检索结果-内蒙古大学图书馆

Fair service and dynamic round robin scheduling algorithm

ruan Jian Xue Bao/Journal of Software 2008年第7期19卷 1856-1864页

作者： Hu, Hong-Chao Yi, Peng Guo, Yun-Fei Li, Yu-Feng National Digital Switching System Engineering and Technological R and D Center Zhengzhou 450002 China Department of Information and Control Air Defense Command College Zhengzhou 450052 China

Scheduling policies are playing significant roles in guaranteeing the performance of core routing and switching devices. The limitations in complexities and extensibilities of current combined input and cross-point queueing switching fabric' scheduling policies are first analyzed. Then, based on this analysis, the principle for designing high extensible scheduling policies and the concept of virtual channel are proposed. Based on the principle and virtual channel, it comes up with a dynamic round robin scheduling algorithm-Fdr (fair service and dynamic round robin), which is simple, high efficiency and fair service. Fdr is based on round robin mechanism, whose complexity is only O(1). It allocates the scheduling share for each virtual channel according to its current states, thus, Fdr has good dynamic and real-time performance, and it can adapt to unbalanced traffic load network environment. Simulation results under SPES system show that Fdr exhibits good delay, throughput and anti-burst performance, which can be deployed in high performance routing and switching devices.

关键词： Scheduling

来源：评论

学校读者我要写书评

暂无评论

A novel high efficient scheduling algorithm for buffered crossbar switches

A novel high efficient scheduling algorithm for buffered cro...

引用

International Conference on Communications and Networking in China (CHINACOM)

作者： Peng Yi Shumin Chen Binqiang Wang National Digital Switch System Engineering & Technology R&D Center (NDSC) Zhengzhou China PLA Information Engineering University Zhengzhou China

With the development of ASIC technology, buffered-crossbar (CICQ) switch is becoming more and more attractive, and many scheduling algorithms have been proposed based on this architecture. However, the existing schemes are either still a little complicated in hardware implementation or low efficient in scheduling performance. In this paper, we propose a simple and high efficient scheduling algorithm called maximum urgency first (MUF). Since the MUF algorithm systematically evaluates the scheduling demands of both the input queues and the crosspoint queues in arbitrations of input scheduling, it not only can sufficiently make use of the output bandwidth, but also can efficiently control the increment of the input queue length. By compressing the queue length of the input queue and the crosspoint queue into the input urgency (IU) and the output urgency (OU), the implementation complexity of the MUF algorithm is largely decreased. Simulation results show that MUF can obtain better stability and delay performance than traditional scheduling schemes presented for CICQ switches.

关键词： Scheduling algorithm Switches delay Iterative algorithms Packet switching Throughput Traffic control round robin Impedance matching Scalability

来源：评论

学校读者我要写书评

暂无评论

A new distributed topology discovery technology for IPv6 networks

A new distributed topology discovery technology for IPv6 net...

引用

IEEE SoutheastCon 2007

作者： Liu, Zhenshan Wang, Qingxian Luo, Junyong National Digital Switching System Engineering and Technological R and D Center China

ISBN: (纸本)9781424410286

Most existed distributed topology discovery applications deploy multiple probing hosts throughout the network. Paths are then probed from the individual points and the data later is unified into a single topology graph. This approach relies on the ability to deploy probing hosts throughout the network, which in many cases is not possible. This paper presents MTAS(Multi Tunnel Access system), a system which deploys probing hosts in a single IPv4 subnet. Each probing host creates an IPv6 over IPv4 tunnel to reach an ISATAP (Intra-Site Automatic Tunnel Addressing Protocol) or 6to4 relay router which distributed in the world and provides service for public. In MTAS, ISATAP and 6to4 relay routers just work like probing springboards distributed in different location for IPv6 network topology discovery, so MTAS is a handy distributed application. To avoid retracing the same traceroute paths, MTAS system deploys a middle database to store the collected path. We also present some preliminary test results from probing CErNET2, the largest native IPv6 network in China. And the test results illustrate the effectiveness of MTAS.

关键词： probing springboard IPv6 over IPv4 distributed application

来源：评论

学校读者我要写书评

暂无评论

dESIGN ANd EVALUATION OF A PIPELINEd FOrWArdING ENGINE

引用

Journal of Electronics(China) 2007年第2期24卷 157-162页

作者： Li Yufeng Chen Yue Lan Julong National Digital Switching System Engineering ＆ Technological R ＆D Center Zhengzhou 450002 China

recent advances in broadband technology have caused forwarding engines to handle pack- ets with over 10 gigabit per second. In this paper, we present a high-speed forwarding pipeline which can finish all of the routing and forwarding tasks in the way of pipelining. We also establish the analysis model of the pipeline with which one can evaluate some key performance parameters of the forwarding engine such as forwarding rate and forwarding delay. We find that the pipeline is of good scalability and can forward unicast packets up to the speed of 40Gbit/s.

关键词： design Forwarding engine Pipeline Evaluate

来源：评论

学校读者我要写书评

暂无评论

An efficient and universal security architecture of implementing IPSec in broadband router

An efficient and universal security architecture of implemen...

引用

IFIP International Conference on Network and Parallel Computing

作者： Gu, Xiaozhuo Yang, Jianzu Yu, Jing Lan, Julong National Digital Switching System Engineering and Technological R and D Center Lanzhou City College China Information Engineering University China

ISBN: (纸本)9780769529431

With the demand of providing data security and integrity, IPSec is implemented in hardware of router to accelerate processing speed. After analyzing advantages and disadvantages of two traditional security architectures, Look-aside architecture and FlowThrough architecture, we propose parallel security processing architecture to achieve better time efficiency. This parallel security architecture adopts mechanism of processing IP packets and IPSec packets simultaneously, which optimizes the processing flow and improves the processing efficiency. The design of parallel security architecture is based on universal architecture of broadband, thus requires minimal change of hardware architecture when implemented in broadband router Testing results based on Sr1880s routers demonstrate that the proposed parallel security architecture is efficient and satisfies the security need of broadband networks.

关键词： routers

来源：评论

学校读者我要写书评

暂无评论

A Compensation Method of the Forward Power Control in Multi-service Hierarchical CdMA system

A Compensation Method of the Forward Power Control in Multi-...

引用

第三届IEEE无线通讯、网络技术暨移动计算国际会议

作者： Jiang Ji Kaizhi Huang Liang Jin National Digital Switching System Engineering & Technological R&D Center Zhengzhou China National Digital Switching System Engineering & Technological R&D Center Zhengzhou China

The paper presents a power control compensation method in the forward channel for the higher system capacity of the future Multi-Service hierarchical CdMA system. This method is mainly based on the confidence level and the estimation theory. The estimation has two steps, the channel fading estimation and the Mobile Station (MS) traffic amount estimation. The simulating results prove that it is better than the traditional power control methods by the great reduction of outage probability about 15％.

关键词： CdMA the multi-service hierarchical system power control compensation confidence level

来源：评论

学校读者我要写书评

暂无评论

Communication Optimization Algorithms based on Extend data Flow Graph

Communication Optimization Algorithms based on Extend Data F...

引用

ACIS International Conference on Software engineering, Artificial Intelligence, Networking, and Parallel/distributed Computing (SNPd)

作者： Xue-rong Gong rong-cai Zhao Lin-sheng Lu National Digital Switching System China National Digital Switching System Engineering &Technological R&D Center Zhengzhou CHINA Jiangnan Institute of Computing Technology China

reducing communication overhead is extremely important for parallelizing compiler to generate efficient codes for distributed memory machines. In this paper, a redundant parallel execution model (rPEM) is used as the model for target programs. The extend data flow graph is introduced, and optimization algorithms based on the data-flow analysis are discussed. The overhead of data flow analysis can be reduced by performing analysis on the extend dataflow graph. The analysis helps to reduce the redundant communication overhead. These optimization algorithms are able to perform inter-loop and inter-procedure analysis. Experimental results prove that these optimizations algorithms are effective in reducing both the number of communications and the communication volume.

关键词： Flow graphs data analysis Algorithm design and analysis doped fiber amplifiers data flow computing Performance analysis distributed computing Optimizing compilers Concurrent computing Communication system control

来源：评论

学校读者我要写书评

暂无评论

dESIGN ANd IMPLEMENTATION OF SINGLE-BUFFErEd rOUTErS

引用

Journal of Electronics(China) 2007年第4期24卷 470-476页

作者： Hu Ximing Qu Jing Wang Binqiang Wu Jiangxing National Digital Switching System Engineering ＆ Technological R＆D Center （ NDSC） No. 783 P.O. Box 1001 Zhengzhou 450002 China Institute of Telecommunication Engineering Air Force Engineering University No.1 Fenggao Road Xi＇ an 710077 China

A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group （HPNG） of Stanford University, along with two promising designs of SB routers： one of which was Parallel Shared Memory （PSM） router and the other was distributed Shared Memory （dSM） router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm （CMMA） which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued （VOIQ） router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and commu- nication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router （NdSC~ Sr1880-TTM series） are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.

关键词： Single-Buffered （SB） router distributed Shared Memory （dSM） Parallel Shared Memory （PSM） Virtual Output and Input Queued （VOIQ） NdSC Sr1880-T^TM router

来源：评论

学校读者我要写书评

暂无评论

Performance Analysis of 2-d-rAKE receivers with Imperfect Channel Estimation in Nakagami Fading Channels

Performance Analysis of 2-D-RAKE Receivers with Imperfect Ch...

引用

第三届IEEE无线通讯、网络技术暨移动计算国际会议

作者： Kaizhi Huang Jiangxing Wu National Digital Switching System Engineering & Technological R&D Center Zhengzhou 450002 China

In this paper, the closed-form expressions of signal-to-interference-plus-noise ratio (SINr) and the bit error rate (BEr) are derived for a maximal ratio combining (MrC) two-dimensional (2-d)-rAKE receiver with imperfect channel estimation in frequency-selective Nakagami fading channels. The impact of doppler frequency shift, the low pass filters (LPF) and the spatial-temporal diversity on the channel estimation and the performance of the receiver has been analyzed. Theoretical analysis and computer simulation results indicate that the performance degradation of 2-d-rAKE receivers due to imperfect channel estimation can be improved by using appropriate LPF taps and increasing the antenna numbers.

关键词： Channel estimation error (CEE) 2-d-rAKE receiver Bit error rate (BEr) doppler frequency shift Low pass filters

来源：评论

学校读者我要写书评

暂无评论

detecting and Solving Links Overlap to Make Structured P2P Network Topology-Aware

Detecting and Solving Links Overlap to Make Structured P2P N...

引用

International Conference on Communications and Networking in China (CHINACOM)

作者： Jing Yu XiaoZhuo Gu BinQiang Wang Technological R&D Center National Digital Switching System Engineering and Technological Research and Development Center Zhengzhou Henan China

Mismatching between overlay and physical network in structured P2P system leads to overlap of links crossed on backbone network, thus it brings link waste and congestion. A method used for detecting and resolving the link overlap problem is proposed in this paper. It introduces TTL as the measurement of distance, and adjusts the routing table of node according to redirect message achieved from TTL calculation and comparison. This method is protocol- independent and easy to be built on any structured P2P system. It avoids the inaccuracy problem that the time latency or IP information method contained. Through illustration, it is proved to indeed decrease the number of links crossed in routing procedure, thus resolves the waste of link bandwidth and useless flow over the backbone network brought by mismatching problem.

关键词： routing delay Network topology Spine Bandwidth switching systems systems engineering and theory research and development Electronic mail Stress

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：