基于SNMP的流量工程信息采集系统研究

首先提出了基于SNMP(简单网络管理协议)的流量工程网络管理框架模型，然后针对该模型中的网络信息采集部分进行开发和设计，实现了对网络资源和流量信息的实时采集，并对采集到的信息分析和统计，实现流量工程数据库的建立和维护，为流量工程的实施提供准确的流量测量数据和有效的网络管理依据。     

感知区分服务的MPLS流量工程技术研究

区分服务(Diffsevr)通过服务分级定义了流量的逐跳行为(PHB);流量工程(Traffic Engnineering)实现转发路径的优化。感知区分服务的MPLS流量工程(Diffsevr-aware MPLS Traffic Engnineering,简称DS-TE)将MPLS的区分服务与流量工程结合在一起,使其能够感知彼此的存在。DS-TE提出了基于类的资源分配思想,可以根据业务的类型,细粒度地建立交换路径,进一步保证了QoS。     

Diffserv-aware流量工程在MPLS中的应用

在多协议标签交换(MPLS)网络中,区分服务(Diffserv)对流量进行分类,为各种流量指定逐跳行为(PHB);流量工程(Traffic Engineering)实现转发路径的优化。感知区分服务的MPLS流量工程(DS-TE)将两者结合在一起,使其能够感知彼此的存在。DS-TE提出了基于类的资源分配思想,可以根据业务的类型,细粒度地建立交换路径,进一步保证了服务质量( QoS)。     

基于INT感知的5G核心网用户面流量调度系统

为解决5G移动数据流量激增和新型网络应用不断涌现给网络运维造成巨大压力的问题,设计并实现一个面向5G核心网用户面的流量调度系统,包含网络状态信息感知子系统和路由决策子系统。在网络状态信息感知子系统中,传统带内网络遥测方法带宽开销高,而且不是专门为无线网络系统设计的,此外,在5G核心网中应用带内网络遥测还面临测量精度不高、QoS无法保障等挑战。为此,提出了基于带内网络遥测的5G核心网用户面状态信息感知方案,将遥测信息插入GTP-U报文的扩展头部,实时检测UPF状态信息,实现网络状态动态随路测量。路由决策子系统实现了基于改进蚁群算法的流量调度算法,利用感知到的网络状态信息升级信息素函数更新方式,完成基于实时网络状态的路由决策。实际部署测试结果表明,网络状态信息感知子系统能正常感知网络信息,而且所做路由决策在时延、吞吐量和丢包率方面优于传统路由算法。     

MRTG、RRDTOOL在流量统计分析中的应用

在流量统计分析中MRTG应用甚广，但它不能长期保存流量信息。本文叙述了MRTG实现原理及基于MRTG、RRDTOOL实现流量数据保存到RRD数据库以实现流量信息的长期保存，并编程实现了历史流量的统计分析。     

基于二叉树的故障诊断信息录入技术

提出了一种基于二叉树的故障诊断信息录入技术。建立了故障树与二叉树的转换原则,并且在此基础上按照顶结点—子结点—兄弟结点的顺序,将故障信息依次按照规则录入数据库,以便实现故障信息的更新。通过实例验证了该项技术的可行性和高效率。该技术解决了以往在基于故障树的故障诊断过程中故障信息录入数据库时出现的效率低和繁琐的问题。     

超材料压缩感知成像技术

基于超材料和压缩感知理论设计了一套简便的快速成像系统,可用于毫米波及太赫兹(THz)成像,具有结构简单,成像速度快,在不同频段移植性强等优点。系统采用超材料结构互补(CELC)单元设计单通道成像口径,实现了对信息的物理层压缩。基于口径在不同频率辐射特性的不相关性,构造测量矩阵,以扫频方式实现对目标场景的稀疏测量,最后采用两步迭代阈值(TwIST)算法实现对目标场景的重构。已完成K波段、THz波段成像口径设计,以及K波段成像仿真实验,40 cm成像口径理论上具备4.6 cm的距离分辨力和1.3°的角度分辨力。     

一种P2P网络中基于位置感知的节点选择策略

P2P网络作为一种覆盖网络,邻居节点的选择若不考虑网络层、物理层信息,将导致较低的数据传输速度和不必要的跨运营商流量,从而大大限制P2P技术的应用。位置感知策略可以解决这些问题。本文对现有位置感知策略进行分类,并通过分析比较指出了现有位置感知策略的优缺点。提出了一种基于IP地址库的简单有效的节点选择策略,能够感知节点的运营商信息和物理位置。     

基于MySQL的云数据库分析与设计初探

云计算是在互联网的基础上建立的一种计算方式.通过该方式,软硬件的共享资源和信息都会在对应的设备或是计算机中被提供.而云计算中最主要的商业模式是PaaS.其中DaaS是PaaS平台中的基础功能,它可以利用MySQL数据库技术,进行系统架构和部署设计,以此来实现云数据库的服务.     

WDM网感知物理层光信道传输质量的量化标识

为支持QoS业务,WDM网络需感知物理层光信道的传输质量.由于光信号损伤具有随机波动性,感知信号损伤参数如果一有波动变化就发送信令,将浪费带宽资源.通过分析物理层光信号线性损伤的主要影响因素,建立可监测和可表述的感知参数,找出影响传输质量质变的临界值,并对其进行量化标识,以降低信令发送频率,从而节省带宽资源.     

一种实用的多数据库量子信息检索协议

针对目前量子私有信息检索不能适用与云存储的多数据库问题,基于现在成熟的量子密钥分发方法,提出了一种适合在多数据库环境下,实用的量子私有信息检索协议。对于不同大小的数据库,协议可通过调节参数θ和k,在保证数据库安全及用户隐私的情况下,完成信息的检索。性能分析结果表明,协议的通信复杂度低,检索成功率高、易于实施。     

A novel method of link-state update in wavelength-routed networks

Link-state update is a critical component of the routing protocol in wavelength-routed networks. High-frequency updates impose heavy traffic on network control channels as well as excessive burden of electronic processing, while stale link-state information seriously degrades network performance. Therefore, a tradeoff has to be made between control overhead and network blocking probability. This paper proposes a novel link-state update method. By actively regulating the link-state update rate, the proposed method efficiently handles the inherent burstiness of link-state changes without overloading control network with excessive update messages. To improve the blocking performance under limited control bandwidth, it assigns different types of updates with different priorities such that the stale link-state information of more negative impact has a higher chance to be removed. Comprehensive performance evaluations show that the method successfully enforces the control bandwidth quota while achieving much lower blocking probability than existing link-state update methods.     

EA-HD: a novel link state update mechanism for ASON

When a connection request comes in a mesh optical network, the routers automatically choose the suitable routing paths and wavelength to it according to the network topology and link-state information saved in its global link-state database. Because some of these wavelengths may be released or occupied at any time, the global state database is always out of date and need update by some update policy. A suitable link-state update policy is critical, since a high-frequency update policy imposes heavy burden on the network, while a low-frequency update would increase the inaccurate of the global link-state database. In this paper, we propose a link-state update policy, named the EA-HD policy, which considers two index of a link, one is the Hamming distance between the local link-state database and the global link-state database, and the other is the used ratio of its wavelengths. The proposed update policy gets a trade-off between the accurate of link-state information and its update cost. Simulation results prove that our scheme achieves a good performance in traffic blocking probability while maintaining moderate volume of update traffic.     

PNNI routing congestion control

There is evidence based on previous failures that link state protocols such as PNNI may not be able to recover from a widespread loss of topology database information or an overload of topology state updates. To prevent this, PNNI extensions have been adopted in the ATM forum to avoid going into congestion and to recover when congestion occurs. This article presents the adopted mechanisms to enable the PNNI routing protocol to avoid congestion states wherever possible, to respond gracefully to network overloads and failures, and to recover from massive loss of topology database information. The mechanisms include detecting congestion and notifying peers, reducing the rate of topology update control messages, maintaining link adjacencies with prioritized treatment of critical control messages, database backup, graceful recovery of lost topology database information, and database resynchronization. Simulation analysis demonstrates the effectiveness of these routing congestion control mechanisms.     

More efficient location tracking in PCS systems using a noveldistributed database system

In personal communication services (PCS), the complete location information and subscribers' profiles are kept in a database called the home location register (HLR). Another database, the visitor location register (VLR), is used to store partial location information. When a mobile user is called, the system queries the HLR to determine the location of the called party. Distributed databases have been introduced to improve the efficiency of querying the HLR. This paper presents an alternative means of constructing a distributed database. The proposed database design employs fixed pointers to link distributed data. Each database contains a portion of the system's information as well as several pointers. The pointers identify the location of real data, enabling the system to obtain the required information efficiently. The database of the proposed design is markedly smaller than the fully distributed databases since each database of the proposed design stores only partial information. Subscriber information is stored only in one database, thus allowing a single database, rather than multiple databases, to be updated. The single update presented herein notably reduces the signal traffic load. If the caller is in the registration area of some HLR, which holds the called party's information, the response time is significantly decreased since the transactions are served only by the local database. This phenomenon is referred to as the calling locality. The proposed method effectively shares the database and the network loading that originates from several databases' tracking mobile users in a PCS system. According to the results presented, this method is highly effective for systems with a heavy load and high calling locality. The single update feature of the proposed design reduces the traffic in the signaling link and the processing load of a database. However, the proposed method includes no fault tolerance and therein differs from the fully distributed design     

RFID安全认证协议研究

无线射频识别(RFID)技术的广泛应用给人们的生活带来了极大方便,但RFID系统中的安全隐患也应得到重视。分析了几种常用的RFID安全认证协议,针对密钥矩阵安全认证协议中密值更新出现不同步的问题提出了一种自同步的安全认证协议。当标签和数据库之间的密值更新出现不同步时,该协议能够自动使标签和数据库重新同步,有效解决标签和数据库之间密值更新不同步的问题。     

无线网络中的信息传输方式和安全保护

在介绍无线网络的同时,试图从网络各分层协议的角度,系统地归纳和比较了一些常见的适用于无线网络数据传输的优化技术。还针对各层协议,描述了无线网络中现有的安全机制,提出了一个比较全面的信息安全保护解决方案。采用RADIUS和ESSID认证、MAC地址过滤、WEP加密等机制来保护用户数据的私密性。     

Update-Based Cache Access and Replacement in Wireless Data Access

Cache has been applied for wireless data access with different replacement policies in wireless networks. Most of the current cache replacement schemes are access-based replacement policies since they are based on object access frequency/recency information. Access-based replacement policies either ignore or do not focus on update information. However, update information is extremely important since it can make access information almost useless. In this paper, we consider two fundamental and strongly consistent access algorithms: poll-per-read (PER) and call-back (CB). We propose a server-based PER (SB-PER) cache access mechanism in which the server makes replacement decisions and a client-based CB cache access mechanism in which clients make replacement decisions. Both mechanisms have been designed to be suitable for using both update frequency and access frequency. We further propose two update-based replacement policies, least access-to-update ratio (LA2U) and least access-to-update difference (LAUD). We provide a thorough performance analysis via extensive simulations for evaluating these algorithms in terms of access rate, update rate, cache size, database size, object size, etc. Our study shows that although effective hit ratio is a better metric than cache hit ratio, it is a worse metric than transmission cost, and a higher effective hit ratio does not always mean a lower cost. In addition, the proposed SB-PER mechanism is better than the original PER algorithm in terms of effective hit ratio and cost, and the update-based policies outperform access-based policies in most cases     

基于非对称QKD的股票交易数据库隐私查询协议

证券交易所的股票交易数据库中包含大量敏感信息,用户查询该数据库时保障账户及数据库的隐私十分重要.分析了非对称量子密钥分配(QKD)及其优良特性,提出了一种基于非对称QKD的不经意集合元素映射判定协议.该协议在查询数据库时保证了用户和数据库的隐私.安全性分析结果表明,该协议能有效抵抗量子存储攻击、伪造量子态攻击和纠缠测量攻击,具有很高的信道损耗容忍度.