网络通讯软件的发展趋势简析

网络通讯软件的发展趋势简析
    随着信息科学技术的迅速发展，人类每时每刻都会面对层出不穷的新技术、新概念。计算机技术、电子业、网络通信以及传输技术的快速发展，使得即时通信在各方面都有了长足的发展，其中以C/S结构为代表。
    客户端-服务器（C/S）技术最初是由基于主机的技术演化而来的。基于主机的技术是单处理器系统的自然而然的产物，可以追溯到计算的起源。在主机技术中，系统中的数据的处理和管理都是集中完成的。主机被很多外围客户终端围绕着，而这些终端仅仅简单地支持信息的表现。在客户端-服务器技术时代，客户端计算机成为了重要的处理资源。在个人计算机革命中客户端系统的处理速度不断上升，现在其处理速度可以与以前的小型机和大型机竞争了，甚至于超越了它们。最初为了支持部门和企业的数据访问，客户端-服务器技术支持了通过局域网连接到后端大型机、小型机和工作站服务器系统。在软件层中支持这种通讯的技术称为中间件（middleware）。最初，中间件是作为支持PC和服务器平台之间的客户端-服务器网络通讯的常规能力安装。随着技术的发展，中间件被逐渐嵌入操作系统中，这样它就变成了客户端平台和服务器平台的一种普通的能力。嵌有中间件的客户端系统现在支持对本地和通过网络运行的应用程序的服务。客户端-服务器技术向嵌入能力的演化给应用系统的执行增加了少量的挑战。       最近客户端-服务器技术正在逐渐被N层面向对象解决方案所代替。基于 JAVA应用程序服务器，N层解决方案包含了对瘦客户端用户界面的支持，同时增强了可伸缩性和可靠性。(所有权: 爱毕业设计网 www.2bysj.cn QQ:306826066)
现有的互联网主要是基于IPv4协议的。这一协议的成功促成了互联网的迅速发展。但是，随着互联网用户数量不断增长以及对互联网应用的要求不断提高，IPv4的不足逐渐凸现出来。其中最尖锐的问题就是不断增长的对互联网资源的巨大需求与IPv4地址空间不足的先兆，目前可用的IPv4地址已经分配了70%左右，其中，B类地址已经耗尽。据IETF预测，基于IPV4的地址资源将会在2005年~2010年枯竭；另外，由于IPv4地址方案不能很好地支持地址汇聚，现有的互联网正面临路由表不断膨胀的压力；同时，对服务质量、移动性和安全性等方面的需求都迫切要求开发新一代IP协议。(所有权: 爱毕业设计网 www.2bysj.cn QQ:306826066)

Development trend brief analysis of the network
communication software
    Along with the development of the information science technology rapidly, the humanity will face the new technologies, new concepts one after another incessantly at any time. The development of the computer technology, the electronics industry, the network communication and the transmission technology apace, made the timely communication great progress at some fields, and the C/S structure as the representative.
    The Client - Server (C/S) technology evolves from the host computer technology which the single processor system generates naturally, which may trace to the computer origin. In the host computer technology, data in system processing and the management is all completed in the central. The host computer is revolving by the some periphery customer terminals which merely simply support information performance. In the period of the Client - Server technology, the client computer becomes the important processing resources. The client system processing speed rises unceasingly during the personal computer revolution. Now its processing speed might compare beauty with the small machine and the large-scale machinery before, even had surpassed them. At first in order to support the department and enterprise's data accessing, the Client - Server technical has supported to connect through the local area network (LAN) to the rear end large-scale machinery, the small machine and the workstation server system. The technology which Supports this kind of communication in the software level is called as the middleware. At first, the middleware is installed to support the Client - Server network communication conventional ability between the PC and the server platform. Along with the technical development, the middleware is embedded in the operating system gradually, so it became one kind of ordinary ability in the client platform and the server platform. The client system which the middleware has been embedded in supports to the application procedure service which are operated through the local and the network now. The evolvement from the Client - Server technology to the embedded ability increases a few challenges for the application system execution.