Communication Protocol knowledge (Memo)

TCP/IP (short for Transmission Control Protocol/Internet Protocol) is the most basic Internet protocol, is composed of the underlying IP protocol and TCP protocol. TCP/IP protocol is a set of protocols, including TCP (Transmission Control Protocol) and IP (Internet Protocol), UDP (User datasync protocol), and ICMP (Internet Control Message Protocol) protocol and other protocol groups. The traditional Layer 7 includes the physical layer, data link layer, network layer, transmission layer, voice, presentation layer, and application layer. The TCP/IP communication protocol uses a layer-4 hierarchy. Each layer calls the network provided by its next layer to meet its own needs:
A) Application Layer: Application ProgramInter-communication layer, such as simple Email transmission (SMTP), file transfer protocol (FTP), and network remote access protocol (Telnet.
B) Transport Layer: In this layer, it provides data transmission services between nodes, such as transmission control protocol (TCP) and User Datagram Protocol (UDP, TCP and UDP add transmitted data to the data packet and transmit it to the next layer. This layer is responsible for transmitting data and confirming that the data has been delivered and received.
C) Interconnection Network Layer: provides basic data packet transmission functions so that each data packet can reach the target host (but does not check whether it is correctly received), such as Internet Protocol (IP ).
D) network interface layer: manages the actual network media and defines how to transmit data using the actual network (such as Ethernet and serial line.
HTTP: Hypertext Transfer Protocol (HTTP) is an application layer protocol. It is applicable to distributed and cooperative hypermedia information systems due to its simple and fast method. HTTP allows the use of a free reply method to indicate the purpose of the request. It is based on the reference principle provided by the Uniform Resource Identifier (URI) and serves as an address (URL) or name (URN ), it indicates the method used to transmit messages in a format similar to the network mail and multi-purpose Internet Mail extended protocol (MIME. HTTP is a request/response protocol.