Questions about TCP/IP network protocol

Questions about TCP/IP network protocol

Question 1: What is network protocol?

The so-called network protocol means that two computers must abide by the common rules to communicate, just like two people must use the same language to communicate. A person who only understands English cannot communicate with a person who only understands Chinese because there is no common language (rule. The common rule for communication between two computers is the network protocol.

Question 2: Who makes the network protocol and why does the network need to be divided in layers?

The International Organization for Standardization (ISO) defines the basic framework of network protocols, known as the OSI model. There will be A lot of content to develop communication rules. For example, you need to consider how computer A finds computer B and whether computer A needs to provide feedback when sending information to computer B, what is the format of the data transmitted by computer A to computer B? The content is too much and too complex. Therefore, the OSI model divides these communication standards into layers, and each layer solves the problem of a category, which makes standard formulation less complex. The layer-7 standard models developed by the OSI model are: application layer, presentation layer, Session Layer, transmission layer, network layer, data link layer, and physical layer.

Question 3: What is the difference between the TCP/IP protocol and the OSI model?

Although the International Organization for Standardization has developed such a network protocol model, the network protocol used by Internet communication is TCP/IP.

TCP/IP is a protocol family, which is also divided by layers. Four layers: application layer, transmission layer, interconnection network layer, and network interface layer. What is the difference between the TCP/IP protocol and the OSI model? The OSI network protocol model is a reference model, and the TCP/IP protocol is a de facto standard. The TCP/IP Protocol references the OSI model, but it does not strictly follow the layer-7 criteria defined by OSI, but only divides layer-4. I think this will be simpler, when too many layers are divided, it is difficult to tell which level a protocol belongs. The TCP/IP protocol does not conflict with the OSI model. The application layer protocol in the TCP/IP protocol corresponds to the application layer, presentation layer, and Session Layer in the OSI. Just like the former Ministry of Industry and the Ministry of Information Industry, there is only one department after the implementation of the Ministry of Industry and Information Technology, but this department still has to do the same things as the previous two departments, essentially there is no big difference. There are two important protocols in TCP/IP, namely the TCP protocol at the transport layer and the IP protocol at the Interconnection layer. Therefore, the two Protocols are used as representatives to name the entire protocol family, the TCP/IP Protocol refers to the entire Protocol family.

Question 4: What is the difference and Connection Between TCP and UDP?

The main transport layer protocols are TCP and UDP. The difference between the two rules is that the TCP protocol requires feedback from the receiver, and the UDP protocol does not need feedback from the receiver. TCP is like A registered email. After computer A sends A message to computer B, you need to get feedback from computer B so that computer A can know whether computer B has received the message. UDP is like A normal mail. After computer A sends A message to computer B, computer B does not send A token to computer A. After computer A sends the message, it does not know whether computer B has received the message. Therefore, TCP transmission is more reliable than UDP transmission, but TCP transmission is less efficient than UDP. As for the specific transfer method selected during the transfer process, specific problems need to be analyzed. In the process of unreliable network transmission, select TCP transmission mode. You can use the UDP mode to increase the transmission rate if you are concerned about efficiency or do not care about transmission errors.