New insights on survivability in multi-domain optical networks

With the development of intelligent optical networks and the general multi-protocol label switching (GMPLS) technique, the seamless convergence between IP network and optical network is no longer be a dream but a practical reality. Similar to the Internet, current optical networks have been divided into multiple domains each of which has its own network provider and management policy. Therefore, the development of multi-domain optical networks will be the trend of new-generation intelligent optical networks, and GMPLS-based survivability for multi-domain optical networks will become a hot topic of research in the future. This paper provides a comprehensive review of the existing survivable schemes in multi-domain optical networks and analyzes the shortcomings of current research. Based on previous studies, we present possible challenges and propose new ideas to design efficient survivable schemes to guide the future work of researchers in multi-domain optical networks.     

A Novel Framework and the Application Mechanism with Cooperation of Control and Management in Multi-domain WSON

Multi-layer and multi-domain optical networks have drawn much attention in current research, and the wavelength switched optical network (WSON) is viewed as one of the best solutions in optical networks. In this paper, a novel Cooperative Control and Management Framework (CCMF) in multi-domain WSON is proposed to support the arising intelligent applications and optimize resource utilization with more scalability and robustness. In CCMF, we focus on the mechanism with the consideration of requirements of intelligent applications with complex flows, performance guarantees and traffic engineering in a traditional optical network. Thus, a combined provisioning approach, synergetic between the control plane (CP) and the management plane (MP), is presented with the policy based management system, in which a mobile agent is introduced to support the communication between MP and CP. Furthermore, one application, a novel multi-domain impairment aware routing and wavelength assignment (MIA-RWA) algorithm at the Bit Error Rate level, based on the proposed CCMF, is presented. It is proposed to improve the routing performance in multi-domain WSON. Finally, comprehensive simulations are conduced to verify the effectiveness of CCMF and the proposed mechanisms.     

SDN网络虚拟化中规则映射研究

软件定义网络（SDN）为网络虚拟化提供了新的解决方案,通过网络虚拟化技术可以将一套基础设施虚拟化为多个逻辑网络从而满足不同的网络需求.本文研究了SDN网络虚拟化时多个物理交换机虚拟为一个大虚拟交换机的过程中,虚拟网络规则与物理网络规则的映射问题.综合考虑链路负载、规则分布以及节点负载,提出了三段式规则映射优化算法.首先根据虚拟网络的规则请求生成组播源节点和目的节点集,采用MPH算法生成规则映射树;然后采用入节点最近原则,将虚拟网络规则请求的指令序列部署到规则映射树中的中间节点和叶子节点中;最后考虑节点负载,对规则部署进行微调,最终生成虚拟规则映射策略.通过仿真实验,与直接边缘节点部署相比,平均降低了网络节点规则总数量40%以上.     

基于WSNs节点权重的网关接入异构网络研究

在无线传感器网络(WSNs)中,虽然现有网关节点的设计已经将多网融合的传输方式引入进来,但很少有综合考虑整个网关节点的性能,包括吞吐量、丢包率、耗电量和成本开销等,并且少有深入探讨多网选择切换方法。针对此现状,引入传感器节点权重的概念,从不同权重的传感器节点需要不同的传输策略出发,以数据上传互联网为目的,提出了一种网关接入异构网络的框架,并在此框架中综合考虑吞吐量、耗电量和接入所需费用3个方面,提出了一种多目标优化的模型,之后给出启发式的近似算法。实验结果表明:在保证传感器网络中数据可靠传输和能耗稳定的前提下,提高了数据传输效率,并适当降低了网关接入异构网络的成本,为网关接入异构网络传输数据提供了一种可靠的方案。     

链路预测模型下的无人机网关选择算法

针对无人机自组网和地面控制站通信时网关节点持续时间短并由此带来的数据传输时延过大和成功率不高等问题,提出了一种基于无人机-地面控制站链路状态预测的网关选择算法.该算法通过建立基于无人机活动模型的预测和基于无人机运动趋势的预测,从而选择与地面控制站连接时间较长的节点作为网关候选节点.此外,通过使用函数计时机制选择网关选择参数最大的节点作为网关节点,有效避免分布式网关选择算法中随机延迟机制导致的不必要的网关切换.仿真结果表明,与现有的无人机分布式网关选择算法和移动自组网分簇算法相比,该算法有效延长了网关节点持续工作时间,并使无人机网络与地面控制站通信时的数据传输时延、数据传输成功率等性能得到提升.     

多入口单IP集群接口方案及其实验分析

集群系统实现单一用户访问点的常用方法是设置一个前端机统一进行用户请求的转发，这种方法很好的解决了集群的单一入口问题，但容易引起单点失效，性能也难扩展．提出并实现了一个多入口解决方案，即：由多个节点来承担上行请求的调度任务，各节点具有相同的IP地址和MAC地址，通过对源IP的过滤实现数据包的分流，多接口的存在对用户是透明的，通过多入口，集群的可扩展性、可用性均获得了增强．分析和测试表明，这种接口方案可显著的提高集群系统接口的并发访问数，实现也非常简单。     

基于改进Das协议的无线传感器网络用户认证协议UAPL

针对在无线传感器网络中采用用户认证的方式获取节点数据时,容易出现密码被破译,以及容易遭受多种网络攻击等安全性问题,在改进Das协议的双因素身份验证的基础上,引入了用户与网关、网关与传感器节点之间的互相验证机制以及用户密码变更机制,提出了UAPL协议。UAPL协议具有防止网关节点旁路攻击、伪装攻击等网络攻击的安全验证机制,提供的密码变更防护能防止由于密码泄露而引发的安全问题。实验结果表明,UAPL协议与其他改进Das协议相比具有较高的安全性。     

A congestion control scheme for window flow controlled computer networks

In this paper we introduce a congestion control scheme that is appropriate for virtual circuit networks that use fixed routing and a window mechanism for end-to-end flow control. The scheme relies on the notion of balancing the flow of traffic at the local buffer pool of the outgoing links at every node of the network. The effectiveness of the scheme at the intermediate nodes of a network as well as at the network entry point and at the gateway node of interconnected networks is studied via simulation.     

A survivable routing algorithm with differentiated domain protection based on a virtual topology graph in multi-domain optical networks

In this paper, we propose a novel differentiated domain protection (DDP) scheme to address survivability in multi-domain optical networks. Survivable routing in multi-domain networks is a challenging algorithmic problem because it requires choosing links that provide adequate protection both between domains and within domains that may offer different protection services. To satisfy the survivability requirements of different domains, DDP considers differentiated protection schemes, i.e., dedicated protection, shared protection, or no protection in different domains. In order to respect the principle of transparent management in multiple domains, DDP abstracts a multi-domain optical network to a virtual topology graph (VTG) for solving routing between domains. Simulation results show that DDP, unlike traditional schemes, can provide trade-off between protection methods and also allows better resource utilization.     

无线传感器网络移动Sink网关系统的设计与实现*

针对无线传感器网络传统Sink网关的不足,提出了一种基于PDA的移动Sink网关系统的设计与实现方案,对其设计目标、体系结构和工作原理进行了论述,重点讨论了PDA与Sink节点之间的连接,PDA与Sink节点、PDA与GPS接收机及PDA与控制终端之间通信的一些关键技术.     

一种高效快速的无人机自组网网关切换算法

针对无人机自组网网关节点突然失效给网络性能和网络可靠性带来的不利影响,提出一种高效快速的无人机自组网网关切换算法。首先,设计了备份网关的选择机制,通过考虑网关节点和邻居节点之间的距离因素从而选出备份网关节点;其次,改进了网关失效识别机制,备份网关可以更快地检测出网关节点是否失效;最后,提出了高效快速的无人机自组网网关切换机制,减少了网关功能失效的时间。仿真结果表明,所提算法可以降低无人机自组网网关的失效时间,提高无人机网络的可靠性并使时延、吞吐量等性能得到了提升。     

多域光网络中应用混合拓扑聚合的分段保护算法

研究了多域光网络中的路由保护问题;为了克服多域光网络中可扩展性约束,提出了一种混合拓扑聚合方法。该方法结合了全连通和生成树拓扑聚合的优点,在网络中需要存储和发布的链路状态信息与聚合信息反映实际物理拓扑的精确性之间进行了折中;然后在此混合拓扑聚合方法的基础上,提出了一种基于查询机制的多域分段保护算法。仿真表明,相比传统的多域保护算法,该算法阻塞率低,可扩展性好。     

无线自组织网络GDSR的路由算法研究

针对无线自组织网络（Ad‐Hoc）中DSR路由算法在路由查询时产生的洪泛广播问题,介绍了网关动态源路由协议（Gatew ay Dynamic Source Routing ,GDSR）,着重阐述了该算法的新节点入网路由查询机制、节点路径查询机制、基于优先级的对数函数退避算法等。本文实现了该路由算法,并在实际环境中测试验证了该路由协议。     

基于物联网技术的休闲农业智能监测与培育系统

将农业相关技术和物联网技术相结合,构建了休闲农业智能监测与培育系统。介绍了该系统的总体结构及软硬件设计方法。其中传感网络通过网关接入传输网络,与远程智能中心交换数据,智能中心则将接收到的数据进行分析与处理,由有关人员通过网络浏览休闲农业园区和查阅信息,结合专家决策系统,并根据实际情况对作物生长制定培育策略或有效控制等,从而为休闲农业的智能化提供一种有效的解决方案。     

基于分布式路径计算单元的多域光网络组密钥管理方案

针对分布式路径计算单元（PCE）架构下多域光网络的通信特点和密钥管理需求，提出一种该架构下的组密钥管理方案。首先使用超图理论对分布式PCE架构下的多域光网络密钥关系进行建模得到两层式密钥超图；然后在自治域层采用基于自认证公钥密码体制和成员过滤技术的密钥管理方法，在PCE层采用基于椭圆曲线密码体制的组密钥协商方法；最后完成密钥的产生、分发、更新和动态管理，较好地解决了成员的私钥保密性问题和第三方节点的冒充问题，减少了密钥更新时的计算开销。性能分析显示，该方案具有前向安全性、后向安全性、密钥保密性和抗合谋攻击等特点，与典型的分散式方案相比，在密钥存储量、加解密次数和通信开销等方面取得了较优的性能。     

基于CAN总线和GPRS的车载传感器网络平台的实现

给出了基于CAN总线和通用分组无线业务(GPRS)的车载传感器网络平台的解决方案和软件、硬件的实现。结合汽车轮速传感器,说明了传感器节点的信号处理和数据计算。通过设计CAN通信模块,实现车载传感器数据的网络化传输;采用包含GPRS模块的传感器网关节点,实现车载传感器与远程计算机间的无线数据通信。该车载传感器网络平台具有很强的通用性。     

NAT-PT转换网关在netfilter框架中的实现

由于在IPv4向IPv6过渡的过程中,两种网络将共存,所以这两种网络之间的通讯是必须解决的问题.应用NAT-PT转换网关是解决这一问题的一种方法.首先对NAT-PT机制进行了研究,着重讨论了NAT-PT机制中的地址转换操作过程,然后对Linux Netfiltr功能框架作了介绍.最后提出了一种基于netfilter功能框架的NAT-PT转换网关的一种模块化设计.这种模块化的NAT-PT转换网关具有实现简单和易于进行进一步功能扩展的特点.     

一种基于故障时间的可调域间出口选择算法

在大型Internet服务提供商中,BGP (border gateway protocol)出口路径选择常常采用"热土豆"机制.然而研究表明,该机制具有相当大的局限性以及出口调节的间接性,它容易影响域间路由的健壮性.针对"热土豆"机制的缺点,出现了一些新的BGP出口路径选择机制和算法.然而,这些方法在解决问题时往往忽略网络运行过程中经常出现的IP链路故障或故障持续时间的影响.提出了一种基于故障时间的可调域间出口路径选择算法,该算法能够根据流量工程的目标、路由稳定性等要求进行动态的调整,同时满足路由变化的实时性.模拟实验结果表明,该算法能够有效地在多个目标之间达到平衡.     

无线传感器网络与TCP/IP网络互联通信技术研究

提出了无线传感器网络与Intemet互联通信技术的代理服务器系统结构.设计了具有网络接口功能的代理网关节点.该节点作为无线传感器网络与Internet互联通信的代理网关,实现了远程访问和获取传感器网络监测的信息.给出了精简化的TCP/IP互联协议,以及代理网关主处理程序的软件实现.     

On-demand channel reservation scheme for common traffic in wireless mesh networks

Wireless mesh networks (WMNs) have recently gained momentum as a new broadband internet access technology to provide internet traffic. These networks have unique characteristics that make them different from ad hoc networks. These differences are as follows. First, WMNs are composed of static mesh routers that are equipped with multiple radio interfaces and turn each interface into a non-overlapping channel. These additional interfaces can create multiple concurrent links between adjacent nodes. Second, most of the traffic in WMNs is directed towards the gateway. Third, both local traffic and internet traffic are relayed by the mesh router to indeed destination. The Multi-Radio Ad hoc On-Demand Distance Vector (AODV-MR) developed to support multi-radio and does not take into account above-mentioned WMNs characteristics. In this paper, we propose an on-demand channel reservation scheme to reserve some of mesh router radio interfaces to support the gateway traffic while the remaining interfaces can be used to support the local traffic. Our scheme establishes high throughput paths for the traffic destined at the gateway, reduces the intra-flow and inter-flow interferences as well as to support full duplex node transmission.The scheme allows the gateway to assign a list of channels for each received gateway routing discovery message. Simulation results show that our proposed scheme significantly improves the performance of multi-radio multi-channel wireless mesh networks.