基于排队论的最优流路由算法探讨

针对网络中时常发生网络拥塞问题,使用排队论理论研究网络传输最优化问题,结合实际传输过程中的影响参数,探讨了最优流路由算法。实验结果表明,本算法具有一定的可行性和正确性。     

考虑排队时延的系统保护通信网络路由选择算法

目前满足系统保护通信网络的路由算法是在综合时延和可靠性的要求下,计算一条快速且可靠传输的路径,而没有考虑到当电网发生故障或网络中通信量过大时,通信网络中许多节点的排队时延会极大地增加,忽略排队时延对路径传输总时延的影响会导致路径的错误选择,从而影响系统保护的实时性。针对此问题,提出了一种考虑排队时延的路由选择算法,用于计算信息传输总时延最小的最优路径,以提高系统保护通信的实时性。实验结果表明,通过本文提出的路由选择算法计算得到的路径在满足系统保护可靠性要求的基础上信息传输总时延最小。     

基于排队论的路由器缓存系统建模与分析

路由器是通信网络中重要的存储转发设备,其缓存大小与性能指标密切相关。文章以M/M/1/K排队系统为基础构建路由器缓存系统的模型,得出系统的性能指标丢包率和数据包的平均传输时延,并通过仿真分析探讨路由器缓存容量对系统性能的影响。最后,提出在不同网络环境下根据系统的技术指标设计路由器缓存容量的具体算法。     

Web网络下的异常路由数据监测技术研究

在Web网络环境下,路由器应用过程中利用信道传输介质数据会出现异常干扰数据,而传统路由数据监测技术很难准确辨别异常数据,并且存在不能承接Web网络的缺陷。针对上述问题,提出Web网络下的异常路由数据监测技术。对监控总框架进行优化设计,增设Web网络承接模块,导入多层次监测机制,通过Contra variant算法实现异常数据监测。设置仿真实验,实验结果表明,提出的数据监测技术能够有效地监控路由异常数据。     

基于Bloom Filter的云内容路由优化

随着国家三网融合战略的进一步推进,传统的“广播式”媒体内容分发模式已无法满足用户日益增长的双向“互动式”业务需求。利用云计算技术构建媒体云内容分发网络,实现媒体内容的弹性部署、高效分发来解决该问题,已成为下一代广电网络(NGB)的核心内容。在构建媒体云网络过程中,如何进一步改善用户的响应时延是必须考虑的因素。文中在此背景下,提出利用全局Bloom Filter优化媒体云网络中的内容路由。通过两种优化路由设计,使用户的平均响应时延得到有效下降。并采用排队网络对传统以及优化后的路由策略进行理论建模,使用OMNeT++网络仿真器对提出的路由策略进行仿真。其结论与仿真结果一致性良好。结果显示,优化后的路由策略,在不同的场景下,最多可节省65.2%的平均响应时延。     

基于位置的开放式容迟网络路由算法

移动环境下互联网接入网络频繁中断,需使用容迟网络协议.然而时间概率不确定性导致DTN路由算法的先验知识计算复杂,文中提出基于空间的路由算法以消除.进一步由接入路由器信息矩阵决定实现接入路由器的k集合,提出广义k选播以缓解概率不确定性,使用效用最大化的规划模型,在整个许可时间段和k个路由器之间进行路由和资源分配,结合DTN的托管传送,可以对多个目的地同时传送数据包.仿真验证了传输性能和鲁棒性整体较优,能灵活支持开放式网络拓扑结构变化.     

支持多速率传输的动态Ad hoc路由协议

该文提出了一种支持动态多速率传输的无线Ad hoc网络路由方案,它能够增加网络的吞吐量和减少分组的传输时延。该方案把路由功能分为两个部分:广域路由功能和本地路由功能。本地路由功能是一个独立的子层,负责在广域路由功能选择的中继节点之间适当地增加新转发节点,使最终路由中的每段链路都能使用高速率进行传输,从而减小数据发送过程中总的信道占用时间。该文设计了一种LDSR协议来执行本地路由功能。仿真结果显示了新的路由方案能够有效地利用网络节点的多速率传输能力,获得更好的网络性能。     

基于IP源路由的高速路由协议研究

带宽业务与多领域拓展性是新一代互联网的重要特点,这对网络路由器性能、服务能力提出了更高的要求。文中提出一种基于IP源路由机制的高速路由协议SR-HRP（Source Routing High Router Protocol）,区别于传统的源路由协议,SR—HRP源节点独立探索、维护到达目标节点的有效路径,在报丈传输时为路由器提供基于端口的转发信息,避免路由器因查询庞大路由表消耗的时间与资源。仿真结果表明,SR-HRP能够有效提高网络传输效率。     

节点容量限制对网络交通的影响

本文基于无标度网络模型，在静态局部路由策略的基础上，控制节点信息包排队长度，研究其对网络交通的传输影响。模拟发现：对网络节点容量进行合理范围的限制能够提高网络临界信息包产生率，缩短网络信息包传输时间。通过改变参数口值，得到网络临界信息包产生率以及网络信息包传输时间随参数卢变化曲线。结果表明：为了得到最佳网络临界信息包产生率，参数卢需在合适范围内取值；参数卢对网络信息包平均运输时间的影响主要原因在于参数卢对网络信息包等待时间的影响。     

基于位置信息的仓储容迟网络路由算法

仓储网络接入环境适合使用容迟网络(DTN)协议,然而渡轮的计划移动有时间的概率不确定性,从而导致DTN路由算法的先验知识计算复杂.本文提出基于位置信息的路由算法,由接入基站参数矩阵决定接入路由器集合,使用广义k任播缓解流量爆炸问题,最终使用效用最大化的规划模型,在整个许可时间段和k个路由器之间进行路由和资源分配,结合DTN的托管传送,可以实现对多个目的地同时传送数据分组.仿真结果表明,其传输性能和顽健性整体较优,能更灵活地支持仓储容迟网络拓扑结构的变化.     

Relay algorithm based on network coding in wireless local network

The network coding is a new technology in the field of information in 21st century. It could enhance the network throughput and save the energy consumption, and is mainly based on the single transmission rate. However, with the development of wireless network and equipment, wireless local network MAC protocols have already supported the multi-rate transmission. This paper investigates the optimal relay selection problem based on network coding. Firstly, the problem is formulated as an optimization problem. Moreover, a relay algorithm based on network coding is proposed and the transmission time gain of our algorithm over the traditional relay algorithm is analyzed. Lastly, we compare total transmission time and the energy consumption of our proposed algorithm, Network Coding with Relay Assistance (NCRA), Transmission Request (TR), and the Direct Transmission (DT) without relay algorithm by adopting IEEE 802.11b. The simulation results demonstrate that our algorithm that improves the coding opportunity by the cooperation of the relay nodes leads to the transmission time decrease of up to 17% over the traditional relay algorithms.     

Mini‐Slot‐Based Transmission Scheme for Local Customer Internetworking in PONs

We propose a new mini‐slot transmission scheme for a passive optical network (PON) in which each customer can be switched either to access mode or to internetworking mode dynamically. In this paper, we present the system implementation (called LAN‐PON) as well as the performance of the proposed transmission scheme to illustrate its feasibility and benefits. A mini‐slot scheme can rapidly reduce the queuing delay, which increases due to the flooding of the deflected packets in a deflection scheme. We evaluate the impact of mode switching time on the bandwidth gain (throughput) and delay of local area network (LAN) traffic in the LAN‐PON with a mini‐slot scheme. We also analyze a theoretical delay model of the proposed scheme. The simulation results demonstrate that switching time has an impact on LAN performance, and the average packet delay of the proposed scheme is significantly improved compared to that of the deflection scheme.     

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。     

无线多跳网络中机会路由效率增强研究(英文)

Opportunistic routing(OR) is an effective way to guarantee transmission reliability in wireless multi-hop networks.However,little research focuses on transmission efficiency.Thus,an analytical model based on open queuing network with Markov chains was proposed to evaluate the efficiency.By analyzing two typical ORs,we find duplicate transmission and collision avoidance overhead are the root reasons behind inefficiency.Therefore,a new scheme called dual priority cooperative opportunistic routing(DPCOR) was proposed.In DPCOR,forwarding candidates are configured with dual priority,which enables the network to classify forwarding candidates more effectively so as to reduce the back-off time and obtain more diversity gain.Theoretical analysis and simulation results show DPCOR achieves significant performance improvement with less time overhead compared with traditional routings and typical ORs.     

基于Restful的光传输网远程验收系统设计与实现

针对当前光传输网络现场工程验收存在的自动化程度低、耗时长、覆盖面不全、工作量大等问题,提出了一种基于Restful、由中国电信自主开发的北向接口进行远程验收、自动判断性能是否达标的系统方案。利用接口的服务能力,将光传输网设备的相关信息作为入参封装在接口中,调用接口查询设备的单机和系统性能指标,并依据光传输网设备的相关测试标准,对返回数据进行自动转换、分类、分析,输出验收设备的最终调测结果,为工程验收人员提供依据和参考,实现设备远程验收。通过在实际传输网中进行验证,该系统可自动采集和比对性能指标,输出验收结果,相比传统现场验收方式,在较短时间内实现了设备的远程验收,验收覆盖率高,同时无需借助仪表在多站点、长时间测试,提升了光传输网的验收效率。     

基于自相似业务的移动Ad hoc网络路由算法研究

该文分析了移动Adhoc网络中普遍存在但被忽视的自相似业务的路由和排队性能,提出了基于网络规划模型的多径备份路由优化功率(MBOP)算法。该算法利用多路径和备份路由,并对网络的发射功率进行优化,适用于网络结构动态变化的移动无线自组织网络。仿真结果表明,该算法可以显著改善节点的排队性能,提高网络的吞吐量改进时延性能。     

The building, analyzing and simulating of a multimedia networkbased on CATV system

This work present the design for an enhanced network system based on CATV and CSMA/CD. It is for real time and multimedia transmission. The object-oriented technique is also incorporated into a state chart to design the network, referred to herein as OOSTD. In addition, the multimedia network is thoroughly analyzed and the system is simulated by a queuing model and implemented. The analysis and simulation results confirm that the throughput and delay of the MORENET system are better than the conventional CSMA/CD or multi-channel CSMA/CD network     

基于OFDM技术和自组网技术的海上频谱感知传输系统研究

控制电磁频谱权成为控制信息权的核心,战场频谱管理是夺取控制电磁频谱权的重要保障.电磁频谱监测与管理系统中需要进行频谱信息的传输,而数据传输系统就是实现这个功能的关键.由于海上气象条件复杂,网络信号稳定性不佳,舰载电磁监测设备远离海岸而且机动性强.针对这一点,提出了一种基于OFDM技术与移动自组网技术的海上频谱感知传输系统,完成监测信息的远程实时传输.     

A framing strategy for congestion management

A congestion management strategy for integrated services packet networks that is robust with regard to transmission speed and network size is proposed. The strategy supports several classes of services with zero loss and different delay bounds as well as services without stringent loss and delay guarantees. Loss-free and bounded-delay transmission is accomplished by means of an admission policy which ensure smoothness of the traffic at the network edge, and by a service discipline called stop-and-go queuing, which maintains the traffic smoothness throughout the network. Both the admission policy and the stop-and-go queuing are based on a time framing concept described elsewhere by the author (IEEE Trans. Commun., vol.39, Dec.1991). This concept is further developed to incorporate several frame sizes into the strategy, thereby providing flexibility in meeting throughput and delay requirements of different applications. Stop-and-go queueing is realizable with minor modification to a first-in first-out (FIFO) queueing structure