网络体系结构与网络协议讲述.ppt

* * * * * 小结 网络体系结构与网络协议是网络技术中两个最基本的概念； 网络中计算机之间要做到有条不紊地交换数据就必须遵守一些事先约定好的规则。这些为网络数据交换而制定的规则、约定与标准被称为网络协议。功能完备的网络需要制定一系列的协议； 网络协议就是按照层次结构模型来组织的，网络层次结构模型与各层协议的集合定义为计算机网络体系结构； * 习 题 1.什么是分层网络体系结构？分层的含义是什么？ 2.画出OSI参考模型的层次结构，并简述各层功能。 3.简述TCP/IP四层结构及各层的功能。 4.比较OSI参考模型与TCP/IP参考模型异同。 * * Layer 1 of 2: Purpose: This figure orients the students to the OSI model. Emphasize: This model should be a review for students who attend this course. Gage the depth of your discussion around the knowledge of the students. Transition: The following layer discusses the lower layers of the OSI reference model. * Layer 2 of 2: Purpose: This figure orients the students to the next set of concepts. Emphasize: The Data Link layer of the OSI reference model is implemented by Switches and Bridges. These devices encapsulate date in “frames”. The Network layer of the OSI reference model is implemented by Routers. These devices encapsulate data in ‘packets’. The Transport layer of the OSI reference model is implemented by various protocols; one of which is TCP. TCP uses ports and encapsulates the data in ‘segments’. * Slide 1 of 4: Purpose: This figure orients the students to the application layer. Emphasize: This layer discusses network applications rather than computer applications. So, applications such as spreadsheets, word processors, or presentation graphics are not the applications being described here. Network applications may be applications that support, electronic mail, file transfer, remote access, network management, and so on. Transition: The following discusses the presentation layer. * Slide 2 of 4: Purpose: This figure orients the students to the presentation layer. Emphasize: This layer discusses code formatting, data presentation standards, and conversion. Transition: The following discusses the session layer. * Slide 3 of 4: Purpose: This figure orients the students to the session layer. Emphasize: This layer coordinates applications as they interact on different hosts