What is agreement
From an application point of view, the protocol can be understood as a " rule ", which is the rule for data transmission and data interpretation.
Assume that both parties A and B want to transfer files. Provisions: the
first time, the file name is transmitted, the receiver receives the file name, and responds OK to the transmitter; the
second time, the size of the file is sent, and the receiver receives the data and responds with an OK; the
third time, the file content . Similarly, the receiver responds OK after receiving the data, indicating that the file content is successfully received.
Therefore, no matter what kind of file is transferred between A and B, it is completed through three data transfers. A simplest data transmission rule is formed between A and B. Both parties send and receive data according to this rule. The mutual compliance rule reached between A and B is an agreement.
This kind of agreement that is only observed between A and B is called the original agreement . When this agreement is adopted by more people, it will continue to increase, improve, maintain, and improve. Finally, a stable and complete file transfer protocol is formed, which is widely used in various file transfer processes. This agreement becomes a standard agreement . The earliest ftp protocol was derived from this.
The TCP protocol focuses on data transmission. The http protocol focuses on the interpretation of data.
Typical protocols The
common protocols of the transport layer are TCP/UDP .
Common protocols at the application layer include HTTP and FTP .
Common protocols at the network layer include IP, ICMP, and IGMP.
Common protocols at the network interface layer include ARP ,RARP protocol.
TCP Transmission Control Protocol (Transmission Control Protocol) is a connection-oriented, reliable, byte stream-based transport layer communication protocol.
UDP User Datagram Protocol (User Datagram Protocol) is a connectionless transport layer protocol in the OSI reference model, which provides transaction-oriented simple and unreliable information transmission services.
HTTP Hyper Text Transfer Protocol (Hyper Text Transfer Protocol) is the most widely used network protocol on the Internet.
FTP File Transfer Protocol (File Transfer Protocol)
IP protocol is the Internet Protocol (Internet Protocol)
ICMP protocol is the Internet Control Message Protocol (Internet Control Message Protocol), it is a sub-protocol of the TCP/IP protocol suite, used in the IP host , Transfer control messages between routers.
The IGMP protocol is the Internet Group Management Protocol (Internet Group Management Protocol), which is a multicast protocol in the Internet protocol family. The protocol runs between the host and the multicast router.
The ARP protocol is a forward address resolution protocol (Address Resolution Protocol), which finds the MAC address of the corresponding host through a known IP.
RARP is a reverse address translation protocol, which determines the IP address through the MAC address.