802．11mesh网的研究及其安全分析

WMN（Wireless Mesh Network）是一种具有动态的无线多跳网状拓扑．自组织、自配置的无线接入网络。网络中各节点自动建立成一个Ad Hoc网络并保持一种网状连接。wMN具有前期投入低、系统容量大．维护简单,可靠性高等许多优点。而802．11mesh网则是802．11和mesh相结合的组网结构．其标准为IEEE802．11s．它使用一组网状的无线路由相连来提供一定区域的无线覆盖。正由于802．11 mesh网的这些特点．也带来了这种网络不同于传统802．11网络的一些新的安全挑战。本文给出了802．11mesh无线网状网的网络架构、关键技术,并重点研究了该网络的安全问题及其解决方案。     

802.11 mesh网的安全研究

WMN（wireless Mesh Network）是一种动态的自组织、自配置的网络。网络中的各节点自动建立成一个Adhoc网络并保持一种网状连接。WMN具有前期投入低、系统容量大、维护简单、可靠性高等许多优点。802．11mesh网是一种802．11和mesh相结合的组网结构，它使用一组网状的无线路由器相连来提供一定区域的无线覆盖。由于802．11mesh网的一些特点，这种网络也带来了一些不同于传统802．11网络的一些新的安全挑战。     

模块化无线mesh网络加密方案设计

文章在基于装有OpenWrt和Click的无线路由器所搭建的无线mesh网络测试床上,研究使用Click模块化路由编程工具,结合802.11i和802.11s草案针对无线mesh网络安全的协议设计方案,提出在无认证服务器环境中,使用预共享密钥进行数据包链路层加密以确保mesh节点间通信保密可靠的安全解决方案.     

改造无线路由器

随着IEEE正式批准通过了802．11n高速WLAN标准,越来越多的无线用户会选择基于802．11n标准的无线产品。那么,我们是否要扔掉旧的802．11g标准的无线产品呢？当然不!将旧的802．11g标准的无线路由器改造成无线AP,不仅能增大无线网络覆盖范围,还能提高802．11n网络的性能。     

IEEE802.11无线局域网标准的网络性能比较与分析

本文基于IEEE802．11标准，分析了802．11ab、g三大标准的特点及其实现的关键技术，并在频道数、传播范围、吞吐量、兼容性、传输速度和同频干扰等几方面，对不同标准网络进行了比较与分析，得出IEEE802．11网络在不同环境下使用的优缺点。最后，本文介绍了一种新的无线局域网应用方式：双频多模无线局域网。     

802．11b无线通信技术及其在工控网中的应用

介绍了工业控制网络的组成、结构及终端设备间的通信进程,提出了802．11b工业终端设备接入工控网的协议模型,分析了802．11b终端设备无线接入工控网的原理,探讨了工业控制网络中802．11b无线网关硬件和软件的实现方法。     

VCON发布HD5000和vPoint HD的新版本

近日，美国网件公司(NETGEAR)发布了基于Airgo公司TrueMIMOTM技术的新款MIMOG无线产品：MIMOG无线路由器(WGM124)和网卡(WGM511)。NETGEAR MIM0G无线路由器提供高达108Mbps的速度，极大地改善802．11b和802、11g网络性能，与802．11b、802．11g无线网络完全兼容，适应流媒体等高级的网络应用，为用户提供高性能的无线网络技术，     

IEEE802.11i无线局域网安全技术

介绍了当前无线局域网中的安全缺陷，分析了常见的无线局域网攻击手段，并在研究无线局域早期802．11标准安全缺陷的基础上重点分析了IEEE802．11i标准中的安全机制和关键技术。     

无线局域网标准IEEE802．11g的技术优势

无线局域网标准IEEE802．11g与其它IEEE802．11系列标准相比具有明显的技术优势。在2．4G频段使用正交频分复用(OFDM)调制技术，使数据传输速率提高到20Mbps以上；同时能够与应用广泛的802．11b共存在同一AP的网络里，保障了后向兼容性。本文着重介绍IEEE802．11g的技术优势。     

摩托罗拉LANPlanner：办助用户进行802—11n规划

随着802．11n的到来,无线局域网（WLAN）领域正在发生根本性的转变,而这场转变正如无线局域网的诞生一样引人瞩目。802．11n最终标准的极高数据速率为实现全无线企业网络奠定了坚实的基础。丰富的多媒体应用将无缝部署于网络内的各个节点,其卓越性能远远超过此前的802．11a／b／g技术。     

A Chemical Reaction Algorithm to Solve the Router Node Placement in Wireless Mesh Networks

Mobile Networks and Applications - This paper considers the problem of router node placement (WMN-RNP) in wireless mesh networks (WMN). A wireless mesh network consists of three kinds of nodes:...     

基于L-hop路由策略的无线mesh网络的吞吐量

无线mesh网络是最后一英里宽带互联网的可选技术之一。类似于ad hoe网络。在mesh网络中，每个用户节点既是通信终端又提供路由功能；用户节点以ad hoe多跳方式实现与网关的链接，通过网关可以访问因特网。无线mesh网络的吞吐量受到网关带宽的限制。为了捷高mesh网络网关频带的利用效率，现提出基于节点组织ad hoe通信方式和L-hop路由策略。在新的路由策略下，将给出对mesh网络的吞吐量的研究。     

软件路由器体系结构研究与设计

针对软件路由器特点,以Chick系统为基础,重新设计软件路由器,在设计过程中借助Chick体系结构的思想,尤其是在其体系结构规划、模块划分上,都尽量做到易于配置、管理和扩充。     

A flow-based network monitoring framework for wireless mesh networks

As an extension of wireless ad hoc and sensor networks, wireless mesh networks recently were developed as a key solution to provide high-quality multimedia services and applications, such as voice, data, and video, over wireless personal area networks, wireless local area networks, and wireless metropolitan area networks. A WMN has a hybrid network infrastructure with a backbone and an access network and usually is operated in both ad hoc and infrastructure modes with self-configuration and self-organization capabilities. In this article, we review security challenges, attacks, and countermeasures in the physical, medium access control (MAC), and network layers of wireless mesh backbone and access networks. We then extend the concept of traffic flow from IP networks and define meshflow in wireless mesh networks. Based on this new concept, we propose a comprehensive framework to realize network monitoring, user and router profiling, application and service balancing, and security protection in wireless mesh backbone networks. Practical issues and design trade-offs for implementing the proposed framework in real systems also are discussed.     

Asymptotic Capacity of Infrastructure Wireless Mesh Networks

An infrastructure wireless mesh network (WMN) is a hierarchical network consisting of mesh clients, mesh routers and gateways. Mesh routers constitute a wireless mesh backbone, to which mesh clients are connected as a star topology, and gateways are chosen among mesh routers providing Internet access. In this paper, the throughput capacity of infrastructure WMNs is studied. For such a network with Nc randomly distributed mesh clients, Nr regularly placed mesh routers and Ng gateways, assuming that each mesh router can transmit at W bits/s, the per-client throughput capacity has been derived as a function of Nc , Nr , Ng and W . The result illustrates that, in order to achieve high capacity performance, the number of mesh routers and the number of gateways must be properly chosen. It also reveals that an infrastructure WMN can achieve the same asymptotic throughput capacity as that of a hybrid ad hoc network by choosing only a small number of mesh routers as gateways. This property makes WMNs a very promising solution for future wireless networking.     

Mesh IP Video Surveillance Systems Model Design and Performance Evaluation

This paper proposes a model for Internet Protocol (IP) mesh video surveillance systems and presents the performance evaluation of Ah-hoc On-demand Distance Vector (AODV) and Open Shortest Path First (OSPF) routing protocols in wireless mesh video surveillance system. A wireless mesh video surveillance network consists of IP cameras linked to mesh routers which are then linked to the mesh gateways. Local monitoring can be done by inserting a switch or router between the gateways and the Internet while remote monitoring can be done through the Internet. Routing provides selection, constructing and management of routes in order to maximize throughput and minimize video packet losses, end-to-end delays and Jitter. Results show that the OSPF routing protocol outperformed the AODV in throughput, packet loss, end-to- end delay and Jitter terms with a throughput advantage of 35%.     

无线mesh网中一种基于博弈论的公平性路由协议

提出一种基于博弈论的以树为拓扑结构的公平性路由协议.新的协议综合了先验式路由和按需路由,并且将路由计算和信道资源分配控制分布到树中的每个枝节点上,降低了根节点的负担,使其更适合于无线 mesh网的通信需求.仿真结果表明,新的路由协议改进了AODV、HWMP路由协议的端到端平均延迟和网络吞吐量,并且网络中各个无线节点占有的信道资源基本相近,满足公平性原则.     

Mitigating the gateway bottleneck via transparent cooperative caching in wireless mesh networks

Wireless mesh networks (WMNs) have been proposed to provide cheap, easily deployable and robust Internet access. The dominant Internet-access traffic from clients causes a congestion bottleneck around the gateway, which can significantly limit the throughput of the WMN clients in accessing the Internet. In this paper, we present MeshCache, a transparent caching system for WMNs that exploits the locality in client Internet-access traffic to mitigate the bottleneck effect at the gateway, thereby improving client-perceived performance. MeshCache leverages the fact that a WMN typically spans a small geographic area and hence mesh routers are easily over-provisioned with CPU, memory, and disk storage, and extends the individual wireless mesh routers in a WMN with built-in content caching functionality. It then performs cooperative caching among the wireless mesh routers.We explore two architecture designs for MeshCache: (1) caching at every client access mesh router upon file download, and (2) caching at each mesh router along the route the Internet-access traffic travels, which requires breaking a single end-to-end transport connection into multiple single-hop transport connections along the route. We also leverage the abundant research results from cooperative web caching in the Internet in designing cache selection protocols for efficiently locating caches containing data objects for these two architectures. We further compare these two MeshCache designs with caching at the gateway router only.Through extensive simulations and evaluations using a prototype implementation on a testbed, we find that MeshCache can significantly improve the performance of client nodes in WMNs. In particular, our experiments with a Squid-based MeshCache implementation deployed on the MAP mesh network testbed with 15 routers show that compared to caching at the gateway only, the MeshCache architecture with hop-by-hop caching reduces the load at the gateway by 38%, improves the average client throughput by 170%, and increases the number of transfers that achieve a throughput greater than 1 Mbps by a factor of 3.     

基于电路交换的NoC路由器设计与实现

片上网络（Network-on-Chip, NoC）以网络互连结构代替传统总线结构,很好地解决了片上高性能计算资源之间的通信瓶颈问题。路由器是实现NoC的重要基础部件,本文在分析国内外相关技术的基础上,面向无线通信等要求有保障服务的应用,设计并实现了一个基于电路交换的路由器。该路由器适合Mesh结构,提供5个输入输出端口,支持容量达48Gbit／s的交换,可以提供100％的无阻塞交换能力,并可配置为多播和广播方式。采用Verilog语言完成了所有设计工作,不仅进行了充分的仿真和验证,还使用Altera的FPGA实现了该设计,能够满足片内通信的需要。     

A robust security scheme for wireless mesh enterprise networks

In this paper, we address the security challenges for wireless mesh enterprise networks (WMENs). The topology and communication characteristics of WMEN include the following: (a) deployment of the network devices are not planar, rather, devices are deployed over three-dimensional space (e.g., office buildings, shopping malls, grocery stores, etc.); (b) messages, generated/received by a mesh client, traverse through mesh routers in a multihop fashion; and (c) mesh clients, being mostly mobile in nature, may result in misbehaving or be spurious during communications. We propose a security scheme for WMEN in order to ensure that only authorized users are granted network access. Particularly, our scheme includes: (a) a deterministic key distribution technique that perfectly suits the network topology, (b) an efficient session key establishment protocol to achieve the client–router and router–router communications security, and (c) a distributed detection mechanism to identify malicious clients in the network. Analytical and simulation results are presented to verify our proposed solutions.