TPDCM:一种新型的分布式拥塞管理方案

提出一种新型的面向区分服务网络的分布式拥塞管理方案,基本思想是利用拥塞状态反馈信息在边缘节点或主机上实施拥塞管理。该方案主要包括三个组成部分:流量控制信息协议、早期拥塞检测和流量控制算法。该方案具有以下特点:(1)在核心网络中,拥塞控制机制独立于特定的传输层协议;(2)对将要发生的拥塞做出快速响应;(3)降低网络的分组丢失率;(4)不需要在网络核心节点中保存每个传输流的状态信息。实验结果表明,与标准的区分服务网络相比,该方案能在TCP和UDP聚集之间公平地分配带宽并能显著地降低分组丢失率。     

DiffServ网络的拥塞控制策略

本文首先分析了区分服务网络体系结构模型,然后讨论了基于队列长度的各种拥塞控制算法,并分析了一种新的主动队列管理算法BLUE,同时为区分服务网络的拥塞控制指出了进一步研究的方向,即:在DiffServ域的入口和出口节点之间增加控制分组,并选择合适的QoS参数来标记控制分组.     

基于反馈的区分服务网络拥塞管理方案研究

为了有效解决RED算法拥塞响应滞后以及在聚集类之间公平性不足的问题,提出建立一种基于早期拥塞指示反馈的区分服务网络模型,并在该模型上采用优先级早期随机检测算法。在网络入口节点对分组进行分类、聚集与监测,各队列按优先级设置不同队列长度阈值,当平均队列长度或各队列长度达到相应阈值范围时,立即触发不同程度拥塞指示包向源端反馈。使用改进的NS进行了仿真实验,实验结果表明该算法使得拥塞指示能尽可能快地到达TCP源,有效地降低路由器中的丢包率。提高网络利用率,并且为不同的聚集类提供不同优先级服务,保障了聚集类的公平性。     

区分服务网络的一种基于聚集状态的动态资源管理方案

提出了一种适用于区分服务网络的确保服务的动态资源提供方案:基于聚集状态的分布式动态资源管理。该方案在网络节点基于聚集状态进行接纳控制和动态资源预留,不需要核心节点保存单个流的状态,因此,该方案是可扩展的。方案包括一种轻量级动态资源预留协议和网络节点动态资源管理的相关算法,如状态建立、管理和接纳控制决策算法。该方案中,网络节点聚集状态的建立使用了基于实时流量测量的方法,在提供服务质量(QualityofService,QoS)保证的同时,得到了统计复用的增益,提高了资源的利用率,简化了信令协议,也使该方案具有很好的健壮性。     

区分服务网络基于测量的接纳控制方案的设计与应用

提出了一种分布式可扩展的接纳控制方案，其目的是为区分服务网络提供端到端服务质量（Quality of Services,QoS)保证，该方案主要由以下部分构成：（1）连接接纳控制协议，主要负责主机和网络节点以及网络节点和带宽代理之间的信息传送，实现对连接请求的串行操作；（2）位于网络核心节点的可用带宽估计算法；（3）位于网络边缘节点的接纳控制算法；给出了该方案在视频传输方面的应用实例；利用多种网络拓扑结构和QoS指标评价该方案的性能，实验结果表明该方案能准确地控制可接纳区域和提高网络资源的利用率。     

高效自适应的抗污染攻击网络编码传输方案

本文主要研究网络编码在抗污染攻击中的应用,针对中间节点对收到的所有编码包进行验证浪费网络资源和目的节点解码速率慢等问题,提出一种高效自适应的抗污染攻击网络编码传输方案-EANC(Efficient and Adaptive Network Coding transmission scheme against pollution attack)。EANC方案在数据分组编码阶段,利用按照网络编码的时间和空间特性构造的线性子空间签名方案准确地验证数据分组是否被污染从而有效控制污染数据分组的传播,并且能使中间节点调节验证步骤使之自适应于当前网络的污染程度,从而提高验证效率;在目的节点解码阶段,EANC方案利用目的节点重传恢复机制降低解码恢复时延。仿真结果表明,EANC方案能够减少子空间的签名长度并且降低目的节点解码恢复的平均时延。     

传感器网络中基于虚拟坐标的节点调度方案

首先,建立了极大相似分布模型;其次,引入节点的虚拟坐标的概念,用来替代节点实际的位置坐标.在此基础上,提出了一种分布式的、与节点位置无关的节点调度方案.方案由一个覆盖算法和一个连通算法组成,方案中的覆盖算法利用虚拟坐标信息进行分组.在不需要节点位置信息的条件下,使各个分组内的传感器节点较为均匀地分布在目标区域.该方案不仅解决了任意分组中的节点充分覆盖目标区域的问题,而且保证了网络的连通.仿真实验表明,该节点调度方案在覆盖率、维持分组连通时额外加入到分组内的节点个数以及网络生存时间等性能上均优于与节点位置无关的节点随机调度协议.     

一种鲁棒性强的无线传感器网络位置隐私保护方案

传统无线传感器网络（WSNs）位置隐私保护方案难以解决安全性与网络能耗之间的均衡,为了提高网络隐私信息的安全性,提出一种鲁棒性强的无线传感器网络位置隐私保护方案.首先通过增加伪源节点和伪汇聚节点防止攻击者获得关键节点的位置信息;然后采用伪汇聚节点分组、概率丢弃冗余数据包降低网络资源消耗;最后在Matlab 2012平台下进行仿真对比实验.结果表明：该方案可以提高网络攻击事件检测率,降低网络时延,有效地保护源节点和汇聚节点的位置隐私.     

两比特区分服务实现策略研究

1.引言区分服务是近两年的一个研究热点,其目的是在传统的IP分组交换网络上为用户提供较大粒度的服务质量保证。采用的实现手段是简化网络内部节点的服务机制和简化网络内部节点的服务对象。区分服务的基本思想是在网络边缘节点保存流状态信息,并根据用户的流规定和资源预留信息对流入分组进行分类、整形、聚合为不同的流聚集,并将处理结果信息保存在IP包头的DS字段中,称为DS标记(DSCP)。内     

一种区分服务网络的设计与实现

给出了DiffServ网络的一种设计与实现，提出了一种有效的资源管理模型。在该模型中，存在一个带宽代理(Bandwidth Broker)同步多个边界节点的接纳控制，负责区分服务网络之间的SLA(Server Level Agreement)协商，进行路由器配置；边界节点使用RSVP协议为集聚流预留资源；RSVP使用预计算QoS路由寻找路径。整个模型不仅综合了已有资源管理方案的优点，而且保持了区分服务网络的可扩展性。     

一种基于入口地址标记的DoS攻击防御模型

对因特网上的DoS攻击进行了分类，分析讨论了已有的各种防范技术，提出了新的在AS的入口路由器端进行地址标记的IAM模型，使受害主机能通过分析攻击数据报中的地址标记信息，直接获取攻击入口路由器地址。随后可通知该路由器采取拦截或过滤等防范措施。     

A Novel Framework for IP DiffServ over Optical Burst Switching Networks

This paper presents a novel framework for IP Differentiated Services (DiffServ) over optical bursts witching (OBS), namely, DS-OBS. The network architecture, functional model of edge nodes and core nodes,the control packet format, a novel burst assembly scheme at ingress nodes and scheduling algorithm of core nodes are presented. The basic idea is to apply DiffServ capable burst assembly at ingress nodes and perform different per hop behavior (PHB) electronic treatments for control packets of different QoS class services at core nodes. Simulation results show that the proposed schemes can provide the best differentiated service for expedited forwarding (EF), assured forwarding (AF) and best effort (BE) services in terms of end-to-end delay, throughput and IP packet loss probability.     

An admission control scheme for end-to-end statistical QoS provision in IP networks

This paper presents a distributed and scalable admission control scheme to provide end-to-end statistical QoS guarantees in IP network.The basic idea of the scheme is that the ingress routers make admission control decisions according to the network status information obtained by sending probing packets along the selected routing path.Each router passively monitors the arriving traffic and marks the probing packets with its network status.The performance of the presented scheme is evaluated with a variety of traffic models,QoS metrics and network topologies,The simulation results show that the proposed scheme can accurately control the admissible region and effectively improve the utilization of network resource.     

Edge-limited scalable QoS flow set-up

Although the Differentiated Services architecture supports scalable packet forwarding based on aggregate flows, the detailed procedure of Quality of Service (QoS) flow set-up within this architecture has not been well established. In this paper we explore the possibility of a scalable QoS flow set-up using a sink-tree paradigm. The paradigm initially constructs a sink tree at each egress edge router using network topology and bandwidth information provided by a QoS extended version of Open Shortest Path First (OSPF), which is a widely used link-state routing protocol. Our sink-tree paradigm dynamically reallocates network bandwidths online according to traffic demands. As a consequence, our paradigm easily supports QoS routing, resource allocation, and admission control at ingress edge routers without consulting core routers in a way that the QoS flow set-up time and overhead are minimized. Simulation results are very encouraging in that the proposed methodology requires significantly less communication overhead in setting up QoS flows compared to the traditional per-flow signaling-based methodology while still maintaining high resource utilization.     

Linux环境下路由器中的网络带宽管理

Linux是目前广泛用于路由设备中的操作系统,而流量管理是这种网络操作系统的一个重要功能.研究了Linux系统的流量管理机制,发现当前Linux系统所采用的在网络接口的出口实现的基于网络包调度的流量管理机制缺乏对于网络带宽在系统范围的全局性的管理,也缺乏对于输入流的网络处理的有效管理和调度,从而造成不必要的CPU资源的浪费.为解决这一问题,提出了一种新颖的网络带宽管理机制,它通过调度网络协议处理所占用的CPU时间来实现带宽管理.这种新的机制将网络带宽的管理和调度从网络接口的出口点转移到处理接收到的网络包的系统软件中断处理程序中,从而克服了原来的流量管理机制的缺点.通过系统实现和对比实验,发现该机制本身给系统带来的负载小于Linux原来的流量管理机制,同时可以提供更好的流量隔离,并且能够有效地节省用于网络处理的CPU资源.     

Interleaved Traffic Splitting: A promising technique to solve False Timeout

In this paper, we analyze the False Timeout (FTO) problem that TCP flows suffered in OBS networks and propose Interleaved Traffic Splitting (ITS) to solve the problem. We show that the collision loss of ACK bursts may also cause FTO, which has been neglected by previous researchers. As TCP Sack is designed to recover from multiple packet losses, we find that a Sack flow can recover its data transmission without triggering retransmission timeout if packet loss is not too severe. This suggests limiting the number of packets carried by a single burst. In ITS, this is achieved by carrying out a parallel, interleaved burst assembly process at each ingress OBS edge router. We show that ITS tackles the FTO problem caused by the loss of both data and ACK bursts. Unlike other existing approaches, the ITS scheme requires only modification to the assembly/de-assembly mechanisms implemented at the edge routers. It does not add complexities to the network management or the router design. In this paper, both analytical and simulation results are presented to demonstrate the performance improvement of ITS. Our analysis further shows that the use of two parallel bursts is optimum for ITS.     

基于MAC认证的新型确定性包标记

在入口路由器数目大于攻击者数目时,基于Hash摘要的DPM(HDPM)算法的假阳率远高于其分析说明,由此提出一种基于MAC认证的新型确定性包标记(NADPM)方法,利用IP地址和MAC认证消息根据不同网络协议选择不同位数灵活地进行包标记。理论分析和模拟结果表明,该NADPM方法的假阳率远低于HDPM算法,且其最大可追踪攻击者数达140 000。     

Enhanced bulk scheduling for supporting delay sensitive streaming applications

Providing end-to-end delay guarantees for delay sensitive applications is an important packet scheduling issue with routers. In this paper, to support end-to-end delay requirements, we propose a novel network scheduling scheme, called the bulk scheduling scheme (BSS), which is built on top of existing schedulers of intermediate nodes without modifying transmission protocols on either the sender or receiver sides. By inserting special control packets, which called TED (Traffic Specification with End-to-end Deadline) packets, into packet flows at the ingress router periodically, the BSS schedulers of the intermediate nodes can dynamically allocate the necessary bandwidth to each flow to enforce the end-to-end delay, according to the information in the TED packets. The introduction of TED packets incurs less overhead than the per-packet marking approaches. Three flow bandwidth estimation methods are presented, and their performance properties are analyzed. BSS also provides a dropping policy for discarding late packets and a feedback mechanism for discovering and resolving bottlenecks. The simulation results show that BSS performs efficiently as expected.     

Distribution-based bandwidth access scheme in slotted all-optical packet-switched networks

The common approach in an ingress switch to access a slotted all-optical packet-switched network is the TTA (timer-based/threshold-based bandwidth access) bandwidth access scheme in which packet differentiation is provided by a time-out mechanism. In contrast, we propose in this paper the DA (distribution-based bandwidth access) to access the slotted all-optical packet-switched network within a DiffServ domain. Each torrent (the traffic between each pair of ingress and egress switches) is given a bandwidth measured in slots within a frame at an ingress switch. The slots from each torrent are evenly distributed throughout the frame and among the output wavelengths/fibers of the ingress switch. Comparing to the most commonly used technique TTA, we demonstrate that our DA approach can achieve the following: (1) provide each traffic torrent a fairer access to the network bandwidth; (2) reduce the probability of the slot drop rate at the optical network; (3) reduce the excessive bandwidth allocation by the bursty torrents; (4) balance the traffic load much better on wavelength channels; and (5) guarantee a stable edge switch operation to service traffic in which the traffic generation rate to the optical network is lower than the traffic service rate.