校园局域网建设实例分析

随着计算机网络时代的飞速发展,局域网的建设是企业单位发展普及的趋向,因为局域网给人们带来很多优势。局域网的建设根据要求不同,所需的费用也不一样,小至家庭,大至企事业单位,都可以组建。随着中国社会的发展,企业也越来越多,局域网建设也越来越多。在未来即将普及的局域网,更多使用计算机的人懂得局域网知识也是形势所趋,无论在建设、使用、维护等方面都能提供一定的帮助。局域网建设过程涉及到各种网络技术和实施方案等方面知识,现以我校的校园局域网建设为例,谈谈局域网的建设。

RACF体系架构的局域网网关控制研究

首先详细介绍了RACF体系架构,接着介绍了局域网网络设备的QoS能力,然后分析了现有的RACF体系架构对局域网网关控制的不足,提出了基于RACF体系架构的局域网网关控制,并给出了具体的结构图和控制流程。

企业局域网的建设与维护

随着时代的不断发展，科技的不断变迁，计算机技术和网络的应用得到了普及。尤其是以企业的局域网尤为明显，有效的企业局域网的建设和维护可以为企业带来更好的发展。因此，一套有效的、安全的、科学的企业局域网建设方案是必不可少的，本文就企业局域网的建设与维护进行探讨，以期可以得到有效的、安全的、科学的企业局域网建设的方案，使得企业的局域网建设和维护能够得到进一步的发展。

局域网与广域网结合的安全生产监管系统

结合了局域网与广域网两种网络各自的优点并用于安全生产监督管理网络体系的建设,形成了以区县级安全生产监督管理局为主,街道、社区安监办为辅,两者协调工作的安全生产监督管理网络模式,既提高了区县级安监局的工作效率,也充分发挥了街道、社区安监办在安全生产管理中的积极作用。

VNN环境下的卫星电视广域网接收

电视局域网广播技术已经比较成熟,因为受到本地局域网网关和防火墙等种种限制,使得广域网卫星电视直播难以实现。因此在广域网中如何共享接卫星电视,是卫视接收的一个新思路。本文利用VNN虚拟网技术,比较好的实现了广域网卫星电视直播。我国是经济不发达的国家,特别在西部地区教育资源相对匮乏,利用直播卫星开展远程教育,在投资较少的情况下共享师资资源,充分发挥发达城市资源优势。

浅谈医院外网ARP攻击及解决方法

通过对ARP攻击原理分析,使用软路由解决医院外网局域网断网故障。

Arp协议在校园网管理中的探索

近期借助arp协议实施破坏网络安全应用的问题特别突出,互联网上出现了许多基于arp开发的病毒或恶意程序。由于受到基于ARP病毒攻击的危害,全国大中院校的校园网,网络故障频繁发作。网络病毒发作特征表现为:用户使用网络时会突然掉线,过一段时间后又会恢复正常,用户频繁断网,IE浏览器频繁出错,以及一些常用软件出现故障等,部分基于arp的木马除了会导致用户上网出现时断时续的现象外,还窃取用户密码。如盗取QQ密码、网上银行账号及密码等,给用户造成了很大的不便和巨大的经济损失。

Performance enhancement of IEEE 802.11 distributed coordination function for MANET

The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC.

Generation of scale-free knowledge network with local world mechanism

In order to simulate the real growing process, a new type of knowledge network growth mechanism based on local world connectivity is constructed. By the mean-field method, theoretical prediction of the degree distribution of the knowledge network is given, which is verified by Matlab simulations. When the new added node＇s local world size is very small, the degree distribution of the knowledge network approximately has the property of scale-free. When the new added node＇s local world size is not very small, the degree distribution transforms from pure power-law to the power-law with an exponential tailing. And the scale-free index increases as the number of new added edges decreases and the tunable parameters increase. Finally, comparisons of some knowledge indices in knowledge networks generated by the local world mechanism and the global mechanism are given. In the long run, compared with the global mechanism, the local world mechanism leads the average knowledge levels to slower growth and brings homogenous phenomena.

Cascading failures in local-world evolving networks

The local-world (LW) evolving network model shows a transition for the degree distribution between the exponential and power-law distributions, depending on the LW size. Cascading failures under intentional attacks in LW network models with different LW sizes were investigated using the cascading failures load model. We found that the LW size has a significant impact on the network's robustness against deliberate attacks. It is much easier to trigger cascading failures in LW evolving networks with a larger LW size. Therefore, to avoid cascading failures in real networks with local preferential attachment such as the Internet, the World Trade Web and the multi-agent system, the LW size should be as small as possible.

Joint User Association and Resource Allocation for Self-Backhaul Ultra-Dense Networks

In order to meet the exponentially increasing demand on mobile data traffic, self-backhaul ultra-dense networks(UDNs) combined with millimeter wave(mm Wave) communications are expected to provide high spatial multiplexing gain and wide bandwidths for multi-gigabit peak data rates. In selfbackhaul UDNs, how to make the radio access rates of small cells match their backhaul rates by user association and how to dynamically allocate bandwidth for the access links and backhaul links to balance two-hop link resources are two key problems on improving the overall throughputs. Based on this, a joint scheme of user association and resource allocation is proposed in self-backhaul ultra-dense networks. Because of the combinatorial and nonconvex features of the original optimization problem, it has been divided into two subproblems. Firstly, to make the radio access rates of small base stations match their backhaul rates and maximize sum access rates per Hz of all small cells, a proportional constraint is introduced, and immune optimization algorithm(IOA) is adopted to optimize the association indicator variables and the boresight angles of between users and base stations. Then, the optimal backhaul and access bandwidths are calculated by differentiating the general expression of overall throughput. Simulation results indicatethat the proposed scheme increases the overall throughputs significantly compared to the traditional minimum-distance based association scheme.

AN MAC PROTOCOL SUPPORTING MULTIPLE TRAFFIC OVER MOBILE AD HOC NETWORKS

This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks. The dynamic channel selection scheme by receiver decision is implemented and the number of the data channel is independent of the network topology. The priority for real-time traffic is assured by the proposed adaptive back off algorithm and different IFS. The protocol is evaluated by simulation and the results have shown that it can support multiple traffics and the performance is better than the performance that IEEE 802.11 standard provides.

An Indoor Ubiquitous Computing Environment Based on Location-awareness

To provide the right services or information to the right users, at the right time and in the right place in ubiquitous computing environment, an Indoor Ubiquitous Computing Environment based on Location-Awareness, IUCELA, is presented in this paper. A general architecture of IUCELA is designed to connect multiple sensing devices with locationaware applications. Then the function of location-aware middleware which is the core componnet of the proposed architecture is elaborated. Finally an indoor forum is taken as an example scenario to demonstrate the security, usefulness, flexibiltity and robustness of IUCELA.

Secure Authentication of WLAN Based on Elliptic Curve Cryptosystem

The security of wireless local area network （WI.AN） becomes a bottleneck for its further applications. At present, many standard organizations and manufacturers of WLAN try to solve this problem. However, owing to the serious secure leak in IEEES02.11 standards, it is impossible to utterly solve the problem by simply adding some remedies. Based on the analysis on the security mechanism of WLAN and the latest techniques of WI.AN security, a solution to WLAN security was presented. The solution makes preparation for the further combination of WLAN and Internet.

MOBILITY AIDED LOCALIZATION OF WIRELESS SENSOR NETWORKS WITH INACCURATE RANGE MEASUREMENTS

This paper studies the relationship between mobility, navigation and localization in the context of wireless sensor networks with mobile beacons. It is observed that mobility can aid in network node localization and that once localized, the network nodes can localize and track a mobile object and guide its navigation. A distributed kernel-based algorithm is proposed that enables the nodes to establish confident position estimates in the presence of ranging inaccuracies. The proposed approach features robustness with respect to range measurement inaccuracies, low complexity and distributed implementation, using only local information. Simulation validates our approach viable.

PLANNING DESIGN OF COMPUTER REGION NETWORK

In this paper, authors describe the characters and the present situation of computer region network, Moreover, authors put forward the method to plan and de sign ration ally the computer regional network system depending on the actual situa tion, in order to share the resources of software and hardware resources of the net work in best way and get higher efficiency of information management.

NASSN:a NAS-based storage network

With the digital information and application requirement on the Internet increasing fleetly nowadays,it is urgent to work out a network storage system with a large capacity,a high availability and scalability.To solve the above-mentioned issues,a NAS-based storage network(for short NASSN)has been designed.Firstly,the NASSN integrates multi-NAS,iNAS(an iSCSI-based NAS)and enterprise SAN with the help of storage virtualization,which can provide a greater capacity and better scalability.Secondly,the NASSN can provide high availability with the help of server and storage subsystem redundancy technologies.Thirdly,the NASSN simultaneously serves for both the file I/O and the block I/O with the help of an iSCSI module,which has the advantages of NAS and SAN.Finally,the NASSN can provide higher I/O speed by a high network-attached channel which implements the direct data transfer between the storage device and client.In the experiments,the NASSN has ultra-high-throughput for both of the file I/O requests and the block I/O requests.

A Performance Comparison of Two Real Time WLAN MAC Protocols

By modifying the IEEE 802.11 wireless local area network(WLAN) medium access protocol(MAC),a contention based and a polling based protocol are proposed to deal with the case every station possesses two classes of frame in real time applications.Both protocols can ensure the real time frame only need to wait a determinable bounded time.These two protocols are introduced briefly and a performance comparison between them is made.Simulation results show that each protocol has advantage over the others in certain network condition.

WLAN indoor location method based on artificial neural networkt

WLAN mdoor location method based on artificial neural network （ANN） is analyzed. A three layer feed-forward ANN model offers the benefits of reducing time cost of the layout of an indoor location system, saving storage cost of the radio map establishment and enhancing real-time capacity in the on-line phase. According to the analysis of SNR distributions of recorded beacon signal samples and discussion about the multi-mode phenomenon, the one map method is proposed for the purpose of simplifying ANN input values and increasing location performances. Based on the simulations and comparison analysis with other two typical indoor location methods, K-nearest neighbor （KNN） and probability, the feasibility and effectiveness of ANN-based indoor location method are verified with average location error of 2.37m and location accuracy of 78.6% in 3m.

Digital Solution to Mining Image Monitor System

The thesis describes an advanced digital solution to mining digital image monitor system, which makes up the shortage of the traditional mining analog image monitor. It illustrates the system components and how to choose the encoder bandwidth of the system. The problem of image multicast and its solution in LAN are also discussed.