Multimedia streaming gateway with jitter detection

This paper investigates a novel active buffer management scheme, "Jitter Detection" (JD) for gateway-based congestion control to stream multimedia traffics in packet-switched networks. The quality of multimedia presentation can be greatly degraded due to network delay variation or jitter when transported over a packet-switched network. Jitter degrades the timing relationship among packets in a single media stream and between packets from different media streams and, hence, creates multimedia synchronization problems. Moreover, too much jitter will also degrade the performance of the streaming buffer in the client. Packets received by the client will be rendered useless if they have accumulated enough jitter. The proposed active buffer management scheme will improve the quality of service in multimedia networking by detecting and discarding packets that accumulated enough jitter, such as to maintain a high bandwidth for packets within the multimedia stream's jitter tolerance. Simulation results have shown that the proposed scheme can effectively lower the average received packet jitter and increase the goodput of the received packets when compared to random early detection (RED) and DropTail used in gateway-based congestion control. Furthermore, simulation results have also revealed that the proposed scheme can maintain the same TCP friendliness when compared to that of RED and DropTail used for multimedia streams.     

Analysis of mobile agents in network fault management

Network domains have become more and more advanced in terms of their size, complexity and the level of heterogeneity. Comprehensive fault management is the most significant challenge in network management. Fault management can help increase the availability of the network by quickly identifying the faults and then, proactively, start the recovery process. Current centralized configured network management systems suffer from problems such as insufficient scalability, availability and flexibility as networks become more distributed. Mobile agents (MAs), with integral intelligence, can present a reasonable new technology that will help to achieve distributed management, several researchers have embraced these approaches. In this paper, we introduce a general analytical model for network management client/server (CS) and MA paradigms. We express how to build up an analytical framework, which can be used to quantitatively assess the performances of the MA and CS paradigms under different scenarios. We present some numerical and experimental results that demonstrate the applicability of our proposed framework, which will be based on a combination of MA and CS schemes called Adaptive Intelligent Mobile Agent.     

Dynamic playout scheduling algorithms for continuous multimedia streams

In this paper, we investigate a playout scheduling framework for supporting the continuous and synchronized presentations of multimedia streams in a distributed multimedia presentation system. We assume a situation in which the server and network transmissions provide sufficient support for the delivery of media objects. In this context, major issues regarding the enforcement of the smooth presentation of multimedia streams at client sites must be addressed to deal with rate variance of stream presentations and delay variance of networks. We develop various playout-scheduling algorithms that are adaptable to quality-of-service parameters. The proposed algorithms permit the local adjustment of unsynchronized presentations by gradually accelerating or retarding presentation components, rather than abruptly skipping or pausing the presentation materials. A comprehensive experimental analysis of the proposed algorithms demonstrates that our algorithms can effectively avoid playout gaps (or hiccups) in the presentations. This scheduling framework can be readily used to support customized multimedia presentations.     

分布式网络协议分析系统的设计与实现

本文给出了一个分布式网络协议分析系统的设计与实现,记叙比试在于通用的网络管理框架设计,具有分布式的数据采集与集中式的数据分析的特点,可以实现多子网企业内部网的分布式协议分析功能。     

基于MIB构建网络管理领域本体方法研究

为了解决用统一语义模型描述网络管理信息的问题,通过研究网络管理模型和本体构建方法,提出一种由管理信息库MIB构建网络管理领域本体方法。该方法在半结构化管理信息库定义文本中采用映射和关联规则方法,构建本体的类、关系和公理。通过实验验证了该方法可行性。     

SNMP网络管理中管理信息库结构与功能

本文详细论述了ＳＮＭＰ网络管理中的管理信息库结构与功能。     

基于OSI的CIMS网络管理信息库的设计与实现

本文根据OSI的管理框架提出了一种面向CIMS网络管理的管理信息库(MIB)的实现结构,它包括使用包含树的概念来表示管理信息,利用OSI的CMIS来控制对MIB的访问,使用文件系统来存放管理信息。文章还介绍了MIB实现结构在Unix系统的实现。     

面向大型网络的多管理对象信息的组预取算法

如何减少网络管理系统对网络带宽的占用是网络管理研究的难点之一.结合管理信息库(management information base,简称MIB)信息的收集策略直接影响着网管系统性能的特点,针对异构大型网络环境下多管理对象的信息收集问题,提出了一种从多个被管设备中提取有关MIB信息的新算法--组预取算法(group-prefetching algorithm,简称GPA).该算法能在不改变现有的网络管理协议的情况下,将多个分散的、在未来一段时间内的MIB对象的访问组合在一个预取组中进行访问,减少对管理对象的访问频度,从而可以较少地消耗所用的网络带宽和CPU资源,减小整个网络开销.     

关于网络安全管理系统的若干思考

随着信息安全技术的发展，大量安全解决方法和产品涌现，但这也为网络信息系统的安全管理带来了很大的挑战。随着网络应用的普及，我们越来越需要一个统一的网络安全管理系统。本文说明了采用网络管理技术来实现安全管理的好处，并提出了一个基于SNMP和MIB的安全管理平台的模型。     

A generic content-based image retrieval framework for mobile devices

Multimedia mobile devices have created new possibilities for developing and accessing a variety of multimedia items such as images, audio and video clips. Personal multimedia items are, nowadays, being consumed at an enormous rate. Therefore, the management of these media items has become a pressing problem. In this paper, a client-server content-based image retrieval framework for mobile platforms is developed, which provides the capability of content-based query and browsing from mobile devices. The proposed framework provides an adaptive user interface and a generic structure, which supports a wide range of mobile devices. In this framework, a client requests the server for retrieval of particular images with a particular content. The server performs a content-based retrieval of images from a selected database and streams the retrieved results back to the client in an efficient way. The query results are transmitted over a wireless network and a certain number of similar images are rendered on the mobile device screen using thumbnail sizes. The proposed framework serves as a basis of content-based image retrieval on mobile devices. It addresses several important challenges such as hardware and software limitations as well as efficient use of the available network bandwidth.     

SNMP协议在网络管理中的应用

论文首先分析了SNMP协议的概念,以及其重要的组成部分MIB,然后设计开发了基于SNMP的网络管理软件。给出了主要的程序框架,应用SNMP进行网络管理可以为我们综合应用、管理网络带来很大的方便,本文有着较强的实际应用价值。     

基于SNMP网络管理协议的MIB库分析及存取实现

介绍了SNMP是用于网络管理/代理之间的请求/应答协议。管 理信息库(MIB)定义了由代理者维护的各种变量,它们由管理者来进行存取操作,从而实现 具体的网络管理。通过对MIB的分析,提出了某系统中对MIB的基本访问实现方法。     

Comparison criteria for GDMO-based network management information models: A step towards the integration of management systems

The integration of Management Information Bases (MIBs) is one of the challenges of integrated network management. This is made more difficult by the existence of many different ways for structuring the MIB and defining managed objects. This paper addresses the issue of integrating GDMO-based MIBs created on the basis of different Management Information Models (MIMs). Three MIMs (NMF Library Release 1. 1, ITU-T M. 3100 and ETSI GOM) are analyzed with the help of a simple network configuration, and some MIM comparison criteria are proposed. The criteria can be used to assess the dificulty of integrating MIBs based on those models.     

面向XML的SNMP MIB数据转换模式研究

MIB是SNMP网络管理的主体,传统的MIB编译方法缺乏管理扩展的灵活性和有效性。基于MIB描述规范SMI和XML Schema语法特征分析,研究SMI到XML Schema的MIB数据转换模式;综合XML数据交换和脚本语言编程,提出一种支持SMI到XML Schema映射的SNMP MIB数据转换器实现架构,并对其在网络管理中提供MIB数据转换的优势进行详细说明。     

Management of virtual network resources for multimedia applications

The Internet is the primary means for multimedia content sharing, playing a central role in the lifestyle of users. As a consequence, in the past few years, the traffic demand for access and edge networks has increased (video stream downloading, videoconferencing or even the broadcasting of video streams through the Internet), since multimedia applications have strict requirements, including high bandwidth, small amount of loss and low delay. To address this scenario, the edge as a service (EaaS) paradigm arises as a suitable approach to increasing the quality of Internet access. The EaaS uses network virtualization and software-defined networks to improve the resource utilization and manageability. Within this context, this article proposes a framework to manage the virtual network resource (VNR) according to the multimedia application characteristics, and not only the network requirements. Additionally, a study about the relationship between quality of experience (QoE) and VNR availability was performed to be used as a basis for a proposed resource allocation adjustment mechanism. Experiments using real multimedia traffic under distinct scenarios demonstrate the effectiveness of the proposed framework to ensure the QoE of users through the management of the VNR.     

XML技术在网络管理中的应用

在基于SNMP的网络管理中，MIB数据是使用ASN．1描述BER编码的，可读性不强。而XML因其良好的自描述性和结构化特征，非常适合表示MIB数据。讨论了用XML表示MIB数据的方法，使用此方法，实现了一个SNMP与XML之间的转换系统。     

Service Adaptability in Multimedia Wireless Networks

Next-generation wireless communication systems aim at supporting wireless multimedia services with different quality-of-service (QoS) and bandwidth requirements. Therefore, effective management of the limited radio resources is important to enhance the network performance. In this paper, we propose a QoS adaptive multimedia service framework for controlling the traffic in multimedia wireless networks (MWN) that enhances the current methods used in cellular environments. The proposed framework is designed to take advantage of the adaptive bandwidth allocation (ABA) algorithm with new calls in order to enhance the system utilization and blocking probability of new calls. The performance of our framework is compared to existing framework in the literature. Simulation results show that our QoS adaptive multimedia service framework outperforms the existing framework in terms of new call blocking probability, handoff call dropping probability, and bandwidth utilization.      

Buffer model and management in distributed multimedia presentation systems

The delivery of continuous and synchronous multimedia data from a database (or file) server to multiple destinations over a network presents new challenges in the area of buffer management. Many factors that were not considered in conventional buffer management must be examined. In this paper, we investigate the principles of buffer model and management for multimedia data presentations in distributed systems. The primary goal is to minimize the response time of multimedia presentations while ensuring that all continuity and synchronization requirements are satisfied. A framework for buffer model and management is introduced. Minimum buffering requirements at both client and server sides to guarantee the continuity and synchrony of the presentation of multimedia data are examined. A prefetching and replacement strategy which satisfies these requirements is then offered. These principles and techniques provide users with the full range of information required to develop a distributed system for multimedia presentations.     

CyVOD: a novel trinity multimedia social network scheme

How to comprehensively explore, improve and deploy multimedia social networks (MSNs) has become a hot topic in the era of emerging pervasive mobile multimedia. More and more MSNs offer a great number of convenient tools, services, and applications for multimedia contents including video and audio that users share willingly and on demand. However, concerns with digital rights management (DRM)-oriented multimedia security, as well as the efficiency of multimedia usage and sharing are meanwhile intensified due to easier distribution and reproduction of multimedia content in a wide range of social networks. The paper proposes a comprehensive framework for multimedia social network, and realized a cross-platform MSN prototype system, named as CyVOD, to support two kinds of DRM modes. The proposed framework effectively protects copyrighted multimedia contents against piracy, and supports a more efficient recommendation system for its better handling of the tradeoff between multimedia security and ease of use.     

Internet Network Resource Information Model

The foundation of any network management systems is a database that contains information about the network resources relevant to the management tasks.A network information model is an abstraction of network resources,including both managed resources and managing resources,In the SNMP-based management framework,management information is defined almost exclusively from a “Device“ viewpoint,namely managing a network is equivalent to managing a collection of individual nodes.Aiming at making use of recent advances in distributed computing and in object-oriented analysis and design,the Internet management architecture can also be based on the Open Distributed Processing Reference Model(RM-ODP).The purpose of this article is to provide an Internet Network Resource Information Model.First,a layered management information architecture will be discussed.Then the Internet Network resource information model is presented.The information model is specified using object-Z.