On the use of the genetic programming for balanced load distribution in software-defined networks

As a new networking paradigm, Software-Defined Networking (SDN)enables us to cope with the limitations of traditional networks. SDN uses a controller that has a global view of the network and switch devices which act as packet forwarding hardware, known as “OpenFlow switches”. Since load balancing service is essential to distribute workload across servers in data centers, we propose an effective load balancing scheme in SDN, using a genetic programming approach, called Genetic Programming based Load Balancing (GPLB). We formulate the problem to find a path: 1) with the best bottleneck switch which has the lowest capacity within bottleneck switches of each path, 2) with the shortest path, and 3) requiring the less possible operations. For the purpose of choosing the real-time least loaded path, GPLB immediately calculates the integrated load of paths based on the information that receives from the SDN controller. Hence, in this design, the controller sends the load information of each path to the load balancing algorithm periodically and then the load balancing algorithm returns a least loaded path to the controller. In this paper, we use the Mininet emulator and the OpenDaylight controller to evaluate the effectiveness of the GPLB. The simulative study of the GPLB shows that there is a big improvement in performance metrics and the latency and the jitter are minimized. The GPLB also has the maximum throughput in comparison with related works and has performed better in the heavy traffic situation. The results show that our model stands smartly while not increasing further overhead.     

Load Balancing Technique for Congestion Control Multipath Routing Protocol in MANETs

A mobile ad hoc network (MANET) is a collection of wireless mobile nodes that can communicate without a central controller or fixed infrastructure. Due to node mobility, designing a routing protocol to provide an efficient and suitable method to route the data with less energy consumption, packet drop and to prolong the network lifetime has become a challenging issue in MANETs. In MANETs, reducing energy consumption and packet loss involves congestion control and load balancing techniques. Thus, this paper introduces an efficient routing technique called the multipath load balancing technique for congestion control (MLBCC) in MANETs to efficiently balance the load among multiple paths by reducing the congestion. MLBCC introduces a congestion control mechanism and a load balancing mechanism during the data transmission process. The congestion control mechanism detects the congestion by using an arrival rate and an outgoing rate at a particular time interval T. The load balancing mechanism selects a gateway node by using the link cost and the path cost to efficiently distribute the load by selecting the most desirable paths. For an efficient flow of distribution, a node availability degree standard deviation parameter is introduced. Simulation results of MLBCC show the performance improvements in terms of the control overhead, packet delivery ratio, average delay and packet drop ratio in comparison with Fibonacci sequence multipath load balancing, stable backbone-based multipath routing protocol and ad hoc on demand multipath distance vector routing. In addition, the results show that MLBCC efficiently balances the load of the nodes in the network.

     

一种基于游标的多径流量分割算法

 多径传输使用多条连接源节点和目的节点的路径进行传输,在提高资源利用率的同时会引起包乱序问题,并且存在路径之间的负载均衡问题.本文提出了一种基于游标的流量分割算法,游标是当前路径传输延迟与相邻包到达源节点的时间差之间的差值,它作为选取路径的延时基线来保证包到达的有序性,游标会随着路径不同或相邻包到达源节点的时间差不同而动态地滑动,通过动态滑动游标使得尽可能多的路径可用来传输当前包,从而很好地实现负载均衡.仿真结果表明,与已有的保证包有序的算法相比,本算法使负载更加均衡.     

Queue‐based multiple path load balancing routing protocol for MANETs

Congestion in the network is the main cause for packet drop and increased end‐to‐end transmission delay of packet between source and destination nodes. Congestion occurs because of the simultaneous contention for network resources. It is very important to efficiently utilize the available resources so that a load can be distributed efficiently throughout the network. Otherwise, the resources of heavily loaded nodes may be depleted very soon, which ultimately affects network performances. In this paper, we have proposed a new routing protocol named queue‐based multiple path load balancing routing protocol. This protocol discovers several node‐disjoint paths from source to destination nodes. It also finds minimum queue length with respect to individual paths, sorts the node‐disjoint paths based on queue length, and distributes the packets through these paths based on the minimum queue length. Simulation results show that the proposed routing protocol distributes the load efficiently and achieves better network performances in terms of packet delivery ratio, end‐to‐end delay, and routing overhead. Copyright © 2016 John Wiley & Sons, Ltd.     

无线多媒体传感器网络中一种改进路由算法

随着网络负载增加,经典的TPGF( Two-Phase geographic Greedy Forwarding)算法难以找到节点分离路径,会导致网络吞吐量、投递率以及端到端时延性能下降。此外,当网络拓扑变动不大时, TPGF中每条路径所包含节点要消耗比其他节点更多的能量,会导致其过快死亡,从而影响网络性能。为此,将联合网络编码技术引入 TPGF,提出一种编码与能量感知的 TPGF 路由算法( NE-TPGF)。该算法综合考虑节点的地理位置、编码机会、剩余能量等因素,同时利用联合网络编码技术进一步扩展编码结构,充分利用网络编码优势来建立相对最优的传输路径。仿真结果表明, NE-TPGF能够增加编码机会,提高网络吞吐量和投递率,降低端到端时延,并且还有利于减少和平衡节点的能量消耗。     

Ad hoc网络中不相关多路由源端寻路算法

路由方案是Ad hoc网络中一个热点研究领域。其中,按需路由算法由于其有效性在带宽受限的Ad hoc网络中得到比较大的发展。然而大部分的按需路由算法,建立并只使用单条路由,当前使用的路径的链路断开时,路由算法必须执行一个路由修复过程。提出了不相关多路由源端路由算法（DMSR）,建立并利用多条最大不相关路由。算法中,中间节点等待一段时间以得到多个路由请求包（RREQ）,然后在这个RREQ中,选择相关性最小的多路径,并将这些信息写入一个RREQ中,并将它广播出去。从仿真结果可以看出本文的算法提高了数据包的正确传输率和业务均衡性。     

Routing Strategies to Minimize Packet Loss in an Optical Packet Switched Network with Recirculating FDL Buffers

The major goal of optical packet switching (OPS) is to match switching technology to the huge capacities provided by (D)WDM. We study optical packet switches with recirculating fiber delay line (FDL) buffers. Through simulation, we have assessed the logical performance of a single optical packet router (OPR), focusing on packet loss rate (PLR). By verifying that our scheduling algorithm does not alter the traffic profile characteristics from in- to output, we illustrate how the single node results can be used to assess network-wide performance. We use the capability of assessing end-to-end PLRs to develop network-wide routing algorithms designed to minimize the maximal PLR occurring in the network. In case studies on pan-European networks, we first compare two algorithm variants and thereafter we compare the PLR-based routing algorithm with both load balancing and shortest path routing. While load balancing achieves PLRs that are multiple orders of magnitude lower than shortest path routing, the PLR-based algorithm can reach PLRs up to two orders of magnitude better. The improvement in PLR comes at the price of only a small increase in used bandwidth (a few percent). Subsequently we show that the discussed PLR-based routing algorithm can be easily extended to multiple priorities. By introducing multiple priorities we can keep the loss rates for high priority traffic very low. However, it may lead to an increase of the obtained minimal max-PLR value for low priority traffic. But as we prove this increase to be limited, the cost of introducing multiple priorities is small.     

Path diversification for future internet end-to-end resilience and survivability

Path Diversification is a new mechanism that can be used to select multiple paths between a given ingress and egress node pair using a quantified diversity measure to achieve maximum flow reliability. The path diversification mechanism is targeted at the end-to-end layer, but can be applied at any level for which a path discovery service is available. Path diversification also takes into account service requirements for low-latency or maximal reliability in selecting appropriate paths. Using this mechanism will allow future internetworking architectures to exploit naturally rich physical topologies to a far greater extent than is possible with shortest-path routing or equal-cost load balancing. We describe the path diversity metric and its application at various aggregation levels, and apply the path diversification process to 13 real-world network graphs as well as 4 synthetic topologies to asses the gain in flow reliability. Based on the analysis of flow reliability across a range of networks, we then extend our path diversity metric to create a composite compensated total graph diversity metric that is representative of a particular topology’s survivability with respect to distributed simultaneous link and node failures. We tune the accuracy of this metric having simulated the performance of each topology under a range of failure severities, and present the results. The topologies used are from national-scale backbone networks with a variety of characteristics, which we characterize using standard graph-theoretic metrics. The end result is a compensated total graph diversity metric that accurately predicts the survivability of a given network topology.     

A Neural Network Method for Traffic Dispersion

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Multipath routing in mobile ad hoc network with probabilistic splitting of traffic

Multipath routing is a burning issue in mobile ad hoc network due to its various advantages over single path routing. Some of these advantages are load balancing, bandwidth aggregation, and fault tolerance. Multipath routing means multiple paths exist between source and destination pair. Many works discussed in section 2 addressed queuing delays, but none of them suggested queuing delay for multiple path deliveries of data in mobile ad hoc network context. In this paper, we have designed a mathematical model to compute delay and throughput for multipath. Our model follow the network of M/M/1 queues, and we have applied Burke’s theorem to calculate the queuing delay of the packet in mobile network scenario. This model can be used to estimate delay and throughput of an individual path. Further, through the analysis the best path for data delivery out of available multiple paths as well as the multipath path can be used simultaneously for data delivery to the destination. Simulation result shows that splitted traffic multiple paths outperform splitted traffic. Therefore, our model is useful for design and analysis of ad hoc network. The simulation work has been carried out in Qualnet simulator.     

业务分离的一种神经网络方法

在分组交换网络中,源目节点对（ｓｏｕｒｃｅ－ｄｅｓｔｉｎａｔｉｏｎ ｐａｉｒ,下称ＳＤ对）之间的业务常常需要在多条路径上并行传输。本文研究如何将业务流有效地分布于一组路径上,以使网络具有最小的分组平均时延。由于这个问题在很多情况下需要实时处理,因此我们提出了一种神经网络方法来加以解决,在一个典型网络上的试验表明,我们的方法获得的结果优于前人用各种严格的数学分析方法得到的好的结果。     

Automated adaptive on-line Multi-Layer Traffic Engineering through “tailoring” wavelength-paths in the Fragment Graph

In Multi-Layer networks, where more than one layer is switched, i.e., connections are set up using not only the upper, e.g., IP layer but the underlying wavelength layer as well leads often to suboptimal performance due to long wavelength paths, that do not allow routing the traffic along the shortest path. The role of MLTE (Multi-Layer Traffic Engineering) is to cut (fragment) these long wavelength-paths into parts (fragments) that allow better routing at the upper layer, or to concatenate (defragment) two or more fragments into longer paths when the network load is low and therefore fewer hops are preferred.In this paper we present a new model, the Fragment Graph (FG) and an algorithm for this model that supports Fragmentation and De-Fragmentation of wavelength paths making the network always instantly adapt to changing traffic conditions. We introduce the notion of shadow links to model “λ-path tailoring”. We implicitly assume that the wavelength paths carry such, e.g., IP traffic that can be interrupted for a few milliseconds and that even allows minor packet reordering.To show the superior performance of our approach in various network and traffic conditions we have carried out an intensive simulation study where we compare blocking ratios and path lengths and we analyze the dynamic behavior and fairness of the proposed and of reference methods.     

Multipath routing in the presence of frequent topological changes

In this article we propose a framework for multipath routing in mobile ad hoc networks and provide its analytical evaluation. The instability of the topology (e.g., failure of links) in these types of networks, due to nodal mobility and changes in wireless propagation conditions, makes transmission of time-sensitive information a challenging problem. To combat this inherent unreliability of these networks, we propose a routing scheme that uses multiple paths simultaneously by splitting the information among the multitude of paths, to increase the probability that the essential portion of the information is received at the destination without incurring excessive delay. Our scheme works by adding some overhead to each packet, which is calculated as a linear function of the original packet bits. The resulting packet (information and overhead) is fragmented into smaller blocks and distributed over the available paths. Our goal is, given the failure probabilities of the paths, to find the optimal way to fragment and then distribute the blocks to the paths so that the probability of reconstructing the original information at the destination is maximized. Our algorithm has low time complexity, which is crucial since the path failure characteristics vary with time and the optimal block distribution has to be recalculated in real time     

基于蚂蚁算法的WDM网络动态逻辑拓扑重配置

本文提出了基于蚂蚁选路的WDM网络动态逻辑拓扑重配置算法。利用蚁群选路的天然特性,在作了适当的假设后,我们推导出基于动态负载平衡的蚂蚁选路概率表达式,一方面使所选路由尽量短,另一方面尽量保持负载分布的平衡性。当业务动态变化时,网络节点根据算法的收敛结果做出相应调整。仿真结果表明,算法对动态业务方式的逻辑拓扑重配置是很有效的。     

Power Efficient Video Multipath Transmission over Wireless Multimedia Sensor Networks

This paper proposes a power efficient multipath video packet scheduling scheme for minimum video distortion transmission (optimised Video QoS) over wireless multimedia sensor networks. The transmission of video packets over multiple paths in a wireless sensor network improves the aggregate data rate of the network and minimizes the traffic load handled by each node. However, due to the lossy behavior of the wireless channel the aggregate transmission rate cannot always support the requested video source data rate. In such cases a packet scheduling algorithm is applied that can selectively drop combinations of video packets prior to transmission to adapt the source requirements to the channel capacity. The scheduling algorithm selects the less important video packets to drop using a recursive distortion prediction model. This model predicts accurately the resulting video distortion in case of isolated errors, burst of errors and errors separated by a lag. Two scheduling algorithms are proposed in this paper. The Baseline scheme is a simplified scheduler that can only decide upon which packet can be dropped prior to transmission based on the packet’s impact on the video distortion. This algorithm is compared against the Power aware packet scheduling that is an extension of the Baseline capable of estimating the power that will be consumed by each node in every available path depending on its traffic load, during the transmission. The proposed Power aware packet scheduling is able to identify the available paths connecting the video source to the receiver and schedule the packet transmission among the selected paths according to the perceived video QoS (Peak Signal to Noise Ratio—PSNR) and the energy efficiency of the participating wireless video sensor nodes, by dropping packets if necessary based on the distortion prediction model. The simulation results indicate that the proposed Power aware video packet scheduling can achieve energy efficiency in the wireless multimedia sensor network by minimizing the power dissipation across all nodes, while the perceived video quality is kept to very high levels even at extreme network conditions (many sensor nodes dropped due to power consumption and high background noise in the channel).     

一种基于信道阻力的Ad hoc网络多路径路由算法

该文提出了一种基于信道阻力的Ad hoc网络多路径动态源路由算法。算法中定义了信道阻力的概念,并以信道阻力为依据来进行多条路径的流量分配,由于信道阻力计算中综合考虑了链路质量的各个度量参数,因此能够根据各条路径的传输能力合理分配数据流量。NS2环境下的仿真表明,新算法能够有效地平衡网络负载,提高网络的吞吐量。     

An adaptive‐aware energy and queue improvement of AOMDV

Because the node energy and network resources in the wireless sensor network (WSN) are very finite, it is necessary to distribute data traffic reasonably and achieve network load balancing. Ad hoc on‐demand multipath distance vector (AOMDV) is a widely used routing protocol in WSN, but it has some deficiencies: establishes the route by only using hop counts as the routing criterion without considering other factors such as energy consumption and network load; forwards route request in fixed delay resulting in building the nonoptimal path; and cannot update the path status after built paths. For the deficiency of AOMDV, this paper proposes a multipath routing protocol adaptive energy and queue AOMDV (AEQAOMDV) based on adaptively sensing node residual energy and buffer queue length. When sending a routing request, the forwarding delay of the routing request is adaptively adjusted by both the residual energy and the queue length of the intermediate node; when establishing routes, a fitness is defined as a routing criterion according to the link energy and the queue load, predicting the available duration of the node based on the energy consumption rate and adjusting the weight of the routing criterion by the available duration of the node; after the routes are established, the path information status are updated via periodically broadcasting Hello that carries the path information with the minimum fitness, making the source node update the path information periodically. By using NS‐2, simulations demonstrate that compared with AOMDV, AEQAOMDV has obvious improvements in increasing packet delivery ratio, reducing network routing overhead, reducing route discovery frequency, and decreasing the network delay. And AEQAOMDV is more suitable for WSN.     

Hybrid routing and load balancing protocol for wireless sensor network

In wireless sensor network, when the nodes are mobile, the network structure keeps on changing dynamically, that is, new nodes enter the network and old members exit the network. As a result, the path from one node to the other varies from time to time. In addition, if the load on a particular part of the network is high, then the nodes will not be capable of transmitting the data. Thus, data delivery at the destination will be unsuccessful. Moreover, the part of the network involved in transmitting the data should not be overloaded. To overcome these issues, a hybrid routing protocol and load balancing technique is discussed in this paper for the mobile data collectors in which the path from source to destination is ensured before data transmission. The hybrid routing protocol that combines the reactive and proactive approach is used to enhance gradient based routing protocol for low power and lossy networks. This protocol can efficiently handle the movement of multiple sinks. Finally, load balancing is applied over the multiple mobile elements to balance the load of sensor nodes. Simulation results show that this protocol can increase the packet delivery ratio and residual energy with reduced delay and packet drop.     

网络负载均衡的控制理论及实践战略

网络负载均衡技术NLB（Network Load Balancing）采用完全分配算法来为集群中的服务器分配进入的访问流量,当集群中的某台服务器失效时,NLB会自动转发数据到其他可用的服务器上。负载均衡由多台服务器以对称的方式组成一个服务器集合,每台服务器都具有等价的地位,都可以单独对外提供服务而无须其他服务器的辅助。通过某种负载分担技术,将外部发送来的请求均匀分配到对称结构中的某一台服务器上,而接收到请求的服务器独立地回应客户的请求。均衡负载能够平均分配客户请求到服务器列阵,籍此提供快速获取重要数据,解决大量并发访问服务问题。     

Threshold-Based Load Balancing for Multiple Home Agents in Mobile IP Networks

Mobile IP is an extension of the IP protocol, designed to provide seamless connectivity to mobile nodes roaming over the Internet. Under certain conditions of traffic, such as in Mobile IP networks supporting multimedia applications, overhead can cause significant delays at the mobility agents, i.e. foreign and home agents. Some multiple home agents protocol extensions have been proposed to avoid potential bottlenecks in single home agents configurations. Due to the highly unpredictable nature of the IP data traffic, efficient load balancing applied in such schemes is crucial to the overall performance improvement. In this paper, we propose a novel threshold-based dynamic load balancing policy that uses a realistic data-sharing model operational at each home agent. A discrete event computer simulator is developed to study the system performance with the proposed load balancing policy. We also introduce two new policy tuning parameters, the number of information queue slices and the retry latency, by which we control the load balancing benefit. Due to the relatively large number of simulation parameters, results are presented for typical configuration scenarios. In general, in all the results obtained, our threshold-based load balancing policy provides a significant performance improvement. The proposed architecture efficiently uses parallel processing for handling the overhead generated by the load balancing, which results in minimal performance degradation.