一种软件定义网络中基于蚁群算法的一致性路由策略

软件定义网络通过对交换机下发流表项实现数据平面的更新,但流表项的安装具有时延,可能导致部分数据分组被错误地处理或丢弃。对此,提出一种基于蚁群算法的一致性路由策略,在路由参数中加入不一致时延,并通过控制器对流表的下发顺序做出调整,避免了在数据分组传输过程中,交换机控制逻辑的不一致。实验结果表明,与最短路径算法相比,出现不一致问题时,该策略所选路径的实际时延小于最短路径算法的时延,数据分组丢失率、错误转发的概率明显降低。     

软件定义卫星光网络蚁群优化波长路由技术

针对卫星光网络中网络拓扑动态时变和业务类型多样化的问题,研究了在软件定义网络架构下保障服务质量的路由技术,提出了一种基于多业务的卫星光网络蚁群优化波长路由算法。通过改进蚁群算法的启发函数,将波长空闲率、时延、时延抖动、丢包率作为蚂蚁选路的重要依据,为业务选择了满足多种服务质量的最优路径;采用分组波长分配方法对不同等级的业务进行了区分服务,为不同业务分配了不同的波长集。仿真结果表明:与CL-ACRWA算法和Dijkstra算法相比,降低了卫星光网络的平均时延、平均时延抖动、平均丢包率,提高了波长利用率,同时也降低了高优先级业务的网络拥塞概率。     

安全保障：无线Mesh网络中支持QoS的DSR路由协议的改进与实现

随着无线Mesh网络传输多媒体业务需求的增加,要求网络支持服务质量（QoS）,本文基于DSR协议设计了一个支持QoS的路由协议算法QDSR（QoS-DSR）。该算法保证了数据流的带宽、时延的QoS需求,根据路径跳数和节点拥塞情况定义路由代价函数,选择最优路径。仿真结果表明,与DSR相比,QDSR提高了网络吞吐量,降低了平均端到端延时,提高了网络利用率,更好地满足业务的QoS需求,并且具有更强的适用性和可扩展性。     

Ad hoc网络中一种新的路由选择算法

提出了一种基于平均分组时延与分组能量消耗乘积最小的路由路径选择算法。该算法根据路径的平均分组时延和分组能量消耗情况来进行路由路径选择。仿真表明，该算法可以动态调整网络路由路径，使所选路径的平均分组时延与分组能量消耗乘积达到最小。     

面向多优先级的绿色路由算法的研究北大核心CSCD

针对IP over WDM网络,提出一种面向多优先级的绿色路由算法,对网络传送的业务进行QoS等级划分。对不同优先级的业务,制定不同的路由选择标准,综合考虑业务的QoS要求和网络功耗优化问题。仿真结果表明,与普通绿色路由算法相比,该算法在低负载时可以减少约40%的时延和52%的物理跳数,同时节能效果也优于普通绿色路由算法。     

面向多优先级的绿色路由算法的研究

针对IP over WDM网络,提出一种面向多优先级的绿色路由算法,对网络传送的业务进行QoS等级划分。对不同优先级的业务,制定不同的路由选择标准,综合考虑业务的QoS要求和网络功耗优化问题。仿真结果表明,与普通绿色路由算法相比,该算法在低负载时可以减少约40%的时延和52%的物理跳数,同时节能效果也优于普通绿色路由算法。     

一种基于蚁群系统原理的QoS单播路由算法

蚁群算法是一种基于蚁群系统原理的、具有自组织能力的、新型的启发式优化算法。为了研究QoS路由问题,本文利用蚁群算法能寻找最短路径这一特性,提出了一种基于蚁群系统原理、用于解决带宽和时延约束问题的QoS单播路由算法。仿真结果表明了该算法的有效性、自适应性、鲁棒性和可扩展性。     

基于蚁群优化算法的多QoS选播路由算法研究

提出一种基于蚁群优化算法的多QoS选播路由算法.算法设计了合理的路径评价方法,从平衡网络负载的角度出发,寻找适当的选播路由路径.通过对迭代最优解路径上的信息素的调整和算法重启的策略,算法有效地避免了陷入局部最优的缺陷,扩大了算法的搜索范围.实验结果表明,该算法能找到满足QoS约束的全局最优解,并在资源预留的基础上较好地满足用户对于带宽、时延的要求.     

移动Ad Hoc网络中基于Qos的多路径路由协议研究

针对现有移动Ad Hoc网在大流量业务下无法提供高质量QoS保障的问题,通过推导证明提出了路径长度限制的路径稳定的约束关系,进而将QoS的判定因子引入一种确定性的最优权值约束路由算法进行实例化,并在该路由算法的基础上提出了基于QoS保障的多路径路由协议(MP-QAODV).通过仿真,验证了MP-QAODV协议在平均端到端时延、端到端数据分组投递率、归一化路由开销等方面优于AODV和AOMDV协议.     

基于自相似流量水平分级预测的网络队列调度算法

网络流量的自相似特性会导致网络中数据的突发状态持续,为有效降低网络流量突发引起的队列排队时延和分组丢失率,提高不同优先级业务的传输能力,保障业务服务质量需求,提出了一种基于网络流量自相似特性的队列调度算法——P-DWRR。该算法设计了基于自相似流量水平分级预测结果的动态权值分配方法及服务量子更新方法,并根据业务优先级和队列等待时间确定队列的服务次序,以减小数据分组排队时延,降低分组丢失率。仿真结果表明,P-DWRR算法在满足网络不同业务优先级要求的基础上,降低了数据分组的排队时延、时延抖动和分组丢失率,性能优于DWRR和VDWRR。     

Addressing self-similarity in optical switching networks by means of ant colony optimization

In this work, we propose the use of an Ant Colony Optimization (ACO) algorithm to mitigate packet loss in an optical packet switching network that carries self-similar traffic, which is known to have a great impact in the buffer performance in terms of loss probability as exemplified in this work. By adaptively routing the packets and balancing the network load, we demonstrate by some simulations the effectiveness of this approach when compared with a shortest-path routing scheme, achieving a performance that is comparable to the Poisson traffic scenario in some cases. The proposed algorithm can be used as a viable alternative to traffic shaping techniques.     

A routing scheme for connecting delay-sensitive urban vehicular networks to the IPv6-based internet

This paper proposes a routing scheme for connecting urban vehicular networks to the IPv6-based internet. In this scheme, the architecture based on vehicular domains is proposed to reduce the routing delay and packet loss. Based on this architecture, the intra-VD and inter-VD routing algorithms are proposed. In the intra-VD routing algorithm, a vehicle achieves the communications with the IPv6-based internet via the nearest access point, so the routing delay and packet loss are lowered. When a vehicle moves within one vehicular domain, its care-of address keeps unchanged. As a result, the extra routing delay and packet loss caused by the routing establishment due to the care-of address change are avoided. In the inter-VD routing algorithm, a vehicle can receive the data destined for the old and new care-of addresses from one access point, so the packet loss caused by the routing reestablishment due to the care-of address change is reduced. This scheme is quantitatively evaluated. Compared to the existing routing approach, our solution reduces the routing delay and packet loss by nearly 60 and 53%, respectively.     

Analysis of Distributed DDQ for QoS Router

In a packet switching network, congestion is unavoidable and affects the quality of real‐time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well‐known solutions for quality‐of‐service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.     

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.     

IP网络时延敏感型业务流自适应负载均衡算法

互联网对时延敏感的业务数据流,要求具有较低的端到端时延,但是网络拥塞的发生,将会使服务质量无法保证。基于链路关键度提出了一种新的自适应负载均衡路由算法(LARA,load adaptive routing algorithm),能最大限度地避开拥塞链路从而减少端到端延迟。该算法通过得到一个优化目标函数,并利用凸优化理论将优化目标函数分解为若干个子函数,最终得到一个简单的分布式协议。利用NS2仿真器在基于CERNET2真实的拓扑结构上进行仿真实验,同时与网络中能普遍部署的等开销多路径(ECMP,equal-costmulti-path)算法相比较,通过测试反馈时延、分组丢失率、流量负载,结果表明LARA具有更好的自适应性和健壮性,性能相比更优。     

Multipath Security Aware Routing Protocol for MANET Based on Trust Enhanced Cluster Mechanism for Lossless Multimedia Data Transfer

The dynamic nature of mobile nodes of ad hoc network is mostly affected by security problems which reduce data forwarding rate in multimedia sources. Due to the rapid growth of wireless applications, the different multitalented routing protocols are proposed in recent years. But the recent protocols are not efficient for multimedia applications, till now, specific security aware routing protocols are not proposed for multimedia data transfers. In this paper, we proposed trust enhanced cluster based multipath routing (TECM) algorithm. We use energy efficient PSO algorithm used to create cluster formation and cluster head, super cluster head are selected from trust values, which compute form proposed TECM algorithm. The multi trust factors are used for trust computation, such as frame/packet loss ratio, frame/packet forward energy, frame/packet receiving energy, routing overhead, received signal strength, frame/packet forward rate, average forward delay and protocol deviation flag. We then combine proposed TECM algorithm with standard multipath OLSR protocol (TECM-OLSR) to analyze the performance of proposed algorithm. The simulated results show that proposed TECM-OLSR protocol is very effective in terms of loss and delivery rate, delay, routing overhead and network lifetime compare to FPNT-OLSR.     

认知网络中的拥塞规避多径路由算法

链路拥塞导致的数据包传输延时或者数据包丢弃使得网络无法保证业务的Q0S,而目前普遍使用的链路状态路由算法不具有拥塞响应机制.本文针对以上问题,提出了一种能够快速规避拥塞的多径路由算法,该算法通过改进蚂蚁算法,在拥塞发生时采用双向蚂蚁寻路的方法,提高了新路径搜索的速度;使用新的寻路准则使其更满足认知网络的QoS需求.使用...     

HOPNET: A hybrid ant colony optimization routing algorithm for mobile ad hoc network

Mobile ad hoc network (MANET) is a group of mobile nodes which communicates with each other without any supporting infrastructure. Routing in MANET is extremely challenging because of MANETs dynamic features, its limited bandwidth and power energy. Nature-inspired algorithms (swarm intelligence) such as ant colony optimization (ACO) algorithms have shown to be a good technique for developing routing algorithms for MANETs. Swarm intelligence is a computational intelligence technique that involves collective behavior of autonomous agents that locally interact with each other in a distributed environment to solve a given problem in the hope of finding a global solution to the problem. In this paper, we propose a hybrid routing algorithm for MANETs based on ACO and zone routing framework of bordercasting. The algorithm, HOPNET, based on ants hopping from one zone to the next, consists of the local proactive route discovery within a node’s neighborhood and reactive communication between the neighborhoods. The algorithm has features extracted from ZRP and DSR protocols and is simulated on GlomoSim and is compared to AODV routing protocol. The algorithm is also compared to the well known hybrid routing algorithm, AntHocNet, which is not based on zone routing framework. Results indicate that HOPNET is highly scalable for large networks compared to AntHocNet. The results also indicate that the selection of the zone radius has considerable impact on the delivery packet ratio and HOPNET performs significantly better than AntHocNet for high and low mobility. The algorithm has been compared to random way point model and random drunken model and the results show the efficiency and inefficiency of bordercasting. Finally, HOPNET is compared to ZRP and the strength of nature-inspired algorithm is shown.     

A QoS aware joint design for wireless mesh networks

Wireless mesh networks (WMNs) provide Internet access to remote areas and wireless connections on a metropolitan scale. In this paper, we focus on the problem of improving the gateway throughput in WMNs while achieving fairness and supporting quality-of-service (QoS) differentiation for end-users. To address this problem, we propose a new distributed dynamic traffic scheduling algorithm that supports different QoS requirements from different users. We also develop a joint weight-aware channel assignment and minimum expected delay routing mechanism. Simulation results demonstrate the performance of the proposed work in terms of the achieved throughput and minimized packet loss ratio and delay.     

车载自组织网中基于蚁群算法的延迟感知路由协议

针对城市道路环境下车载自组织网( VANETs)中通信性能下降以及数据传输失败的问题,提出了一种基于蚁群算法的延迟感知路由( ACDR)协议。首先,建立双向车道的数学延迟模型;然后,根据提出的端点十字路口( EI)的概念,ACDR利用蚁群优化( ACO)寻找最佳路线,其中前向蚂蚁根据本地路段延迟以及当前十字路口与目的节点的端点十字路口之间的全局时延来选择路径,后向蚂蚁则负责在返回路径时更新信息素,同时,相邻十字路口之间利用贪婪转发算法进行数据包的传递。最后仿真比较了ACDR协议与连通性感知路由( CAR)协议的性能,结果表明提出的ACDR协议的数据包的传输延迟小,丢包率低,通信性能好。