一种新的P2P流媒体负载均衡路由算法

构建和维持一个高带宽路由结构是P2P流媒体中的一个重要问题。针对节点频繁地加入和退出覆盖会话的现状,本文设计了基于链路可用带宽的负载均衡路由算法LBR,利用已知的物理拓扑知识,在多条路由路径中选择一条对网络可用带宽影响最小的路由路径,得到轻负载的覆盖边。该算法能够动态维护高带宽的多播树,平衡覆盖会话中节点间的负载和链路间的流量。仿真实验表明,在动态环境下算法能够缓解路由上的拥塞问题,达到负载均衡的效果。     

一种SRIO网络负载均衡最短路径路由算法

在串行RapidIO传输过程中,路由选路算法是影响传输性能的重要因素之一。针对串行高速输入-输出(SRIO)网络深度优先搜索分配路径非最优问题,提出一种负载均衡最短路径路由算法。通过广度优先搜索对SRIO网络中的节点进行枚举并建立网络拓扑信息,以路由跳数定义路由的成本,根据改进Floyd-WarShall算法计算并保存交换节点间的K最短路径。给出预期负载的概念和链路上的路由路径数量来定义链路的负载,采用负载均衡算法从K最短路径中进行选路,建立SRIO网络最短路径约束的负载均衡路由。实验结果表明,与深度遍历路由算法、最小跳数算法相比,该算法在网络传输平均跳数、链路平均负载和链路负载均衡方面有更好的表现,能够有效提升SRIO路由网络的稳定性。     

一种基于动态负载均衡的路由算法

传统IGP仅基于最短路径算法来为数据流选择传输通路，对数据流的需求以及网络资源的动态变化未加以考虑，因此不具备均衡网络负载的能力。文中通过分析IGP的局限性，提出基于动态负载均衡的DLB-OSPF路由算法。该算法依据数据流的带宽需求和网络资源的使用状况来进行路由选择，并通过有效手段将数据流更合理地分配到能满足传输需求的链路上。经过示例分析表明，该算法不仅能减少网络拥塞，并且提高了网络资源利用率。     

基于负载均衡的虚拟网络映射算法研究

为保证虚拟网络请求成功映射,同时不会导致底层网络的部分负载过重,映射性能变差,需要对虚拟网络链路映射进行合理化负载均衡。本文中把虚拟链路带宽资源切片,利用增广子图路径方法选择底层路径,并且将不相交路径资源归一化,设计了基于负载均衡的虚拟网络映射算法。最后,通过仿真将负载均衡算法与路径割裂算法、K最短路径算法进行性能对比。仿真结果表明了负载均衡算法在虚拟网络映射的请求接受率、成本和收益指标方面优于其他两种算法。     

空基自组网中基于负载均衡的路由策略

针对空基网中节点负载失衡以及吞吐量低下的问题,提出基于负载均衡的优化路由协议。该协议在获得位置信息的前提下,预测出通信链路的有效时间,在满足数据的时延、带宽以及链路有效性等多约束条件下,以均衡节点负载为优化目标,使得网络节点都能合理承担数据传输任务。仿真结果表明,该路由协议能够保证网络节点合理分担传输任务,充分利用链路资源,从而提高网络的吞吐量。     

数据中心网络拓扑感知型拥塞控制算法

针对数据中心网络（DCN）的链路拥塞问题,提出了一种拓扑感知型拥塞控制算法（TACC）。首先,根据广义超立方体拓扑多维正交和单维全连接的结构特点,结合网络流的最大流最小割定理,提出了拓扑感知地选取分布流量请求的不相交路径策略;然后,根据带宽需求自适应选取不相交路径;最后,利用已选取路径的剩余带宽为权重动态调整每条路径的流量分配比例,从而达到缓解网络链路拥塞、均衡网络负载和减轻目的节点侧数据重组压力的目的。实验结果表明,与链路关键性路由算法（LCRA）、多路径健忘路由算法（MORA）、最小割多路径路由（MCMP）算法和免拥塞路由策略（CFRS）相比,TACC算法在均衡链路负载和优化算法部署时间方面有良好的表现。     

一种改进负载均衡的网络编码多播路由算法

已有研究证明,在多播网络中使用网络编码可以显著提高多播通信的性能。总结了网络编码多播理论的研究进展,同时对网络编码多播路由问题进行了研究与分析。考虑到影响链路负载和资源消耗的因素,提出了一种改进链路负载均衡的网络编码多播路由算法,优化了路径间链路的共享。通过使用常见的Waxman网络拓扑模型,产生随机网络拓扑。在这些拓扑中,分别针对传统IP多播路由、低速率网络下的网络编码多播路由以及提出的路由算法进行性能仿真。仿真结果表明,与其他两种路由算法相比,该算法在可达吞吐量、资源消耗和负载均衡等性能上均有很好的表现。     

一种基于多约束路径的QoS路由改进算法

针对MPLS网络,提出一种带宽时延约束路由改进算法,引入节点负荷率的限制,在路由时避开负载较重的链路,在保证用户业务带宽与时延约束的前提下,为一部分流量寻找一条相对较长但负载较轻的路径,以使得整个网络的流量分布更加均衡,从一定程度上可以减少网络拥塞。从仿真实验结果来看,改进后的算法在吞吐量、请求建立的成功率以及端到端时延等性能方面有比较好的表现。     

MIRA-N:一种改进的最小干扰路由算法

研究动态路由算法，提出了一种改进的最小干扰路由算法（MIRA-N）。该算法引入关键链路、次关键链路的定义，将算法分为预处理和在线路由两个过程，降低了算法复杂度影响。仿真结果表明该算法可使网络负载分布更为均衡、提高网络吞吐量，进一步改善最小干扰路由算法的性能。     

基于大流调度的软件定义数据中心网络负载均衡算法

传统负载均衡算法对数据中心网络中的大流进行调度时,会造成部分链路负载过重、网络整体负载不均衡等问题。将负载均衡问题转化为多商品流问题进行求解,结合软件定义网络集中控制的思想和数据中心网络的流量特征,提出一种基于大流调度的软件定义数据中心网络负载均衡算法。根据阈值将数据流划分为大流和小流,结合路径上大流分布度和可用负载度对大流进行重路由,以减小大流对网络负载均衡的影响。仿真实验表明,在流量大小分布不均衡的数据中心网络中,该算法与传统的等价多路径算法和基于全局最先匹配的动态流量调度算法相比,在平均对分带宽上获得了更大的提升,能够更好地实现数据中心网络的负载均衡。     

DORA: Efficient Routing for MPLS Traffic Engineering

This paper introduces DORA, a dynamic online routing algorithm for construction of bandwidth guaranteed paths in MPLS-enabled networks. The main objective of DORA is to place paths with reserved bandwidth evenly across the network in order to allow more future paths to be accepted into the network and to balance the traffic load. During path computation, the key operation in DORA is to avoid routing over links that (1) have high potential to be part of any other path, and (2) have low residual bandwidth available. Our simulation results based on unsuccessful path-setup ratio and successful path-reroutes upon link failure, show that DORA offers better performance than some sophisticated algorithms, while at the same time being less computationally expensive.     

Virtual network mapping algorithm in the cloud infrastructure

Network virtualization has received considerable attention recently because a Cloud Provider (CP) that is responsible for deploying a substrate network in the cloud infrastructure uses network virtualization to support multiple Virtual Network (VN) requests over the shared substrate network. However, mapping multiple VN requests with constraints on virtual nodes and virtual links into a shared substrate network presents a significant challenge, and is considered an NP-hard problem. In this paper, we propose a heuristic mapping algorithm that handles online VN requests. The node mapping algorithm selects a substrate node for mapping that satisfies both a virtual node's resource requirement and its amount of requested bandwidth. The link mapping algorithm either maps a virtual link to the shortest substrate path that satisfies the requested bandwidth of the virtual link or uses the cut-shortest path approach to map a virtual link to multiple substrate paths that satisfy the requested bandwidth of the virtual link. The path migration algorithm migrates virtual links to different substrate paths to maximize the number of accepted VN requests in a substrate network. Simulation results show that the proposed heuristic mapping algorithm uses resources more efficiently, produces more revenue, and has better performance than existing mapping approaches.     

一种基于SDN和MPTCP的多径并行传输技术

本文提出了根据网络信息状态通过SDN控制器来控制MPTCP流量以提高并行传输速率。利用本文所提出的最宽不相交选路算法,为每个MPTCP连接选择一组可用带宽最宽且链路差距较小的路径集。然后使用可用路径容量的比例作为流量分配到该路径上的概率,进一步减小子流的带宽差距。最后,通过搭建Floodlight仿真实验平台,证明本方案能够避免MPTCP的不同子流经过同一路径,并有效的利用路径提升并行传输效率。     

Analysis of bandwidth allocation on end-to-end QoS networks under budget control

This paper considers the problem of bandwidth allocation on communication networks with multiple classes of traffic, where bandwidth is determined under the budget constraint. Due to the limited budget, there is a risk that the network service providers can not assert a 100% guaranteed availability for the stochastic traffic demand at all times. We derive the blocking probabilities of connections as a function of bandwidth, traffic demand and the available number of virtual paths based on the Erlang loss formula for all service classes. A revenue/profit function is studied through the monotonicity and convexity of the blocking probability and expected path occupancy. We present the optimality conditions and develop a solution algorithm for optimal bandwidth of revenue management schemes. The sensitivity analysis and three economic elasticity notions are also proposed to investigate the marginal revenue for a given traffic class by changing bandwidth, traffic demand and the number of virtual paths, respectively. By analysis of those monotone and convex properties, it significantly facilitates the operational process in the efficient design and provision of a core network under the budget constraint.     

面向SDN数据中心网络最大概率路径流量调度算法

随着数据中心网络规模的迅速增长,网络带宽利用率低下导致的网络拥塞问题日益突出,通过负载均衡提高数据中心网络链路带宽利用率和吞吐量成为了研究热点.如何结合流量特征、链路状态和应用需求进行流量的合理调度,是实现网络链路负载均衡的关键.针对数据中心突发性强、带宽占用率高的大象流调度问题,提出一种面向SDN数据中心网络最大概率路径流量调度算法,算法首先计算出满足待调度流带宽需求所有路径,然后计算流带宽与路径最小链路带宽之间的带宽比,结合所有路径的带宽比为每一条路径计算路径概率,最后利用概率机制选择路径.算法不仅考虑了流带宽需求和链路带宽使用情况,而且全局地考虑了流调度和链路带宽碎片问题.实验结果表明,最大概率路径调度算法能够有效地缓解网络拥塞,提高带宽利用率和吞吐量,减少网络延迟,从而提高数据中心的整体网络性能和服务质量.     

SDN多控制器部署及流量均衡研究

随着网络的发展，单一的控制器已经无法满足大量交换机的控制需要，需要使用多个控制器。利用改进的k-means++算法对网络拓扑图进行划分，将网络拓扑抽象为无向图，将网络中多控制器部署问题抽象为无向图的最短路径问题。以边的权重来划分图，权重由链路带宽和传输时延加权得出，比较2种方式的负载均衡度和成本得出多控制器部署策略。随后通过对网络中的多条路径采取流量均衡策略，使数据合理地分布在不同的路径上，使网络流量分配更平均，网络性能更高。实验表明，数据包在有多条路径可选择的情况下，可以合理选择传送路径，使网络中各个路径的负载更均衡。     

Using Shared Risk Link Groups to enhance backup path computation

To cope quickly with all types of failure risks (link, node and Shared Risk Link Group (SRLG)), each router detecting a failure on an outgoing interface activates locally all the backup paths protecting the primary paths which traverse the failed interface. With the observation that upon a SRLG failure, some active backup paths are inoperative and do not really participate to the recovery (since they do not receive any traffic flow), we propose a new algorithm (SRLG structure exploitation algorithm or SSEA) exploiting the SRLG structures to enhance the admission control and improve the protection rate.With our algorithm, more flexibility is provided for the backup path selection since a backup path which protects against the failure of a link belonging to a SRLG does not systematically bypass all the links of that SRLG. Moreover, our algorithm permits to save more bandwidth because it does not allocate the bandwidth for the inoperative backup paths even if they are activated.Simulations show that our algorithm SSEA decreases the ratio of rejected backup paths and, it reduces in distributed environments the average number of messages sent to manage the bandwidth information necessary for the backup path computation.     

多信道无线网状网带宽有效的路由机制设计

针对基于IEEE 802.11标准的多信道无线网状网中采用接纳控制方案,设计出一种分布式的低干扰且带宽保证的最短路径路由协议;该协议通过分布式免干扰的链路调度机制,并根据带宽要求为链路分配相应时槽数,以实现带宽保证的链路流。NS-2模拟实验结果显示,该协议能为通信链路提供有效的带宽保证,对于有带宽保证要求的业务,可实现较高的通信连接成功概率,具有良好的性能。     

一种最小化最大带宽利用率的TE路由算法

随着网络中流量的迅速增长，流量工程对于减小拥塞、提高网络资源的使用效率、满足业务的QoS要求，正在起着越来越重要的作用．提出了一种对Dijkstra算法进行改进的最小化最大带宽利用率TE路由算法．该算法在搜寻路径的过程中，将原来Dijkstra算法中的以路径代价最小为目标，更改为以最小化最大带宽利用率为目标．仿真证明，算法在一定程度上达到了均衡负载分布的作用．     

Replicated Server Placement with QoS Constraints

The network planning problem of placing replicated servers with QoS constraints is considered. Each server site may consist of multiple server types with varying capacities and each site can be placed in any location among those belonging to a given set. Each client can be served by more than one location as long as the round-trip delay of data requests satisfies predetermined upper bounds. Our main focus is to minimize the cost of using the servers and utilizing the link bandwidth, while serving requests according to their delay constraint. This is an NP-hard problem. A pseudopolynomial and a polynomial algorithm that provide guaranteed approximation factors with respect to the optimal for the problem at hand are presented.