Many researches show that the power consumption of network devices of ICT is nearly 10% of total global consumption. While the redundant deployment of network equipment makes the network utilization is relatively low, which leads to a very low energy efficiency of networks. With the dynamic and high quality demands of users, how to improve network energy efficiency becomes a focus under the premise of ensuring network performance and customer service quality. For this reason, we propose an energy consumption model based on link loads, and use the network’s bit energy consumption parameter to measure the network energy efficiency. This paper is to minimize the network’s bit energy consumption parameter, and then we propose the energy-efficient minimum criticality routing algorithm, which includes energy efficiency routing and load balancing. To further improve network energy efficiency, this paper proposes an energy-efficient multi-constraint rerouting (E2MR2) algorithm. E2MR2 uses the energy consumption model to set up the link weight for maximum energy efficiency and exploits rerouting strategy to ensure network QoS and maximum delay constraints. The simulation uses synthetic traffic data in the real network topology to analyze the performance of our method. Simulation results that our approach is feasible and promising.

Energy-Efficient Multi-Constraint Routing Algorithm With Load Balancing for Smart City Applications

We study the problem of the energy-efficient networking in cloud services with geographically distributed data centers for industrial Internet-of-Things (IIoT) networks, specially for multimedia IIoT networks. This is significantly challenged by dynamic end-to-end request demands and unbalanced link energy efficiency, unbalanced and time-varying link utilization, and bandwidth and delay constraints for service requirements. To solve these issues, we propose a multi-constraint optimization model for the energy efficiency optimization in cloud computing services where data centers are geographically distributed and are interconnected by cloud networks. Our model jointly optimizes energy efficiency in data centers and cloud networks. An intelligent heuristic algorithm is presented to solve this model for dynamic request demands between different data centers and between data centers and users. This is implemented by combining the niche genetic algorithm and the random depth-first search. Simulation results for energy-efficient networking show that better gains in network energy efficiency can be achieved by our joint optimization. Joint optimization between industrial data centers and industrial cloud networks can further improve energy savings and link utilization for time-varying requests.

An Energy-Efficient Networking Approach in Cloud Services for IIoT Networks

Earning an income in our time often involves ownership of or control over creative assets. Employing the law and philosophy of economics, this illuminating book explores the legal controversies that emerge when authors, singers, filmmakers, and social media barons leverage their rights into major paydays. It explores how players in the entertainment and technology sectors articulate claims to an ever-increasing amount of copyright-protected media. It then analyzes efforts to reform copyright law, in the contexts of 1) increasing the rights of creators and sellers, and 2) allocating these rights after employment and labor disputes, constitutional challenges to intellectual property law, efforts to legalize online mashups and remixes, and changes to the amount of streaming royalties paid to actors and musicians. This work should be read by anyone interested in how copyright law - and its potential reform - shapes the ownership of ideas in the social media age.

Copyright Class Struggle: Creative Economies in a Social Media Age

Innovations in ‘sustainable’ photonics technologies such as free-space optical links and solar-powered equipment provide developing countries with new cost-effective opportunities for deploying future-proof telecommunication networks.

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Tackling Africa's digital divide

In the Internet of Things (IoT), a huge number of sensors, actuators and other equipment for data acquisition and processing will be interconnected by means of an omnipresent communication network able to efficiently support heterogeneous transmission technologies and applications. On the one hand, advanced optical communication systems, which already play a significant role in modern networks, are currently evolving to meet very high requirements of modern applications. On the other hand, there are already many ways to utilize optical components and effects for building precise, efficient, and reliable sensors. Thus, optical technologies have the potential to greatly help in realizing future smart infrastructures and systems. This paper gives an overview of currently available and emerging optical technologies for sensing and communication applications and reviews their possible application in the context of the IoT for realizing smart systems and infrastructures.

https://www.mdpi.com/2224-2708/8/3/47/pdf

A Survey on Optical Technologies for IoT, Smart Industry, and Smart Infrastructures

The growing popularity of cloud and multimedia services is dramatically increasing the traffic volume that each data center needs to handle. This is driving the demand for highly scalable, flexible, and energy-efficient networks inside data centers, in particular for the edge tier, which requires a large number of interconnects and consumes the dominant part of the overall power. Optical fiber communication is widely recognized as the highest energy- and cost-efficient technique to offer ultra-large capacity for telecommunication networks. It has also been considered as a promising transmission technology for future data center applications. Taking into account the characteristics of the traffic generated by the servers, such as locality, multicast, dynamicity, and burstiness, the emphasis of the research on data center networks has to be put on architectures that leverage optical transport to the greatest possible extent. However, no feasible solution based on optical switching is available so far for handling the data center traffic at the edge tier. Therefore, apart from conventional optical switching, we investigate a completely different paradigm, passive optical interconnects, and aim to explore the possibility for optical interconnects at the top of the rack. In this article, we present three major types of passive optical interconnects and carry out a performance assessment with respect to the ability to host data center traffic, scalability, optical power budget, complexity of the required interface, cost, and energy consumption. Our results have verified that the investigated passive optical interconnects can achieve a significant reduction of power consumption and maintain cost at a similar level compared to its electronic counterpart. Furthermore, several research directions on passive optical interconnects have been pointed out for future green data centers.

Optical interconnects at the top of the rack for energy-efficient data centers

In this paper, we conduct systematic measurement studies to show that the high memory bandwidth consumption of modern distributed applications can lead to a signiﬁcant drop of network throughput and a large increase of tail latency in high-speed RDMA networks. We identify its root cause as the high contention of memory bandwidth between application processes and network processes. This contention leads to frequent packet drops at the NIC of receiving hosts, which triggers the congestion control mechanism of the network and eventually results in network performance degradation. To tackle this problem, we make a key observation that given the distributed storage service, the vast majority of data it receives from the network will be eventually written to high-speed storage media (e.g., SSD) by CPU. As such, we propose to bypass host memory when processing received data to completely circumvent this performance bottleneck. In particular, we design Lamda, a novel receiver cache processing system that consumes a small amount of CPU cache to process received data from the network at line rate. We implement a prototype of Lamda and evaluate its performance extensively in a Clos-based testbed. Results show that for distributed storage applications, Lamda improves network throughput by 4.7% with zero memory bandwidth consumption on storage nodes, and improves network throughput by up 17% and 45% for large block size and small size under the memory bandwidth

Lamda: The Last Mile of the Datacenter Network Does matter

Datacentres are experiencing a tremendous increase in the amount of network traffic due to cloud services and many other emerging applications. It is expected that the required bandwidth for an exascale supercomputer node will grow 20 times every 4 years (i.e., 20Pb/s in 2016 and 400Pb/s in 2020) [1]. However, the total power consumption that can be afforded by one datacentre is only allowed to increase at a much lower rate (i.e., 2 times every 4 years, 10MW in 2016 and 20MW in 2020) due to thermal dissipation constraints [1]. The consumers of energy in datacentres are IT equipment (e.g. servers, network equipment, etc.) and other supporting facilities (e.g. lighting, cooling, etc.). In order to identify how efficiently a datacentre uses its power, a measure called power usage effectiveness (PUE) is defined as the ratio of the total facility power to the IT equipment power. Many efforts have been put on reducing PUE. For instance, a smart selection of datacentre location could greatly reduce the energy required for cooling and significantly improve PUE. It was very recently reported that Facebook carefully chose the location and launched Arctic datacentre (consisting of three 28,000 square-meter buildings) in Sweden [2]. By utilizing icy conditions in the Arctic Circle, their datacentre can reach a PUE around 1.07 [2]. Such a low level of PUE implies that in modern datacentres major focus on energy savings should be moved to IT equipment. Currently, network equipment in a datacentre may take up to approximately 20% of the total energy consumed by IT equipment and this value is expected to grow in the future [3]. Thus, in order to sustainably handle ever-increasing traffic demand it becomes of extreme importance to address the energy consumption issue in datacentre networks (DCNs), which provide interconnections among different servers within a datacentre as well as interfaces to the Internet. Typically, DCNs include several tiers, namely edge, aggregation and core. In order to reduce energy consumption and increase bandwidth, the majority of the research efforts so far have been focusing on optical interconnects (e.g., reviewed in [1]) for core/aggregation tiers (i.e., switching among different racks). It should be noted that the power consumed by the switches at the edge tier (i.e., at the top of the rack ToR), which interconnect the servers located in the same rack, is dominant (up to 90% of the total power consumed by all types of switches in DCNs [4]) because of a huge number of ToR switches. Therefore, improving energy-efficiency at the level of ToR should be considered in the first place in order to decrease the overall DCN power consumption. Optical interconnects can be used to increase the energy efficiency at the ToR. On the other hand, to design proper optical interconnects at ToR it is of high importance to understand the characteristic of the traffic generated by the servers and its specific requirements. A number of key points (such as traffic locality, multicast capability, variable flow capacity, burstiness, etc.) that are summarized from the literature [5-7] should be taken into account. However, there have been very few studies on this problem. Therefore, we would like to discuss and compare several possibilities based on optical solutions, which can offer dynamic and flexible optical connections for datacentre traffic within the rack.

Yu Gong

Papers

Optical interconnects at the top of the rack for energy-efficient data centers

Lamda: The Last Mile of the Datacenter Network Does matter

High capacityl and energy efficient optical interconnects at top of the rack in datacentres