Basic network knowledge: Protocol group

To learn about networks, you must be familiar with the network layers and protocol groups. Among them, the most famous is the TCP/IP protocol group. We will introduce the overall structure in this regard systematically. This article emphasizes the concept and definition of network layers and protocol groups. To ensure that the communication system is complete and effective, a complete set of protocols must be constructed. To avoid duplication, each protocol only needs to have the communication function that does not process other protocols. How can we ensure that all protocols can be well coordinated? This requires an overall design plan-the design of each protocol should not be isolated, but should be integrated and coordinated to design all protocols, called protocol groups or Protocol clusters. Each protocol in the protocol group only processes part of the communication function, and all protocols are combined to complete all communication functions, including hardware failure and other unexpected situations. In addition, a complete protocol group should be able to work in an efficient and coordinated manner.

Integrate various protocols into a unified abstract structure, called the layered model layering model ). Essentially, the layered model describes how to divide all aspects of communication into a block structure for coordination. Each block is called a layer ). Because these protocols in the protocol group are organized into a linear sequence, the term "layer" is generated. The Protocol is divided into different layers so that they can focus on a part of the communication processing function at a given time, which helps reduce the complexity of protocol design and implementation.

In verbal terms, people refer to the visual image used to display the layered model as a stacked stack), and protocol groups or protocol clusters are also called protocol stack stacks ). This term refers to the protocol software in the computer. For example, "Does the computer run the TCP/IP protocol stack ?"

In the following chapters, we will explain the protocol in detail to help us understand the hierarchy. Here, we only need to understand the purpose of each layer and how to use protocol groups for communication. The subsequent sections briefly describe the roles played by each layer and how data passes through each layer during computer communication.

Layer 2: Physical Layer

The physical) Layer Protocol specifies the details of the underlying transmission media and related hardware. All regulations relating to electrical properties, radio frequencies, signals, and so on belong to layer 1st.

Layer 3: Network Interface Layer

Network interface (network interface) The Layer Protocol specifies the communication details between a higher protocol layer (usually implemented by software) and the underlying network (implemented by hardware. The specifications for network addresses, maximum group lengths supported by the network, protocols used to access the underlying media, and hardware addressing all belong to layer 2nd.

Layer 3: Network Interconnection layer

Internet) layer protocols form the most important foundation of the internet. The layer-3 Protocol specifies that two computers communicate over the Internet through multiple interconnected networks. The addressing structure of the Internet, the grouping format of the Internet, the methods for dividing large groups into small groups for transmission, and the error reporting mechanism all belong to layer 3rd.

Layer 3: Transport Layer

Transport Layer Protocol provides communication means between applications on one computer and applications on another computer. The specifications that control the maximum rate of data that can be received at the acceptor, prevent network congestion, and ensure that all data is received in the correct order belong to layer 4th.

Layer 3: Application Layer

The application layer is the top layer of the TCP/IP protocol group, which specifies how an application process interacts during their communication. This layer of agreement also specifies the meaning and format of the message exchanged by the application process, as well as the procedures to be followed in the communication process. The specifications for email exchange, file transmission, Web browsing, telephone services, and video conferencing all belong to layer 5th.