基于互联网通信基础的研究

Ipv6作为现有的Ipv4的更新版本,有效地解决了现存的位数过低、分配不合理、功能单一等诸多弊端,为网络的进一步发展提供了可靠的技术支持,然而无论从实际应用的角度还是单纯地讨论技术能力,仍有很多的问题需要我们去讨论研究,该文主要介绍Ipv6的先进性能与兼容性问题,其中涉及到DHCP的转变,IPSec在实际应用中的相关问题等。     

基于JMF的远程教育系统中实时音频的实现

现代远程教育系统中,音频传输是重要组成部分之一。为了实现现代远程教育中实时音频的传输,介绍了流媒体的相关技术及Java媒体框架的基本结构,描述了流媒体传输的两个基本协议RTP/RTCP,分析了基于JMF的流媒体数据传输的基本原理。阐述了远程教育系统中实时音频的采集与传输,并实现了怎样通过网络发送和接收远程教育系统中实时流媒体数据。音频、视频为远程教育提供了丰富多彩的教学手段,促进了我国教育事业的发展。     

双层二维网格结构间的Wormhole路由算法

二维网格结构由于其较好的可扩 展性而被越来越广泛地应用,因此对于二维网格结构多处理机间的数据通信,寻找一个好的路由算法也越来越重要。以Intel公司的Option Red机器为背景,分析了双层二维网格结构多处理机间的通信机制,并且针对该实际结构,根据单层二维网格结构中以Wormhole原理为基础的Unicast自适应路由算法,提出了适用于双层二维网格结构的无死锁的Wormhole路由算法。根据该算法得出的数据传输路径是无死锁的最短传输路径。     

单播丢包率的时域特征参数估计

网络链路丢包的时域特征参数（如：平均丢包长度、平均传输长度等）能够表现出链路丢包的突发性。现有的针对多播网络链路丢包时域特征参数的估计方法不能直接应用于单播网络。针对这一问题,提出用探测包群在单播网络中模拟多播端到端的测量过程,然后根据测量得到的数据对链路的连续传输概率（连续传输两个包的概率）和平均丢包长度等进行了估计。采用NS2进行仿真,验证了方法的性能。     

一类基于网络服务品质要求的单播路由算法

本文提出了一类基于网络服务品质QoS（quality of service）要求的单播路由算法。首先,我们给出了基于网络分组调度机制WFQ的延迟和带宽相耦合的分析模型,从而推导出了最佳端到端通信延迟的上界。基于该模型,我们改造了传统最小跳数和最短延迟的两类路由算法以支持实时通信的服务品质要求。此外,我们还给出了两种新的服务品质路由算法,它们是多路径第k条最短延迟路由算法以及组合带宽和跳数（hop counts）的最大能量路由算法。仿真实验结果表明,四种算法尤其是后两种算法在满足用户带宽、延迟服务要求以及增加网络资源使用效率和网络吞吐率等方面各有特色。     

W5300在嵌入式以太网通信中的应用

随着通信技术的发展,通信系统网络化已成为主流发展趋势。通过将W5300应用于嵌入式终端,实现了计算机与终端在UDP协议下以太网通信。介绍了系统总体方案和软硬件设计,对W5300工作流程进行了描述,给出了W5300在系统中的典型配置。通过试验测试,实现了W5300在UDP局域网中的单播和组播通信。     

Interference coordination schemes for cellular network assisted device-to-device multicast

In this paper, a multicast concept for device-to-device （D2D） communication underlaying a cellular infrastruc~tre is investigated. To increase the overall capacity and improve resource utilization, a novel interference coordination scheme is proposed. The proposed scheme includes two steps. First, in order to mitigate the interference from D2D multicast transmission to cellular networks （CNs）, a dynamic power control scheme is proposed that can determine the upper bound of D2D transmitter power based on the location of base station （BS） and areas of adjacent cells from the coverage area of D2D multicast group. Next, an interference limited area control scheme that reduces the interference from CNs to each D2D multicast receiver is proposed. The proposed scheme does not allow the coexistence of cellular user equipments （CUEs） located in the interference limited area to reuse the same resources as the D2D multicast group. From the simulation results, it is confirmed that the proposed schemes improve the performance of the hybrid system compared to the conventional ways.     

流媒体广播及点播系统的设计与应用

分析视频课件制作和视频流传送的基本过程，提出基于MPEG-4的流媒体视频课件广播／点播系统的设计和实现方法，为当前开展远程网络实时教学和视频点播提供新的思路。     

Unicast probing techniques for estimation of shared loss rate

The paper introduces two new unicast active end‐to‐end measurement techniques, called the single–double unicast probing (SDUP) and the delay‐based unicast probing (DUP), to estimate the rate of losses which occurs on the shared network path of two flows. A comprehensive performance evaluation and a comparison between these two techniques and an existing one having the same objective, the striped unicast probing (SUP) (Proceedings of the INFOCOM 2001—The IEEE Conference on Computer Communications, No. 2, Anchorage, Alaska, U.S.A., 2001; 915–923), were carried out. We demonstrate that our proposed SDUP technique provides even better estimation accuracy compared to that of the SUP while it requires only one piece of measurement equipment at only one receiver instead of deploying units to both receivers. Furthermore, with only one sender and receiver pair we can measure not only one shared path, but any partial path that begins at the sender and is located on the sender–receiver path. We also show that while the DUP have the same accuracy as the SUP in the case of Drop‐Tail buffer management, the DUP is capable of measuring loss rates of RED buffers, which the other techniques do not work with. The SDUP and the DUP are less intrusive and cause less bursty traffic compared to the SUP. Finally, the adaptation of these techniques into passive measurements is also considered. Copyright © 2006 John Wiley & Sons, Ltd.     

关于IPTV技术的探讨

介绍由电视广播网、互联网和电话网连接起来的IPTV系统，叙述IPTV的系统结构和相关的技术要求。