In a software-defined network, a powerful central controller provides a flexible platform for defining network traffic through the use of software. When SDN is used in a large-scale network, the logical central controller comprises multiple physical servers, and multiple controllers must act as one to provide transparent control logic to network applications and devices. The challenge is to minimize the cost of network state distribution. To this end, we propose Distributed ZTE Elastic Network Intelligent Controller (DZENIC), a network-control platform that supports distributed deployment and linear scale-out. A dedicated component in the DZENIC controller provides a global view of the network topology as well as the distribution of host information. The evaluation shows that balance complexity with scalability, the network state distribution needs to be strictly classified.

In recent years, the number and size of data centers and cloud storage systems has increased. These two corresponding trends are dramatically increasing energy consumption and disk failure in emerging facilities. This paper describes a new chunk-based proportional-power layout called CPPL to address the issues. Our basic idea is to leverage current proportional-power layouts by using declustering techniques. In this way, we can manage power at a much finer-grained level. CPPL includes a primary disk group and a large number of secondary disks. A primary disk group contains one copy of available datasets and is always active in order to respond to incoming requests. Other copies of data are placed on secondary disks in declusterd way for power-efficiency and parallel recovery at a finer-grained level. Through comprehensive theoretical proofs and experiments, we conclude that CPPL can save more power and achieve a higher recovery speed than current solutions.

Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing (OFDM) systems. To counter this problem, a new wireless transmission technology based on Zero-Padding Carrier Interferometry OFDM (ZP-CI/OFDM) is proposed. In a ZP-CI/OFDM system, transmission symbols are spread to all OFDM subcarriers via carrier interferometry codes. This reduces the Peak-to-Average Power Ratio (PAPR) that traditional OFDM suffers and also exploits frequency diversity gain. By zero-padding at the transmitter, advanced receiver technologies can be adopted for ZP-CI/OFDM so that frequency diversity gain can be further utilized and the power efficiency of the system is improved.