内容推送和路由扩散相结合的内容源移动管理优化方案

在内容中心网络(Content Centric Networking,CCN)中,消费者请求按照原有转发路径无法成功交付移动内容源,兴趣包丢失率高;为保证移动内容源的可达性,则需要对全网路由器进行路由更新,这将造成巨大的更新开销.针对上述问题,提出内容推送和路由扩散相结合的内容源移动管理优化方案.与现有CCN内容源移动...     

Energy efficient fault-tolerant multipath routing scheme for wireless sensor networks

In wireless sensor network （MSN）, reliability is the main issue to design any routing technique. To design a comprehensive reliable wireless sensor network, it is essential to consider node failure and energy constrain as inevitable phenomena. In this paper we present energy efficient node fault diagnosis and recovery for wireless sensor networks referred as energy efficient fault tolerant multipath routing scheme for wireless sensor network. The scheme is based on multipath data routing. One shortest path is used for main data routing in our scheme and other two backup paths are used as alternative path for faulty network and to handle the overloaded traffic on main channel. Shortest pat data routing ensures energy efficient data routing. Extensive simulation results have revealed that the performance of the proposed scheme is energy efficient and can tolerates more than 60% of fault.     

CCN中基于替换率的缓存空间动态借调机制

针对内容中心网络(CCN, content centric networking)节点存储资源的有效利用和优化配给问题,在同质化缓存分配的基础上,提出了一种基于替换率的缓存空间动态借调机制。该机制从节点存储空间使用状态的动态差异性出发,首先对于缓存资源借调的合理性给予证明,进而,依据节点对于存储资源的需求程度,动态地执行缓存借调,将相对空闲的存储资源分配给需求程度更大的节点支配,换取过载节点缓存性能的提升。该机制减小了内容请求跳数,提高了缓存命中率,以少量额外的代价换取了内容请求开销的显著下降,提升了存储资源整体利用率,仿真结果验证了其有效性。     

Multipath inter-domain routing for named data networking

To facilitate content retrieval among NDN domains,a multipath inter-domain routing for named data networking(MIRNDN)was proposed.Under MIRNDN,an AS(autonomous system)maintained merely the routing state of content reachable from its own network or from its customers’ networks and aggregated routing information to mitigate routing scalability issue; “valley free”routing policy was applied to guide Interest packets that solicit content unreachable from the AS’s own network nor from its customers’ networks to explore matching data packets via multiple paths,and NDN’s requests aggregation,in-network caching and adaptive forwarding optimized such exploration; the reachability information of content from multiple paths was collected to support Interest multipath forwarding.The properties of FIB size and the convergence time and communication cost of routing update under MIRNDN were analyzed in theory.The experimental results in the AS level topology of current Internet validates that MIRNDN mitigates the scalability issue of NDN inter-domain routing,has relative short convergence time and moderate communication cost for routing update,and effectively reduces unnecessary Interest forwarding.     

Modeling chunk-based content placement in information centric networking

Content-centric networking (CCN) proposes a content-centric paradigm which changes the waist hourglass from Internet protocol (IP) to content chunk. In this paper, based on content chunks, an optimization model of minimizing the total delay time in information centric networking (ICN) is established, and branch-and-bound method and greedy (BG) algorithm is proposed to get the content placement method. As the multipath is natural supported in CCN, chunk-based content placement can decline delay time obviously, even it would increase the calculation amount which can be solved easily by the node's capacity. Simulation results indicate that the chunk-based content placement scheme is better than the single-based cache policy on the network total delay time, and the best number of each content chunk split is decided by the link density and the number of the nodes in the network.     

内容中心网络缓存隐私保护策略

缓存隐私泄露是内容中心网络中的重要安全威胁之一,攻击者通过探测缓存可以获取合法用户的隐私信息。针对该安全问题,在隐私与非隐私内容区分的基础上,提出一种基于最近访问信息与回退机制的缓存隐私保护策略（CPPS-RVI&ECP）,并与现有典型防御策略-随机k延迟（RFKD）对比,围绕隐私泄露率与网络命中率开展理论性能分析。该策略通过设置隐私标识,实现最近访问者的识别;通过随机缓存位置存入以及移出回退机制,降低了隐私泄露概率,且提升了网络性能。设定实验条件进行数值分析,结果表明,虽然RFKD有理想的隐私保护能力,但是它是以完全牺牲缓存的内容分发能力为代价的,而CPPS-RVI&ECP则通过合理设置回退概率,可以在保持较低隐私泄露率的同时,获得较高的网络命中率。     

基于双信道的一种ad hoc网络路由策略

利用多个信道接口来改善ad hoc网络信道容量。即一个信道周期性的广播节点状态信息分组来维护全网所有节点的状态信息，而另一个信道利用此信息采用最短路径搜寻算法来获得到目的节点的路由并完成数据传输。这样充分结合了表驱动路由方法和按需式路由方法的优点。另外，信息维护与数据分组分别在两个信道内同时进行，避免了信息维护对数据分组传输的影响，提高了网络性能。     

Zebra与BGP路由监测的实现

主要研究边界网关协议（BGP）网络拓扑动态重构及网络稳定性。通过路由软件Zebra实现一个具有部分路由器功能的监测代理,并将其连接到网络中一台BGP边界路由器,通过它们之间的BGP协议交互,监测代理可捕获到整个网络的路由信息,并籍此进行BGP路由监测。     

基于收益感知的信息中心网络缓存机制

针对信息中心网络（ICN）内置缓存系统中的海量内容块流行度获取和存储资源高效利用问题,以最大化节省内容访问总代价为目标,建立针对内容块流行度的缓存收益优化模型,提出了一种基于收益感知的缓存机制。该机制利用缓存对请求流的过滤效应,在最大化单点缓存收益的同时潜在地实现节点间协作和多样化缓存;使用基于布隆过滤器的滑动窗口策略,在检测请求到达间隔时间的同时兼顾从源服务器获取内容的代价,捕获缓存收益高的内容块。分析表明,该方法能够大幅压缩获取内容流行度的存储空间开销;仿真结果表明,该方法能够较为准确地实现基于流行度的缓存收益感知,且在内容流行度动态变化的情况下,在带宽节省和缓存命中率方面更具优势。     

基于位置无关名字的可扩展几何路由方案

名字路由已成为未来网络的研究热点之一,由于网络中节点和信息规模的持续增长,可扩展问题成为其瓶颈.几何路由作为新型可扩展路由方案,可同时满足路由表规模和路由路径的可扩展,但难以支持名字路由.首先在几何路由基础上提出了一种通用的基于位置无关名字的可扩展几何路由方案——GRIN,结合源路由和贪心路由实现混合几何路由,在混合几何路由上引入基于双层稀疏群组的名字解析(映射).然后理论分析了节点状态及名字映射的路径延展度上界.最后通过仿真验证了GRIN具备可扩展、低延展度以及高可靠性等特征,并优于其他名字路由方案.     

车联网场景下基于内容中心网络的优化缓存策略

车联网中,如何有效选择缓存位置和缓存内容对于提高整体网络性能至关重要。针对上述问题,引入了内容中心网络技术,提出了一种新的优化缓存策略——缓存位置和缓存内容的选择取决于车辆节点值和内容流行度(Vehicle Node Value and Content Popularity,VNVCP)。首先,定义了连通性、中间中心性和特征向量中心性3个车辆节点属性用来评估车辆节点的值,具有不同值的车辆节点缓存具有不同流行度的内容,内容的重要性由其受欢迎程度决定。其次,该策略利用不同类型内容受欢迎程度的差异确保缓存内容分布均匀,同时评估来自多个属性的车辆节点的值以提高车辆节点利用率。仿真结果表明,VNVCP在缓存命中率、平均跳数和传输延迟方面明显优于传统的LCE(Leave Copy Every where)、Prob(0.5)和MPC(Most Popular Content)。     

WCDS‐DCR: an energy‐efficient data‐centric routing scheme for wireless sensor networks

Wireless sensor networks (WSNs) typically consist of a large number of battery‐constrained sensors often deployed in harsh environments with little to no human control, thereby necessitating scalable and energy‐efficient techniques. This paper proposes a scalable and energy‐efficient routing scheme, called WCDS‐DCR, suitable for these WSNs. WCDS‐DCR is a fully distributed, data‐centric, routing technique that makes use of an underlying clustering structure induced by the construction of WCDS (Weakly Connected Dominating Set) to prolong network lifetime. It aims at extending network lifetime through the use of data aggregation (based on the elimination of redundant data packets) by some particular nodes. It also utilizes both the energy availability information and the distances (in number of hops) from sensors to the sink in order to make hop‐by‐hop, energy‐aware, routing decisions. Simulation results show that our solution is scalable, and outperforms existing schemes in terms of network lifetime. Copyright © 2010 John Wiley & Sons, Ltd.     

Traffic scheduling method based on segment routing in software-defined networking

In order to address the multi-commodity flow problem for traffic scheduling in software-defined networking,a method based on segment routing was proposed.The proposed method pre-computed sets of candidate paths and attributes of these paths for all source-target nodes,and set the requirements of attributes of candidate paths that should be met combined with various demands and constraints of flows,then generated sets of candidate paths for flows.In the proposed scheme,multi-commodity flow model in software-defined networking was simplified based on sets of candidate paths for flows,the difficulty of solving was reduced,the centralized control by the controller and the autonomous control by nodes were supported,the scalability of controller was improved.In addition,how to meet the energy-saving needs of the network was proposed,i.e.,reducing the number of links that could participate in flow forwarding.The performance evaluation results indicate that the proposed method can meet various demands and constraints of flows,improve network performance,and reduce the computational load of solving the problem of traffic scheduling.     

Novel multi-path routing scheme for UWB Ad hoc network

1 Introduction Ad hoc networks and ultra-wideband communications technology are a key factor in the evolution of wireless communications. In ad hoc networks, wireless hosts can communications with each other in the absence of a fixed infrastructure. These networks typically consist of equal nodes that communication over wireless links without central control .The followings can be used to describe the ad hoc network[1]: ? Dynamic network topology ? Limited resource ? Multi-hop communication …     

Valiant load-balancing and regionalized routing scheme

Valiant load-balancing(VLB)routing scheme has drawbacks of logical full mesh,intermediate nodes(networks)and single application of topology.To address these,the authors propose a novel routing scheme called regionalized VLB(R-VLB).Based on ideas of VLB and regionalizing,R-VLB divides the nodes of backbone network into several regions whose topological structure is logical full mesh,and combines shortest-path routing scheme and VLB routing scheme.R-VLB also achieves logical local interconnection,non-central nodes(networks)and a wide range of application of topology.The relevant theoretical analysis and simulation results show that R-VLB achieve good throughput and failure performance close to that of VLB,and it even has better delay performance.R-VLB provides an idea for the application of VLB routing scheme.     

Throughput oriented forwarders selection analysis for opportunistic routing in wireless mesh network

Opportunistic routing explicitly takes advantage of the broadcast nature of wireless communications by using a set of forwarders to opportunistically perform packet forwarding. A key issue in the design of opportunistic routing protocols is the forwarder list selection problem. This paper proposes a novel routing metric which shows the end-to-end throughput and a corresponding throughput oriented opportunistic routing forwarder-selecting algorithm throughput oriented forwarders selection (TOFS) through analyzing forwarding characteristics of forwarders. The algorithm puts forward a constraint mechanism that controls the number of forwarders by constraint of throughput for forwarders selection, achieving a better balance between number of forwarders and effective link stability by introducing the factor of transmission time. Simulation results show that the algorithm can improve the network end-to-end throughput effectively over existing methods.     

Push applications and dynamic content generation over content‐centric networking

Content‐Centric Networking (CCN) represents an established candidate for the future Internet, proposing a routing architecture designed to elevate content to first class entity. Starting from the fact that the network usage has dramatically evolved towards content retrieval, CCN relies on an on‐demand pull based mechanism to transfer data from the different sources to the heterogeneous consumers. This paradigm enhances the network in a number of ways, ranging from the newly introduced in‐network caching capabilities to the benefits provided by the symmetric data routing adopted by CCN. In this renewed network scenario, we place our attention to those applications that do not perfectly fit the pull paradigm, stating that they need to be supported as well and proposing an effective way to achieve scalability on large scale push applications. We provide the following contributions: (i) we identify the functions that a data‐centric architecture should support; (ii) propose and compare our solution with the state of the art framework designed for the specific problem of pushing data to content requesters; and (iii) evaluate their performance in terms of traffic generated and scalability achieved by simulating a real Internet Service Provider (ISP) topology and the realistic workload of a generic social network application. Copyright © 2015 John Wiley & Sons, Ltd.     

Quantified Cost-Balanced routing scheme for overlay multicast

This paper focuses on the quantitative analysis issue of the routing metrics tradeoff problem, and presents a Quantified Cost-Balanced overlay multicast routing scheme （QCost-Balanced） to the metric tradeoff problem between overlay path delay and access bandwidth at Multicast Server Nodes （MSN） for real-time applications over Internet. Besides implementing a dynamic priority to MSNs by weighing the size of its service clients for better efficiency, QCost-Balanced tradeoffs these two metrics by a unified tradeoff metric based on quantitative analysis. Simulation experiments demonstrate that the scheme achieves a better tradeoff gain in both two metrics, and effective performance in metric quantitative control.     

对一种混合结构洋葱路由方案的密码学分析

对时金桥等提出的混合结构洋葱路由方案进行了分析,发现存在的安全漏洞。第一个漏洞来源于其密码学报文结构的可展性。攻击者能够利用该漏洞改变洋葱消息的路由或在其中嵌入标签以追踪消息路由。另一个漏洞表现在匿名转发服务器容易遭受选择密文攻击。展示了3种不同的能够以较低代价破坏发送者和接收者不可关联性的攻击过程。为了避免所提到的攻击,提出了能够利用反向调查捕获恶意节点的修正方案。     

单级号码分析表在移动软交换中的应用

号码分析表是程控交换机根据路由代码映射到具体局向时所需要使用的数据。目前号码分析表主要有两种构成方法:单级表和多级表,一般认为单级号码分析表已经不适应当今交换技术的发展。文章结合移动通信的特点和发展趋势,并结合仿真结果进行分析,对两种路由表在时间和空间上的优缺点进行了对比,验证了在局向配置较少的交换局中使用单级号码分析表的可行性和优点。