检索结果-南通市图书馆

Providing Guaranteed network performance across Tenants:Advances,Challenges and Opportunities

在线全文

学校读者我要写书评

暂无评论

China Communications 2021年第2期18卷 152-174页

作者： Chengyuan Huang Jiao Zhang Tao Huang Yunjie Liu State Key Laboratory of networking and Switching Technology BUPTBeijingChina Purple Mountain Laboratories NanjingChina

The varied network performance in the cloud hurts application performance.This increases the tenant’s cost and becomes the key hindrance to cloud adoption.It is because virtual machines(VMs)belonging to one tenant can reside in multiple physical servers and communication interference across tenants occasionally occurs when encountering network congestion.In order to prevent such unpredictability,it is critical for cloud providers to offer the guaranteed network performance at tenant level.Such a critical issue has drawn increasing attention in both academia and industry.Many elaborate mechanisms are proposed to provide guaranteed network performance,such as guaranteed bandwidth or bounded message delay across tenants.However,due to the intrinsic complexities and limited capabilities of commodity hardware,the deployment of these mechanisms still faces great challenges in current cloud datacenters.Moreover,with the rapid development of new technologies,there are new opportunities to improve the performance of existing works,but these possibilities are not under full discussion yet.Therefore,in this paper,we survey the latest development of the network performance guarantee approaches and summarize them based on their features.Then,we explore and discuss the possibilities of using emerging technologies as knobs to upgrade the performance or overcome the inherent shortcomings of existing advances.We hope this article will help readers quickly Received:Apr.07,2020 Revised:Oct.23,2020 Editor:Haifeng Zheng understand the causes of the problems and serve as a guide to motivate researchers to develop innovative algorithms and frameworks.

关键词： cloud computing network performance guaranteed bandwidth guaranteed delay

Virtual machine placement optimizing to improve network performance in cloud data centers

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2014年第3期21卷 62-70页

作者： DONG Jian-kang WANG Hong-bo LI Yang-yang CHENG Shi-duan State Key Laboratory of networking and Switching Technology Beijing University of Posts and Telecommunications

With the wide application of virtualization technology in cloud data centers, how to effectively place virtual machine （VM） is becoming a major issue for cloud providers. The existing virtual machine placement （VMP） solutions are mainly to optimize server resources. However, they pay little consideration on network resources optimization, and they do not concern the impact of the network topology and the current network traffic. A multi-resource constraints VMP scheme is proposed. Firstly, the authors attempt to reduce the total communication traffic in the data center network, which is abstracted as a quadratic assignment problem; and then aim at optimizing network maximum link utilization （MLU）. On the condition of slight variation of the total traffic, minimizing MLU can balance network traffic distribution and reduce network congestion hotspots, a classic combinatorial optimization problem as well as NP-hard problem. Ant colony optimization and 2-opt local search are combined to solve the problem. Simulation shows that MLU is decreased by 20%, and the number of hot links is decreased by 37%.

关键词： cloud computing data center network virtual machine placement traffic engineering network performance

Research on Computer network Can and performance Asalysis

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Transportation 1994年第1期11卷 1-6页

作者： Pan Qijing Yang Yonggao Wang Yu(Department of Computer Science,Southwest Jiaotong University, Chengdu 610031,China)

After analysing and discussing the goal and problems of computer networkdesign, the authors developed a computer network CAD with detaileddescriptions. Its architecture, functions and modules are given. Lastly a set o... 详细信息

关键词： computer network CAD network performance

Impacts of GPS Synchronization Loss on TD-SCDMA network performance

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2010年第2期8卷 43-47页

作者： Ji Shuping Liu Zhijian Dong Hui ZTE Corporation Shenzhen 518004 P. R. China

In Time Division Synchronous Code Division Multiple Access （TD-SCDMA） systems, the Global Positioning System （GPS） signal is often blocked or experiences interference. As a result, the GPS satellite cannot be found and synchronization cannot occur. Long out-of-sync periods can lead to timing differences between base stations, and if these differences are too large, they can affect the ability of Mobile Stations （MS） to search neighboring cells. This can also affect cell switchover, and cause Downlink Pilot Time Slot （DwPTS） to interfere with Uplink Pilot Time Slot （UpPTS）. All these manifest as handover failures, call dropouts during handover, and a declining rate of call completion. As a consequence, user experience within the network is diminished. Researchers have found that when GPS synchronization is lost for more than 4 chips, network quality deteriorates noticably. When the loss is more than 10 chips, the MS may fail to locate a neighboring cell. When the loss is below 16 chips, the interference of DwPTS with UpPTS is not obvious in the first and second circles of the GPS out-of-sync cells. Studies show that, to protect network performance, the TD-SCDMA system allows for up to 4 chips of timing difference in the case of GPS synchronization loss.

关键词： network performance TD-SCDMA Loss Code Division Multiple Access Global Positioning System differences network performance Time Slot Mobile Stations GPS Time Division base stations loss experiences found failures cell call quality search

performance improvement of licklider transmission protocol in complex deep space networks based on parameter optimization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第5期36卷 406-420页

作者： Guo YU Zhenxing DONG Yan ZHU Key Laboratory of Electronics and Information Technology for Space Systems National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified scenarios with one to two hops or multihop scenarios with a custody mechanism of the Bundle Protocol(BP).However,the research results are not applicable to communications in Complex Deep Space networks(CDSNs)without the custody mechanism of BP that are more suitable for deep space communications with LTP.In this paper,we propose a model of file delivery time for LTP in CDSNs.Based on the model,we propose a Parameter Optimization Design Algorithm for LTP(LTP-PODA)of configuring reasonable parameters for LTP.The results show that the accuracy of the proposed model is at least 6.47%higher than that of the previously established models based on simple scenarios,and the proposed model is more suitable for CDSNs.Moreover,the LTP parameters are optimized by the LTP-PODA algorithm to obtain an optimization plan.Configuring the optimization plan for LTP improves the protocol transmission performance by at least 18.77%compared with configuring the other parameter configuration plans.

关键词： Complex deep space networks File delivery time model Licklider Transmission Protocol(LTP) network performance network Protocols Parameter optimization performance improvement

Grey Hole Attack Detection and Prevention Methods in Wireless Sensor networks

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2022年第7期42卷 373-386页

作者： Gowdham Chinnaraju S.Nithyanandam Department of Computer Science and Engineering PRIST Deemed to be University613403India

Wireless Sensor networks(WSNs)gained wide attention in the past decade,thanks to its attractive features likeﬂexibility,monitoring capability,and scalability.It overcomes the crucial problems experienced in network man-agement and facilitates the development of diverse network architectures.The existence of dynamic and adaptive routing features facilitate the quick formation of such networks.Butﬂexible architecture also makes it highly vulnerable to dif-ferent sorts of attacks,for instance,Denial of Service(DoS).Grey Hole Attack(GHA)is the most crucial attack types since it creates a heavy impact upon the components of WSN and eventually degrades the performance of network.In cur-rent study,a simple attack detection,prevention and reduction approach is pro-posed.This is to secure the WSN from GHA and other such attacks by warning and blocking the malicious suspensions and by examining the storage table.Instead of blocking the entire host,the presented approach speciﬁcally elim-inates the malicious nodes.Further,in case of no malicious trafﬁc detection,the host gets unblocked.In current study,the researchers simulated the model under MATLAB environment and the outcomes showed an enhanced performance and increased utilization of Central Processing Unit(CPU)and packet delivery ratio.

关键词： Grey-Hole Attack WSN detection prevention reduction network performance

PCA-Based network Traffic Anomaly Detection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2016年第5期21卷 500-509页

作者： Meimei Ding Hui Tian School of Electronic and Information Engineering Beijing Jiaotong University Beijing 100044 China

The use of a Traffic Matrix（TM） to describe the characteristics of a global network has attracted significant interest in network performance research. Due to the high dimensionality and sparsity of network traffic, Principal Component Analysis（PCA） has been successfully applied to TM analysis. PCA is one of the most common methods used in analysis of high-dimensional objects. This paper shows how to apply PCA to TM analysis and anomaly detection. The experiment results demonstrate that the PCA-based method can detect anomalies for both single and multiple nodes with high accuracy and efficiency.

关键词： traffic matrix network performance principal component analysis anomaly detection

Optimal Coverage Multi-Path Scheduling Scheme with Multiple Mobile Sinks for WSNs

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第2期62卷 695-711页

作者： Jin Wang Yu Gao Chang Zhou R.Simon Sherratt Lei Wang School of Computer&Communication Engineering Changsha University of Science&TechnologyChangsha410114China School of Information Engineering Yangzhou UniversityYangzhou225009China School of Information Science and Engineering Fujian University of TechnologyFuzhou350000China Department of Biomedical Engineering University of ReadingBerkshire RG66AYUK School of Civil Engineering Changsha University of Science&TechnologyChangsha410114China

Wireless Sensor networks(WSNs)are usually formed with many tiny sensors which are randomly deployed within sensing field for target monitoring.These sensors can transmit their monitored data to the sink in a multi-hop communication manner.However,the‘hot spots’problem will be caused since nodes near sink will consume more energy during forwarding.Recently,mobile sink based technology provides an alternative solution for the long-distance communication and sensor nodes only need to use single hop communication to the mobile sink during data transmission.Even though it is difficult to consider many network metrics such as sensor position,residual energy and coverage rate etc.,it is still very important to schedule a reasonable moving trajectory for the mobile sink.In this paper,a novel trajectory scheduling method based on coverage rate for multiple mobile sinks(TSCR-M)is presented especially for large-scale WSNs.An improved particle swarm optimization(PSO)combined with mutation operator is introduced to search the parking positions with optimal coverage rate.Then the genetic algorithm(GA)is adopted to schedule the moving trajectory for multiple mobile sinks.Extensive simulations are performed to validate the performance of our proposed method.

关键词： WSNs mobile sink trajectory scheduling network performance

Multi-indicator Active Queue Management Method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2021年第8期38卷 251-263页

作者： Mosleh M.Abualhaj Abdelrahman H.Hussein Qasem M.Kharma Qusai Y.Shambour Faculty of Information Al-Ahliyya Amman UniversityAmman19328Jordan

A considerable number of applications are running over IP networks.This increased the contention on the network resource,which ultimately results in congestion.Active queue management(AQM)aims to reduce the serious consequences of network congestion in the router buffer and its negative effects on network performance.AQM methods implement different techniques in accordance with congestion indicators,such as queue length and average queue length.The performance of the network is evaluated using delay,loss,and throughput.The gap between congestion indicators and network performance measurements leads to the decline in network performance.In this study,delay and loss predictions are used as congestion indicators in a novel stochastic approach for AQM.The proposed method estimates the congestion in the router buffer and then uses the indicators to calculate the dropping probability,which is responsible for managing the router buffer.The experimental results,based on two sets of experiments,have shown that the proposed method outperformed the existing benchmark algorithms including RED,ERED and BLUE algorithms.For instance,in the first experiment,the proposed method resides in the third-place in terms of delay when compared to the benchmark algorithms.In addition,the proposed method outperformed the benchmark algorithms in terms of packet loss,packet dropping,and packet retransmission.Overall,the proposed method outperformed the benchmark algorithms because it preserves packet loss while maintaining reasonable queuing delay.

关键词： Congestion control network performance active queue management