effectiveness of our strategy, particularly in the context of power outage and evolving recovery. Finally, the future opportunities and challenges are also discussed. [ABSTRACT FROM PUBLISHER]

Survivability is one of the key issues in fiber-wireless (FiWi) access networks, since network component failure may cause huge data loss. Especially in the scenario of segment failure, all optical network units (ONUs) lose their connections with the optical line terminal. Previous works focus on the protection of FiWi against segment failure by deploying backup fibers among the backup ONUs in different segments. However, these works consider only single segment failure. They also ignore the issue of traffic recovery efficiency. More importantly, they underutilize the backup fibers and ignore optimizing the selection of backup ONUs. Therefore, these works usually require a considerable deployment cost for backup fibers. To conquer these challenges, we propose an efficient protection scheme called cluster-based protection (CBP) in this paper. In CBP, we first partition the segments in the network into clusters in order to reduce the overhead for the management of traffic recovery. Then, we select one of the ONUs in each segment as the backup ONU and deploy backup fibers among the backup ONUs of different segments in the same cluster. Under a constraint on the maximum number of segments in each cluster, the CBP scheme aims to protect FiWi against the simultaneous failures of multiple segments with a minimum deployment cost for backup fibers. We propose both an integer-linear-programming-based approach and a heuristic approach to solve the joint optimization problem in CBP of selecting backup ONUs, clustering segments, and deploying backup fibers. To the best of our knowledge, this paper is the first work regarding the survivability of FiWi against the simultaneous failures of multiple segments. Through extensive simulation, we demonstrate that our CBP scheme outperforms the previous works significantly in terms of survivability enhancement and cost savings. [ABSTRACT FROM PUBLISHER]