第一层,在OSI模型中的物理层是控制数字数据位(bits)从发送设备(源)的物理层通过网络通讯媒介到达接收(目的)设备物理层。物理层的技术包括:以太网电缆( Ethernet cables)和令牌环网络(Token Ring networks)。除此之外,集线器(hub)和其他中继器(repeaters)以及电缆连接器也是工作在网络层的标准网络设备。 在物理层,使...
The 7 layers of the OSI model The OSI model divides networking up into a “vertical stack” consisting 7 layers. Networking starts on the application layer at the top (Layer 7) and proceeds to the bottom layer (Layer 1). It is then passed back up the same hierarchy. ...
OSI uses three layers -- application, presentation and session -- to define the functionality of upper layers, while TCP/IP uses only the application layer. OSI uses two separate layers -- physical and data-link -- to define the functionality of the bottom layers, while TCP/IP uses only t...
MELENDEZ W A ET AL: " THE UPPER LAYERS OF THE ISO/OSI REFERENCE MODEL (PART II) " COMPUTER STANDARDS AND INTERFACES, ELSEVIER SEQUOIA. LAUSANNE, CH, vol. 5, no. 2, 1986, pages 65-77, XP000814414 ISSN: 0920-5489Melendez, W. A., Petersen, E. L., "The Upper Layers of the ISO...
The 7 layers of the OSI model Cross-layer functions Cross-layer functions, or services that may affect more than one layer, include the following: security service telecommunication as defined by the International Telecommunication Union Standardization Sector (ITU-T) X.800 recommendation; ...
To ensure reliable delivery, the transport layer builds on the error-control mechanisms provided by lower layers. If lower layers are not adequate, the transport layer is the last chance for error recovery. The session layer provides the control structure for communications between applications. It ...
Objectives What is the purpose of a Network model? What are the layers of the OSI model? What are the characteristics of each layer of the OSI model? How does the TCP/IP stack compare to the OSI model? What are the well-known TCP and/or UDP port numbers for a given collection of ...
Each of the layers of the OSI model is intended to function with those above and below it respectfully within the model definition. The OSI model defines standards for: The way in which devices communicate between each other. The means used to inform devices when to send data and when not ...
Breaking down the OSI Model Looking at the OSI Model, notice that the seven layers are further grouped into three higher layers. These groupings allow us to generally refer to OSI model function — software, Heart of OSI, hardware — without getting into the specific functions of each layer....
OSI模型的数据链路层(Data Link Layer)(即第2层)负责为数据包添加头和尾,为数据包可以转换为适合于局域网和广域网线路传输的二进制格式做准备。第2层可以分为两个功能子层,上子层是逻辑链路控制(Logical Link Control,LLC)子层,并在IEEE 802.2规范中定义,它与数据链路层之上的网络层(NetworkLayer)通信。LLC...