Load Balancing for Parallel Forwarding

Workload distribution is critical to the performance of network processor based parallel forwarding systems. Scheduling schemes that operate at the packet level, e.g., round-robin, cannot preserve packet-ordering within individual TCP connections. Moreover, these schemes create duplicate information in processor caches and therefore are inefficient in resource utilization. Hashing operates at the flow level and is naturally able to maintain per-connection packet ordering; besides, it does not pollute caches. A pure hash-based system, however, cannot balance processor load in the face of highly skewed flow-size distributions in the Internet; usually, adaptive methods are needed. In this paper, based on measurements of Internet traffic, we examine the sources of load imbalance in hash-based scheduling schemes. We prove that under certain Zipf-like flow-size distributions, hashing alone is not able to balance workload. We introduce a new metric to quantify the effects of adaptive load balancing on overall forwarding performance. To achieve both load balancing and efficient system resource utilization, we propose a scheduling scheme that classifies Internet flows into two categories: the aggressive and the normal, and applies different scheduling policies to the two classes of flows. Compared with most state-of-the-art parallel forwarding schemes, our work exploits flow-level Internet traffic characteristics.     

一种高效的基于可复制资源的分布式负载均衡策略

为了克服传统负载均衡策略的缺陷,本文提出了一种高效的基于可复制资源的分布式负载均衡策略.在传统负载均衡策略基础上,本文提出了将节点的资源负载分为内部、外部和转发负载,并且分别进行处理的策略;同时给出了该策略的模型.此外,本文提出了负载的方向性概念,并将它应用于负载均衡策略中.最后,分析及仿真结果证明,该策略能够有效的均衡负载,减小内部通信量,同时能够有效的抑制系统负载抖动.     

Domain load balancing routing for multi-gateway wireless mesh networks

As Wireless Mesh Networks (WMNs) are typically used for Internet access, most traffic is routed through the gateways which connect WMN to the wired network. As a result, the gateways tend to get congested and balancing of the traffic load of gateways is critical. In this paper, we consider applications that require continuous provision of a certain bandwidth to a server located at the wired network. If a path that satisfies the bandwidth request cannot be found, the request will be rejected, so that load imbalance will result underutilization of the network capacity. We present a novel load balancing routing algorithm for maximizing the network utilization (i.e., accommodating service requests as many as possible) for multi-gateway WMNs. In the proposed scheme, a WMN is divided into domains. Each domain is served by one gateway, so that all traffic of a domain is served by the corresponding gateway. Our scheme determines routing to balance the traffic load among domains, and then performs load balancing routing within each domain. Simulation results show that in square grid topologies, our intra-domain routing achieves near optimal performance with about 70% less overhead than the existing schemes. Our inter-domain load balancing scheme outperforms the existing heuristics by up to 25% while achieving about 80% performance of the optimal solution.     

面向异构信号处理平台的负载均衡算法

针对当前异构信号处理平台中信号处理应用的调度算法优化目标单一且调度结果中处理器负载不均衡的问题，提出了一种基于蚁群优化算法的负载均衡算法。该算法结合蚁群优化算法的快速搜索能力和组合优化能力，以信号处理应用的调度长度和处理器负载均衡为优化目标，对初始信息素矩阵和蚂蚁的遍历顺序进行改进，提出调度长度启发因子和负载均衡启发因子对处理器选择公式进行改进，利用轮盘赌策略确定信号处理应用各子任务分配的处理器，完成信号处理应用的调度。仿真结果表明，该算法得到调度结果在调度长度和负载均衡方面均有改进，可以充分发挥各处理器性能，提高异构信号处理平台的整体效率。     

Load‐balancing channel assignment for dual‐band PCS networks

This paper investigates the channel assignment problem of dual‐band PCS systems where single‐band and dual‐band handsets co‐exist. Load‐balancing channel assignment schemes are proposed to improve the system performance. To balance the loads of both bands, the BSC selects a band to serve a call request of a dual‐band handset based on the loads of both bands. In addition, a channel re‐assignment scheme is used to further improve the system capacity. Analytic models and computer simulations have been developed to evaluate the performance of the load‐balancing schemes. The results indicate that both load‐balancing and channel re‐assignment techniques significantly increase the system capacity as the percentage of dual‐band handsets increases. Furthermore, the load‐balancing with channel re‐assignment scheme that combines both techniques achieves the best system performance even when the percentage of dual‐band handset is as low as 25%. In addition, we describe an approach to reduce the signal overhead of the load‐balancing schemes. Copyright © 2002 John Wiley & Sons, Ltd.     

Data Allocation and Dynamic Load Balancing for Distributed Video Storage Server

In this paper, a novel initial videos allocation scheme and a dynamic load balancing strategy are proposed for a distributed video storage server in order to increase the availability and reduce operation cost. The initial allocation scheme determines the allocation of video replicas on the servers to achieve static load balance and to obtain a configuration for efficient dynamic load adjustment. From the simulation results, the proposed load shifting algorithm can reduce up to 50% request fail rate if compared with the same initialization algorithm without load shifting. The proposed initial allocation with load shifting also reduces 25% to 60% request fail rate from the least load first initial allocation scheme with load shifting, 5% to 10% request fail rate and 5% to 25% the number of shifting steps from the DASD dancing method. Moreover, a prototype is implemented on Windows NT to examine the correctness and practicability of the proposed schemes.     

Multiprocessor DSP with multistage switching network for videocoding

A dynamic load balancing method is proposed that uses a multistage switching network to solve the problem of load concentration on certain processors for video coding in multiprocessor digital signal processors. (DSPs) This method balances the processing load by distributing the total load among the processor elements having smaller loads. The load distribution is performed by the multistage switching network, which transmits the load quantity information within the network. A scheduling method for a motion picture coding algorithm using multiprocessor DSPs is also proposed. This scheduling method takes full advantage of the multistage switching network functions when distributing the processing load and sorting the processed results. By using computer simulation, multiprocessor DSP performance with the proposed method is shown to be double that of a conventional multiprocessor DSP when an initially unbalanced load is allocated to the processors, as in picture coding for TV conferences     

基于mean-variance的服务集群负载均衡方法

大量并发请求任务进行分配时,负载调度机制是通过最小化响应时间及最大化节点利用率实现网络中节点的负载均衡,在基于遗传算法的负载均衡算法中,适应度函数设计对服务集群负载均衡效率产生重要的影响.对此提出了一种基于mean-variance的服务集群负载均衡方法对适应度函数进行优化,采用投资组合选择模型mean-variance进行最小化响应时间,以得到每个服务器资源利用率的权重,从而获得最优的分配组合,进而提高适应度函数的准确性和有效性.在不同服务环境下与其他模型进行比较,仿真结果表明,本文的负载均衡算法在节点利用率和响应时间方面使服务集群得到了更好的均衡.     

TD-SCDMA无线接入网自主负载均衡管理方法

基于自主管理技术和博弈理论提出一种自主负载均衡管理方法——博弈分流自主负载均衡法。通过理论分析证明了其中的关键算法可以收敛到局部最优解。通过仿真验证了新方法在均衡负载以及提升系统容量方面的性能优于现有方法,并能解决现有方法中基站交叠面积不受控和切换机制阻碍均衡行为的问题。     

ELAB:end-host-based congestion aware load balancing for data center network

A good load balance mechanism is the key to effectively use the network of the data center network.In current production data center,ECMP is the de facto load balancing scheme.However,it has two drawbacks.1) the load balance unit is too coarse-grained,2) it’s not congestion aware.To solve these problems,several fine-grained and congestion-aware load balancing works have emerged in recent years.These works either need to modify the switch hardware to collect congestion in various parts of the network in real time,and it is difficult to deploy; or only need to modify the end system,but the inaccurate sense of congestion cannot achieve a good load balancing effect.A novel edge-based load balancing scheme ELAB was proposed,which addresses above existing problems and improves the network performance up to 20%.     

异构分层无线网络中的混合动态流量均衡算法研究

结合信道借用和流量转移技术提出了一种混合动态流量均衡算法。使用该算法热点小区可以向紧凑模式中的同类型轻负载小区借用信道，同时还可以按一定条件将呼叫转移到与热点小区重叠覆盖的异构轻负载小区中，每个流量周期借用的信道数和转移的呼叫数将根据热点小区的剩余可用信道数和新呼叫到达率来计算。仿真结果表明，该流量均衡算法能够显著降低热点小区系统和整个异构系统的新呼叫阻塞概率、切换呼叫掉线率，而且整个异构系统的利用率也得到了相应提高。     

Performance analysis of load balancing in OFDMA cellular networks with inter‐cell relay

To balance and improve the resource utilization of the orthogonal frequency division multiple access (OFDMA) cellular networks, we switch parts of the edge users in overloaded cell to the adjacent light‐loaded cells by using the inter‐cell relay. The efficiency of traditional load balancing method based on the cell switching is low and in some cases, will occur the collision load problem. In this paper, we propose a new load balancing scheme based on inter‐cell relay in downlink OFDMA cellular networks. Besides, we put forward a new spectrum division scheme to reduce interference and improve spectrum efficiency. According to the formulas derived from the model we established, we can obtain the signal interference ratio and further to calculate the amount of remaining subcarrier and the throughput of the system. Finally, through numerical calculation and simulation, the result shows that the load balancing and spectrum division schemes can remit the resource stress of the overloaded cell and improve the spectrum utilization in adjacent cells.     

异构无线网络中基于业务转移和接入控制的混合负载均衡

 针对现有异构无线网络负载均衡方法未能综合考虑重载网络业务转移和新业务接入控制的问题,提出了一种混合负载均衡算法.该算法首先根据各小区负载水平和终端移动性,将重载小区的适量业务向重叠覆盖的轻载小区转移;其次通过资源预留和强占优先的接入控制策略,为不同优先级的新到业务提供有差别的服务.仿真结果表明,本文算法在保证系统资源利用率的同时,保障了实时与非实时业务的QoS,并相对于参考算法有效降低了系统阻塞率和业务切换概率.     

异构分层无线网络中基于逗留时间的动态流量均衡算法研究

为使异构分层无线网络能服务更多的移动用户,提出了一种基于逗留时间的动态流量均衡算法.该算法首先根据用户移动模型计算其在小区内的逗留时间,然后基于小区呼叫到达率和重叠覆盖小区的流量状态来确定一个周期内呼叫转移的数量,最后依据逗留时间门限值将重负载小区中满足条件的呼叫转移到轻负载的重叠覆盖小区中.为降低切换呼叫掉线率,还对异构网间的呼叫切换策略做了改进.仿真实验结果表明,本算法在新呼叫阻塞率和切换呼叫掉线率等性能指标上比传统方法有显著的提高.     

LTE网络多载波自动化智能均衡研究

网络负荷的增加,传统依靠人工调整负荷均衡已不能满足优化需求。自动化智能均衡方案通过穷举影响相邻两个小区覆盖性能的天馈、功率、互操作等类别参数,并进行归一化分析,自动输出负荷均衡调整方案。对无法通过覆盖均衡实现负荷均衡的小区,通过引入迭代算法,在优化边界范围内以固定步长自动输出负荷均衡调整建议,这有利于提高LTE网络容量、提高网络资源利用率、也有利于降低传输时延、降低人工和时间成本。     

基于干扰协调的主动负载均衡

为了解决负载均衡后分流的有实时业务需求的用户因受到严重的小区间干扰和因传统被动式方法固有的接入延迟所导致的用户体验下降的问题,本文提出了一种基于干扰协调的主动负载均衡算法。为了协调干扰,通过部分频率重用为小区边缘用户分配正交的资源;为了在满足用户数据率需求和均衡网络负载的前提下使系统总资源开销最小,通过预测用户的大尺度信道信息进行主动负载均衡。仿真结果表明,与现有的负载均衡方法相比,所提出的算法不仅提高了资源利用率,还降低了用户掉线概率。      

F－150程控交换机高负荷运行情况下的话务均衡

本文分析了Ｆ－１５０数字程控交换机高负荷运行情况下呼叫处理机（ＣＰＲ）和用户处理机（ＬＰＲ）负荷过载的原因和产生的后果，提出了通过均衡ＣＰＲ之间和ＬＰＲ之间的话务来消除处理机负荷过载，提高交换设备利用率和交换机接通率的方法和步骤。     

An Energy-Aware Hybrid Approach for Wireless Sensor Networks Using Re-clustering-Based Multi-hop Routing

In recent years, cloud computing provides a spectacular platform for numerous users with persistent and alternative varying requirements. In the cloud environment, security and service availability are the two most significant factors during the data encryption process. For providing optimal service availability, it is necessary to establish a load balancing technique that is capable of balancing the request from diverse nodes present in the cloud. This paper aims in establishing a dynamic load balancing technique using the APMG approach. Here in this paper, we integrated adaptive neuro-fuzzy interference system-polynomial neural network as well as memory-based grey wolf optimization algorithm for optimal load balancing. The memory-based grey wolf optimization algorithm is employed to enhance the precision of ANFIS-PNN and to maximize the locations of the membership functions respectively. Also, two significant factors namely the turnaround time and CPU utilization involved in optimal load balancing scheme are evaluated. Finally, the performance evaluation of the proposed MG-ANFIS based dynamic load balancing approach is compared with various other load balancing approaches to determine the system performances.

     

Two trellis coding schemes for large free distances

A trellis code encoded by using the encoder of a convolutional code C with a short constraint length followed by an additional processing unit is equivalent to a trellis code with a large constraint-length. In 1993, Hellstern proposed a trellis coding scheme for which the processing unit consists of a delay processor and a signal mapper. With Hellstern's scheme, trellis codes with large free distances can be constructed. In this paper, we propose two trellis coding schemes. For the first scheme, the processing unit is composed of multiple pairs of delay processors and signal mappers. For the second scheme, the processing unit is composed of a convolutional processor and a signal mapper, where a convolutional processor is a rate 1 convolutional code. The trellis code constructed from each of the proposed schemes can be suboptimally decoded by using the trellis of the convolutional code C with some feedback information. Either of the proposed schemes can produce a trellis code that has a larger bound on free distance and better error performance as compared to the trellis code constructed from Hellstern's scheme based on the same convolutional code C     

Load balancing in heterogenous distributed systems

In most distributed systems, the work generated at a node is processed there; little sharing of computational resources is provided. In such systems it is possible for some nodes to be heavily loaded while others are lightly loaded, resulting in poor overall system performance. The purpose of load balancing is to improve performance by redistributing the workload among the nodes.In this paper four load balancing techniques are studied by simulations. The study is limited to a class of techniques where the jobs are lined up in a generic queue and sent to a central job dispatcher which allocates the job to a particular processor based upon the following criteria: nondeterministic routing, response time, system time and throughout.We propose an algorithm that reduces the computational complexity of algorithms ensuring minimum system time.