Analysis of TCP/IP protocol

The TCP/IP protocol is not a collectively known protocol for TCP and IPs, but rather refers to the entire TCP/IP protocol family. TCP/IP Protocol module relationship from the aspect of protocol layered model, TCP/IP consists of four levels: network interface layer, network layer, Transport layer and application layer. The  TCP/IP protocol does not fully conform to the OSI seven-layer reference model, and the OSI (Open System interconnect) is a traditional open systems interconnect Reference Model and is a 7-layer abstract Reference Model of the communication protocol, where each layer performs a specific task. The purpose of this model is to enable various hardware to communicate with each other at the same level. These 7 layers are: Physical layer, Data Link layer (network interface layer), Network layer (network layer), Transport layer (transport layer), Session layer, presentation layer, and Application layer (application layer). The TCP/IP protocol uses a 4-tier hierarchy, each of which calls the network provided by its next layer to fulfill its own needs. Because ARPANET designers focus on the interconnection of the network, allowing the communication subnet (network interface layer) to adopt existing or future protocols, so this level does not provide a special protocol. In fact, the TCP/IP protocol can be connected to any network through the network interface layer, such as X. Switch network or IEEE802 LAN. The  TCP/IP Reference model is the network architecture that is used first by ARPANET. This architecture is referred to as the TCP/IP Reference Model (TCP/IP Reference models) after its two major protocols appear. This network protocol is divided into four layers: network access layer, Internet layer, Transport layer and application layer. The   network access layer, which is not described in detail in the TCP/IP reference model, simply indicates that the host must be connected to the network using some kind of protocol. The   Internet layer is a key part of the entire architecture, and its function is to enable the host to send packets to any network, and to make the packets go independently to the target. These groupings may pass through different networks, and the order of arrival and the order in which they are sent may vary. High-level if you need to send and receive sequentially, you must handle the sorting of the groupings yourself. Internet layer uses Internet Protocol (Ip,internet Protocol). The network layer of the TCP/IP Reference Model's Internet layer and the OSI Reference Model are functionally similar. The   Transport layer (Tramsport layer) allows the peer entities on the source and destination machines to have sessions. At this level, two end-to-end protocols are defined: Transmission Control Protocol (Tcp,transmission-Protocol) and User Datagram Protocol (udp,user Datagram Protocol). TCP is forConnected protocols, which provide reliable message transmission and connection services to upper-level applications. For this reason, in addition to basic data transmission, it also has the functions of reliability assurance, flow control, multiplexing, priority and security control. UDP is a non-connected, unreliable transport protocol that is used primarily for applications that do not require the ability to sort and flow control of TCP. The application layer (application layer) contains all the high-level protocols, including: Virtual Terminal Protocol (telnet,telecommunications NETwork), File Transfer Protocol (Ftp,file Transfer Protocol), e-Mail Transfer Protocol (smtp,simple Mail Transfer Protocol), Domain Name Services (dns,domain name Service), online News Transfer Protocol (Nntp,net News Transfer Protocol) and Hypertext Transfer Protocol (Http,hypertext Transfer Protocol). Telnet allows a user on a machine to log on to a remote machine and work; FTP provides a way to effectively move files from one machine to another; SMTP is used to send and receive e-mail messages; DNS is used to map host names to network addresses; NNTP for news publishing, retrieval, and acquisition HTTP is used to get the home page on www.

Analysis of TCP/IP protocol