一种新的主动节点资源访问控制策略

较传统网络而言,主动网络的复杂性引起了更加严峻的资源安全问题,特别在主动节点方面.文章详细分析了主动节点资源访问的研究现状和存在的问题,设计了主动节点资源访问安全体系,提出了一种新的主动节点资源访问控制机制.并提出利用权能对资源访问控制策略进行描述,动态维护.采用基于角色的访问控制方法实现对用户的管理.     

基于J-sim的主动结点资源访问控制策略实现

在主动节点资源访问控制上,设计了一种新的主动节点资源访问控制机制.提出利用权能对资源访问控制策略进行描述,动态维护.对用户的管理采用基于角色的方法.在主动信包中封装用户角色信息,主动节点解析出用户角色后,依据它在策略库中匹配相应的描述控制访问权限策略的方法,即权能.通过权能实现对节点资源的访问.并通过仿真试验验证了算法的有效性.     

主动网络及其主要项目介绍

主动网络是一种新型的网络体系结构，他可以根据网络应用和服务的要求，对网络进行编程，因而大大加快了网络新应用和新服务的实施，适应了网络快速发展的需要。文章系统剖析了主动网络中主动节点的体系结构，并阐述了主动网络的几个主要项目。     

基于拍卖的P2P内容分发网络带宽分配机制

为了解决P2P内容分发网络中带宽资源稀缺且分配不合理这一突出问题,抑制节点的自私性行为,设计了一种基于拍卖的带宽分配机制。该机制通过上载带宽支付方式,迫使自私请求节点选择合适的带宽需求,使得整个P2P网络中的节点良性竞争带宽资源,避免了"公共地悲剧"的发生;且带宽分配算法在资源节点和请求节点并行执行,能很好适应P2P网络的分布式特性。仿真结果表明,该机制能够有效遏制搭便车行为,从而缩短P2P内容分发的平均完成时间,降低内容源服务器的上传数据比例。     

一种新的主动网络安全体系的设计

尽管主动网络原型系统中设计了一些安全措施，但是它们都不具通用性且主要集中在security方面，这在主动网络必须和传统网络相兼容的情况下，阻碍了主动网络的发展。本文在定义消极型错误和积极型错误的基础上，设计了主动网络资源控制核。然后提出了集security和safety保障为一体的基于资源控制核的一种通用的主动网络安全体系，探讨了该体系应具有的特点、设计目标和可行性，并设计了主动节点的安全机制。     

主动网络的研究

主动网络是一种新型的可编程分组交换网络,它使网络节点具有计算能力,改变了传统的IP网工作模式,将被动的“存储-转发”机制转变为主动的“存储-计算-转发”机制。全面系统地介绍了主动网络的体系结构、运行机制,主动网络的发展状况及所面临的有关问题,可解决当前Internet所遇问题,展示了网络研究发展的新方向。     

主动网络信包验证和代码授权机制研究

本文提出了运用认证和授权方式来解决主动网络所面临的安全问题，利用X509证书、数字签名、jaVa语言安全以及Java认证和授权服务等实现了一个主动网络的信包认证和代码授权机制，并在原主动信包的基础上设计了安全主动信包。其中，信包验证包括了对主动信包的身份认证和完整性验证，主要是为了解决非法节点向主动节点发送恶意代码或者中途篡改主动信包的问题；代码授权包括了对EE代码的授权和对主动信包代码的授权，通过限制外来代码在主动节点上的活动来避免其对主动节点造成危害性后果。     

主动网络技术及其应用

介绍了主动网络技术的基本原理、主动网络的几种执行环境机制,例举了一种面向服务内容的可编程路由主动网络的实际应用,并描述了主动网络节点的基本工作过程.     

主动网络技术在MPLS-VPN中的应用研究

利用主动网络的可编程性,文中提出一种将主动网络技术运用于MPLS-VPN网络中的方案,通过将网络管理程序动态部署到各主动节点上,实现了网络的智能化、分布式管理。同时,可根据用户的需求,调用主动节点中相关的主动代码,动态配置业务执行环境,满足用户对QoS的要求。     

Review on Dynamic Bandwidth Allocation of GPON and EPON

The passive optical network (PON) technology has been drastically improved in recent years. In spite of using the optical technology, the utilization of the entire bandwidth is a very challenging task. The main categories of PON are the Ethernet passive optical network (EPON) and gigabit passive optical network (GPON). These two networks use the dynamic bandwidth allocation (DBA) algorithm to attain the maximum usage of bandwidth, which is provided in the network dynamically according to the need of the customers with the support of the service level agreement (SLA). This paper will provide a clear review about the DBA algorithm of both technologies as well as the comparison.     

Resources Management in Active Networks

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Ethernet PONs: a survey of dynamic bandwidth allocation (DBA) algorithms

Optical networks are poised to dominate the access network space in coming years. Ethernet passive optical networks, which leverage the ubiquity of Ethernet at subscriber locations, seem destined for success in the optical access network. In this article we first provide a brief introduction to Ethernet passive optical networks, followed by a discussion of the problem of dynamic bandwidth allocation. We then introduce a framework for classifying dynamic bandwidth allocation schemes and provide a comprehensive survey of the dynamic bandwidth allocation methods proposed to date. We conclude with a side by side comparison of the schemes based on their most prominent characteristics, and outline future developments of dynamic bandwidth allocation schemes.     

Active RC Synthesis for Significant Reduction in Magnitudes of Reactive Elements

Low impedance levels and/or large system time constants lead to network realizations with large total reactance values in ordinary passive and active RC synthesis. It is shown how active RC networks may, instead, be designed, in which one may freely a priori specify the total capacitance and the input and output resistances. The basic design philosophy is to assign relatively faroff poles to the passive part of the system. Feedback is used to obtain the desired close-in (large time constant) system poles. In one method, employing a single negative-impedance-converter, any number of system poles may be simultaneously realized. However, the output is very sensitive to variations in active and passive parameter values. Also, the negative-impedance-converter must act as such over the bandwidth of the passive part of the network, which part is much larger than that of the system as a whole. A second approach is far more practical. It employs a cascade of isolated canonic second-order structures, each of which realizes a pair of system poles. The resulting design is much less sensitive to active and passive parameter variations, and is much easier to tune. The structure used is especially suitable for narrow-band filtering. Also, the active element bandwidth need only be of the same order of magnitude as that of the system poles. Design relations are developed and optimized with respect to a figure of merit ASA, being the product of amplifier gain required and system sansitivity to amplifier gain variations.     

基于方程相容性检测有源网络多重故障的可测性

该文引入零泛器电路讨论有源网络的k故障定位的问题,使含有四种受控电源的有源网络k故障定位方法与无源网络统一起来。此外,对有源网络k故障定位的局部可测条件和全局可测条件从拓扑上进行了分析。     

Fair queueing with service envelopes (FQSE): a cousin-fair hierarchical scheduler for subscriber access networks

In this paper, we propose and investigate the characteristics of a fair queueing with service envelopes (FQSE) algorithm-a hierarchical fair-share scheduling algorithm for access networks based on a remote scheduling system such as Ethernet passive optical networks (EPON) or cable TV network. FQSE is designed to overcome the limiting factors of a typical remote scheduling system such as large control-plane delay, limited control-plane bandwidth, and significant queue switch-over overhead. The algorithm is based on a concept of service envelope-a function representing the fair allocation of resources based on a global network condition called satisfiability parameter (SP). We define properties of cousin-fairness and sibling-fairness and show the FQSE to be cousin-fair. FQSE is unique in that it is the only hierarchical algorithm that is simultaneously cousin-fair. Furthermore, we show the necessary techniques to adapt FQSE to variable-sized packet-based networks. We analyze FQSE performance in EPON serving 1024 independent queues and demonstrate FQSE's ability to provide guaranteed bandwidth to each queue and to share the excess bandwidth fairly.     

Inter‐ONU Bandwidth Scheduling by Using Threshold Reporting and Adaptive Polling for QoS in EPONs

I dynamic bandwidth allocation (DBA) scheme, an inter–optical network unit (ONU) bandwidth scheduling, is presented to provide quality of service (QoS) to different classes of packets in Ethernet passive optical networks (EPONs). This scheme, referred to as TADBA, is based on efficient threshold reporting from, and adaptive polling order rearranging of, ONUs. It has been shown that the network resources are efficiently allocated among the three traffic classes by guaranteeing the requested QoS, adaptively rearranging the polling orders, and avoiding nearly all fragmentation losses. Simulation results using an OPNET network simulator show that TADBA performs well in comparison to the available allocation scheme for the given parameters, such as packet delay and channel utilization.     

EPON系统的动态带宽分配算法的研究

在未来几年里，光网络已经为主宰接入网领域做好了准备。首先简单介绍了以太网无源光网络以及目前已经提出的不同的动态带宽分配算法，然后针对每个算法不同的特点与适用范围进行了性能分析和比较，最后对动态带宽算法未来的发展进行了展望。     

一种在EPON中快速面向包调度的服务分级机制

当今,EPON中的动态带宽分配(DBA)机制已经得到了广泛的研究.然而,很多这样的机制仍然不能在给用户提供公平稳定的服务的同时也提高网络的利用效率.现提出了一种新的基于OLT的带宽分配的模型,其使用了credit容器技术.根据不同的服务级别分配网络带宽.     

A framework for resource dimensioning in GPON access networks

In gigabit passive optical networks (GPONs), the ports of the optical line terminal (OLT) support passive optical networks (PONs). An optical split ratio supported on an OLT chassis determines the number of optical network units (ONUs) which can share PON link capacity. Generally, network planners tend to do dimensioning for PON link capacity (OLT port) based on the number of subscribers and their type (i.e. residential or business). Although this dimensioning approach is simple, it does not guarantee a selection of optical split ratio which can optimally allocate bandwidth to end‐subscribers. In this paper, we develop an integrated mathematical framework for optimally dimensioning resources in an GPON access network, namely OLT capacity. This framework comprises three resource‐dimensioning approaches which are based on user requirements: GPON link utilization and capacity optimization. Our mathematical framework has been integrated into software for GPON resource dimensioning, which we have developed to evaluate the support and performance of services in GPON access networks. Copyright © 2011 John Wiley & Sons, Ltd.