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...
The Open Systems Interconnection (OSI) model is a conceptual model that divides network communication and interoperability into seven abstract layers.
The application layer is the seventh layer in the OSI model. Though the name might be deceiving, it’s not an actual application; rather, it’s a component within an application that manipulates information. It’s essentially designed to provide network services to the end user. Users can tra...
Each layer of the OSI model interacts with the layer directly above and below it, encapsulating and transmitting data in a structured manner. This approach helps network professionals troubleshoot issues, as problems can be isolated to a specific layer. The OSI model serves as a universal language...
In the context of networking, a switch is a device that connects devices together in a computer network, enabling them to communicate with each other by exchanging data packets. A switch operates at the data link layer of the OSI model. With a switch, it's possible for wired network device...
Layer 1: Physical Layer The Physical Layer serves as the foundation of the OSI Model, focusing on the actual transmission of data in its raw bit form over a physical medium. Its essential functions encompass: Encoding and Signaling: Encoding bits into electrical or optical signals suitable fo...
According toCloudflare, “A WAF or web application firewall helps protect web applications by filtering and monitoring HTTP traffic between a web application and the Internet.” Acting as a layer7defense in the OSI model, WAFs safeguard applications from varioustypes ofattacks, including cross-site...
How does a Switch Work? The question of what is network switching is directly related to its building blocks of switches which are used to connect multiple computers and other devices, while routers are used to connect networks. Switches operate at Layer 2 of the OSI model (the data link l...
Network layer Access switch A switch working at the access layer, which is inexpensive and has a high port density, suitable for directly connecting IT devices and networks. Aggregation switch A switch working at the aggregation layer as an aggregation point of multiple access switches, with a hi...
The session layer is Layer 5 of theOSIcommunications model. It is the long-lived logical connection that persists between endpoints over time. A single session is all the back-and-forth communication between two endpoints. It helps a protocol to be more consistent and reliable. The TCP/IP pro...