无线传感器网络的 RPL 路由协议研究

路由协议执行网络拓扑描述、路由选择和数据包转发的功能,影响整个网络的性能和存活时间.现有的路由协议需要发送大量数据包维护网络拓扑,以及大量的存储空间来存储路由条目.由于硬件的限制,无线传感器节点无论是能量,还是其处理能力、存储能力都受到极大的制约.因此,IETF RoLL 工作组提出了一种针对低功耗有损网络的 IPv6路由协议,即 RPL 路由协议.文中对 RPL 路由协议的拓扑构建过程、数据包路由过程和 Trickle 定时器的算法等进行了分析,通过使用 COOJA 仿真工具对其进行仿真,验证了 RPL 路由协议在低功耗有损网络中具有较高的性能     

基于IPv6的WSN最佳转发路由协议

基于IPv6的无线传感器网络引入TCP/IP架构,网络层遵循IPv6相关标准.现有的无线传感器网络路由协议不能直接应用,因此有必要为基于IPv6的无线传感器网路(如6LoWPAN网络)设计新的路由协议.针对基于IPv6的WSN其CPU、存储、通信及能量资源高度受约束的特性,提出了一种最佳转发路由协议.该协议获取邻居节点的链路估算、成本估计和RSSI值,然后基于这些参数计算各邻居节点的最佳转发值,选择拥有相对最佳转发值的节点作为数据包转发的下一跳.试验测试结果表明,相比RIP和贪婪转发路由协议,该协议提供了更好的吞吐量性能,吞吐量分别高出11％和43％.     

采用分段哈希方法的IPv6路由查找算法研究

分析了现有IPv4路由表查找算法和IPv6地址的特性以及主干网路由表的前缀分布特点,借鉴LFT哈希表结构简单、查找快速的特点,提出了以32bits为查找路由前缀起点的分段哈希表和多分支Tile树相结合的IPv6路由查找算法.该算法结构简单、查找效率高、易于更新,多数情况下只需一次内存访问就可查找到路由信息,提高了IPv6主干网路由器转发速度,以满足下一代互联网IPv6发展的需求.     

基于移动IPv6的分层式路由

移动节点在两个不同子网之间移动时将产生切换,这里简单介绍了移动IPv6的原理,对移动节点越区切换技术作了详细的分析HMIPv6,提出一种基于分层机制的移动IPv6路由管理模型。该模型支持路由优化,能在域内、域问移动时实现快速切换以减少延迟,提高网络资源利用率。     

IPv6地址自动配置中接口ID的生成算法

IPv6协议的一大特点是支持主机和路由器的地址自动配置,典型的IPv6单播地址由全局路由前缀、子网ID和接口ID组成.其中,全局路由前缀和子网ID可以通过路由通告得到,接口ID的自动生成在无状态地址自动配置方式中是非常重要的.本文给出了由MAC地址转换成接口ID的EUI-64转换算法.     

基于无冲突哈希表和多比特树的两级IPv6路由查找算法

为了提高IPv6的路由查找效率,根据IPv6路由前缀分布规律和前缀层次关系,提出了基于无冲突哈希表和多比特树的两级IPv6路由查找算法。该算法将地址前缀划分区间并按长度为32,40,48比特分别存储于3个哈希表中,剩下不足的前缀比特由多比特树存储,IPv6路由查找时在无冲突哈希表和多比特树中两级查找。实验表明,该查找算法的平均查找路径数为1.0~1.7,适用于高速的IPv6路由查找。     

一种基于子网跳变的IPv6 MTD模型

针对IPv6网络通信中通信节点及通信数据的安全性问题,受跳频通信启发,提出一种基于子网跳变的IPv6 MTD模型。该模型提出一种全Hash随机地址生成算法,子网前缀和接口标识同时跳变,保证地址随机性。设计一种基于"预公告"和"后清除"两个策略相结合的跳变机制,保证通信持续性。理论分析与实验结果表明,该模型可有效抵抗节点追踪、DDo S、流量截获,保护网络安全。     

使用Hash表和树位图的两级IPv6地址查找算法

为了提高IPv6地址查找效率,在分析IPv6路由前缀长度分布规律的基础上,提出了基于哈希表及树位图(Tree-bitmap)的两级IPv6地址查找算法.算法将长度为16,32,48和64比特的前缀分别存储在4个Hash表中,其余前缀的前16,32和48比特利用已有的Hash表存储,剩余的不足16比特的部分前缀利用树位图存储,并将树位图的入口地址保存在Hash表中.IP地址查找时在Hash表和树位图中进行两级查找.实验表明,该查找算法的平均内存访问次数为1～2,最坏情况下为7,适用于高速IPv6地址查找.     

分段存储的CAM+SRAM高速IPv6路由查找方案

为了提高路由查找的速度,路由器的转发单元目前大多采用基于CAM的硬件解决方案。论文针对IPv6路由器的特性,设计并实现了一种分段存储的“CAM+SRAM”高速路由查找机制,有效地解决了单块CAM容量不足、无法满足地址位较宽的IPv6分组路由查找的缺点。该方案已经用于国家“863”重点项目“IPv6路由器”中,取得了良好的效果。     

一种基于Trie的IPv6路由查找方案

随着Internet的迅猛发展,IPv6技术必将成为主流.于是,如何高效地在路由表中查找匹配128位IPv6地址,成为了IPv6 技术发展的一大制约因素.经大量研究表明,Trie数据结构是实现高速路由查找和报文转发的关键.结合IPv6的地址结构特点,设计出基于Trie数据结构的查找算法,提高了路由查找效率以及报文转发速度.     

Quality of Service Support in RPL Networks: Standing State and Future Prospects

The development of IP-based Internet of Things (IoT) networks would facilitate more effective end-to-end IP network architectures, but it remains a challenge. Network routing needs to be effectively addressed in the IoT environments of scarce computational and energy resources. Accordingly, the Internet Engineering Task Force (IETF) has specified the IPv6 Routing Protocol for Low Power and Lossy Network (RPL) to provide a bespoke IPv6-based routing framework for IoT networks. However, RPL comes with no Quality of Service (QoS) support which is an essential requirement for many IoT applications. The network research community has introduced a number of research proposals enhancing RPL with different QoS solutions. This paper presents a review of these proposed solutions and aims to establish a firm understanding of recent QoS developments for RPL and possible areas for future IoT routing research. The focus is on comprehending the protocol and networking properties that can affect QoS performance in RPL networks. Consideration is also given to different objective functions developed for addressing varying QoS aspects such as throughput, delay, and packet loss. RPL is also extended in a number of QoS solutions following different approaches at the MAC, network, and application layers. However, there is still a need for further developments to address effective QoS support, particularly for dynamic RPL networks.     

一种基于IPv6的物联网分布式源地址验证方案

作者在融合物联网的新一代互联网网络环境下,提出了基于IPv6的源地址验证整体架构.基于该架构,考虑物联网节点资源受限特点,并结合物联网末梢网络的拓扑形态及其路由方式上的特征,设计了基于IPv6的物联网末梢网络分布式源地址验证方案.分别讨论了静态指定、SLAAC(Stateless Address AutoConfiguration)、DHCPv6(Dynamic Host Configuration Protocol Version 6)以及DHCPv6与SLAAC混合情况下的物联网节点IP地址分配及其验证机制.模拟实验表明,该方案仅以微小的代价实现了物联网节点IP地址的分配,同时还保证了物联网节点之间、物联网节点与互联网端系统之间端到端通信时双方IP地址的真实可靠性,从而整体上增强了物联网的安全性.     

IRPL: An energy efficient routing protocol for wireless sensor networks

This study aims to overcome the disadvantages of the original RPL (IPv6 Routing Protocol for Low power and Lossy networks) routing protocol (RPL including problems with energy consumption and energy load balance). We developed a relatively balanced RPL – the improved protocol (IRPL). This protocol is based on an efficient clustering algorithm and an effective topology control model of the loop domain communication route. The clustering algorithm can be used to calculate the optimal number of cluster heads by assumption of the network model. Combined with the clustering probability model and the node competition mechanism, the cluster head node in the wireless sensor network was used to complete the clustering process. In the topology control model, the wireless sensor network was divided into concentric rings with equal areas. Nodes determined the best network route, depending on different levels of ring domain and the optimal forwarding communication area defined in this study. Simulation results indicate that the IRPL routing protocol can reduce overall network energy consumption, balance network energy consumption, and prolong network lifetime.     

无线传感器网络的RPL路由协议研究

路由协议执行网络拓扑描述、路由选择和数据包转发的功能,影响整个网络的性能和存活时间。现有的路由协议需要发送大量数据包维护网络拓扑,以及大量的存储空间来存储路由条目。由于硬件的限制,无线传感器节点无论是能量,还是其处理能力、存储能力都受到极大的制约。因此,IETFRoLL工作组提出了一种针对低功耗有损网络的IPV6路由协议,即RPL路由协议。文中对RPL路由协议的拓扑构建过程、数据包路由过程和Trickle定时器的算法等进行了分析,通过使用COOJA仿真工具对其进行仿真,验证了RPL路由协议在低功耗有损网络中具有较高的性能。     

Elastic Routing Table with Provable Performance for Congestion Control in DHT Networks

Consistent hashing-based DHT networks have an inherent load balancing problem. The problem becomes more severe in heterogeneous networks with nonuniform and time-varying popular files. Existing DHT load balancing algorithms are mainly focused on the issues caused by node heterogeneity. To deal with skewed lookups, this paper presents an elastic routing table (ERT) mechanism for query load balancing, based on the observation that high-degree nodes tend to receive more traffic load. The mechanism allows each node to have a routing table of variable size corresponding to node capacities. The indegree and outdegree of the routing table can also be adjusted dynamically in response to the change of file popularity and network churn. Theoretical analysis proves that the routing table degree is bounded. The ERT mechanism facilitates locality-aware randomized query forwarding to further improve lookup efficiency. By relating query forwarding to a supermarket customer service model, we prove that a two-way randomized query forwarding policy should lead to an exponential improvement in query processing time over random walking. Simulation results demonstrate the effectiveness of the ERT mechanism and its related query forwarding policy for congestion and query load balancing. In comparison with existing "virtual-server”-based load balancing algorithms and other routing table control approaches, the ERT-based congestion control protocol yields significant improvement in query lookup efficiency.     

一种针对RPL入侵检测的自适应节能算法

RPL（IPv6 routing protocol for low power and lossy networks）是IPv6低功耗有损无线网络的路由层协议,缺乏健全的安全保护机制且运行于资源受限的物联网设备导致容易受到网络攻击,因此在进行安全检测时应尽可能减少消耗设备资源。针对上述问题,分析了RPL网络的拓扑结构、RPL的入侵检测技术和常见网络攻击的原理,论证并提出了能够降低设备功率和网络负载的自适应节能算法,最后基于Contiki 3.0和Cooja实现并验证了该算法的有效性。实验结果表明,该算法能够根据网络拓扑挑选出有效的检测节点,在保证检测率的情况下降低约12%的设备平均功率。     

基于粒子群优化算法的RPL负载均衡研究

针对现有IPv6路由协议在建立网络拓扑过程中未考虑负载均衡,易导致低功耗有损网络出现部分节点能量过早耗尽、链路发生堵塞等问题,提出了一种基于父节点拥塞程度及其能量损耗的粒子群优化RPL路由协议(PSO-RPL)。通过将各子节点周围所有节点中Rank值最低的节点作为父节点集,并根据父节点集中所有节点的负载因子和剩余能量构造适应度函数的基础上,PSO-RPL借助粒子群优化算法获得了各子节点的最优父节点,从而实现了所有父节点的负载均衡。仿真结果表明提出的PSO-RPL协议实现了网络负载的有效均衡,延长了整个网络的生命周期,降低了整个网络的能量消耗。     

能量均衡的低功耗有损网络路由协议

针对目前低功耗有损网络路由协议（RPL）中存在节点能耗不均衡、网络生存时间短以及网络后期父节点状态信息更新不及时的问题,提出一种带有电量估算策略的能量均衡RPL（EB-RPL）。首先,构造了一种复合期望传输次数和节点剩余能量的路由度量,通过机制设计使节点在不同时期能自适应地调整网络拓扑;然后,设计了一种基于能量消耗速率的父节点电量估算策略,在不增加额外控制包开销的同时,子节点可以计算父节点电量,作出正确的路由决策;最后,通过实验对比分析了EB-RPL的性能。仿真结果显示,与RPL相比,EB-RPL显著降低了同级节点间功率标准差,并且在不同发包频率和网络规模中,分别平均延长了29.4%和39.4%的平均网络生存时间。EB-RPL能够有效实现能量均衡、显著延长网络生存时间。     

下一代全IP无线传感器网络路由方案

提出了无线传感器网络与IPv6网络全IP通信互联的路由方案。介绍了传感器节点的IPv6地址格式以及IPv6地址自动配置方案,基于所提出的IPv6地址格式,提出基于链路层的全IP传感器网络路由实现方案,同时采用侦听相邻节点下一次信道采样时间的方法提高路由效率以节省传感器网络功耗,并对实现路由方案的精简IPv6协议栈进行了详细的分析和讨论。分析了此方案的能量消耗以及数据延迟等性能参数,验证了此方案的有效性和正确性。     

Reconfigurable memory architecture for scalable IP forwarding engines

In this paper, a reconfigurable memory architecture and lookup technique for IP packet forwarding engines is presented. This is achieved by partitioning the forwarding table into smaller partial lookup tables for each output port and allowing a forwarding engine to process them in parallel. This effectively reduces the complexity of finding the ‘longest prefix match’ problem to the ‘first prefix match’ problem. Our method is a flexible technique that significantly elevates the scalability of the next generation network processors and other packet processing devices. Such scalability facilitates migration to IPv6 and benefits network equipments especially in terms of growing routing table size, traffic, frequency of route updates and bandwidth requirement.