What is TCP/IP protocol
TCP/IP protocol (Transfer Controln Protocol/Internet Protocol) is called transmission control/internet protocol, also known as network communication protocol. This protocol is the basis of the Internet international network.
TCP/IP is the basic communication protocol used in the network. Although TCP/IP includes two protocols, Transmission Control Protocol (TCP) and Internet Protocol (IP), TCP/IP is actually a set of protocols, which includes hundreds of protocols with various functions, such as remote login, file transfer and email, etc. The TCP protocol and IP protocol are two basic and important protocols to ensure the complete transmission of data. It is usually said that TCP/IP is an Internet protocol family, not just TCP and IP.
Data transmission
The basic transmission unit of the TCP/IP protocol is datagram. The TCP protocol is responsible for dividing the data into several data packets and adding a packet header to each packet (like adding an envelope to a letter). The packet header has a corresponding number to ensure that the data can be restored to the original format at the data receiver. The IP protocol adds the host address of the receiver on each packet header, so that the data can find the place you want to go (just as if the address is written on the envelope). If data is lost, data distorted, etc. occur during the transmission process, the TCP protocol will automatically require data to be retransmitted and regroup the packet. In short, the IP protocol ensures the transmission of data, and the TCP protocol ensures the quality of data transmission.
The transmission of TCP/IP protocol data is based on the four-layer structure of the TCP/IP protocol: application layer, transmission layer, network layer, and interface layer. When data is transmitted, a packet header must be added to the data every time it passes through one layer. The data in it is for the same layer protocol at the receiving end. On the receiving end, the used packet header must be removed every time it passes through, so as to ensure that the format of the transmitted data is completely consistent.
Seven-layer structure model of TCP/IP network
Network designers often use the ISO/OSI (International Organization for Standardization/Open System Interconnection) seven-layer model when solving network architectures, each layer of which represents a certain level of network functionality. At the bottom is the physical layer, which represents the physical medium for data transfer, in other words, network cables. Above it is the data link layer, which provides services through a network interface card. The top layer is the application layer, where applications using network services are run.
TCP/IP is equivalent to the ISO/OSI model. When a data unit flows down from a network application to a network interface card, it passes through a column of TCP/IP modules. In each step, the data unit will be packaged with the information required by the peer-to-peer TCP/IP module on the other end of the network. In this way, when the data is finally transmitted to the network card, it becomes a standard Ethernet frame (assuming that the physical network is Ethernet). The TCP/IP software on the receiving side restores the original data for the received application by stripping Ethernet frames and transmitting data upwards across the TCP/IP stack (a best way to understand the essence of TCP/IP work is to use a probe program to observe the information added by different TCP/IP modules in the flowing frames in the network). To outline the role TCP/IP plays in the real world of the web, consider what happens when a web browser using HTTP (Hypertext Transfer Protocol) gets a page of HTML data from a web server connected to the Internet. To form a virtual link to the same web server, the browser uses a high-level software abstractly called a socket. To obtain a web page, it issues the command to the web server by writing an HTTPGET command to the socket. Next, the socket software uses the TCP protocol to issue a byte stream and bit stream containing GET commands to the web server. TCP segments the data and passes each independent segment to the IP module, which converts the data segments into datagrams and sends them to the web server.
If the browser and server are on computers of different physical networks (usually so), the datagrams are transmitted from one network to another until they arrive at the network where the server is located. Finally, the data is transferred to the destination address and reassembled, so that the web server obtains the data backbone by reading its own socket and then views the continuous data flow. For browsers and servers, data is written to the socket at one end and appears like magic on the other end, but this is just various complex interactions that occur below, creating the illusion that data is seamlessly transmitted through the network.
This is what TCP/IP does: connect many small networks into one large network. And provide the mutual communication services required by applications on this large network, that is, the Internet.
Introduction to TCP/IP protocol family
The TCP/IP protocol family includes hundreds of mutually related protocols, and protocols with different functions are distributed in different protocol layers. The following are several commonly used protocols:
Telnet (Remote Login): Provides remote login function, and users of one computer can log in to another remote computer, just like operating directly on a remote host;
FTP (File Transfer Protocol): Remote file transfer protocol, allowing users to copy files on the remote host to their own computer;
SMTP (Simple Mail transfer Protocol): a simple postal transmission protocol used to transmit emails;
NFS (Network File Server): a network file server that allows multiple computers to transparently access each other's directories;
UDP (User Datagram Protocol): User data packet protocol, which is located in the transport layer like TCP and is used in conjunction with IP protocol, eliminating the packet header when transmitting data, but it cannot provide retransmission of data packets, so it is suitable for transmitting shorter files.
TCP/IP protocol (Transfer Controln Protocol/Internet Protocol) is called transmission control/internet protocol, also known as network communication protocol. This protocol is the basis of the Internet international network.
TCP/IP is the basic communication protocol used in the network. Although TCP/IP includes two protocols, Transmission Control Protocol (TCP) and Internet Protocol (IP), TCP/IP is actually a set of protocols, which includes hundreds of protocols with various functions, such as remote login, file transfer and email, etc. The TCP protocol and IP protocol are two basic and important protocols to ensure the complete transmission of data. It is usually said that TCP/IP is an Internet protocol family, not just TCP and IP.
Data transmission
The basic transmission unit of the TCP/IP protocol is datagram. The TCP protocol is responsible for dividing the data into several data packets and adding a packet header to each packet (like adding an envelope to a letter). The packet header has a corresponding number to ensure that the data can be restored to the original format at the data receiver. The IP protocol adds the host address of the receiver on each packet header, so that the data can find the place you want to go (just as if the address is written on the envelope). If data is lost, data distorted, etc. occur during the transmission process, the TCP protocol will automatically require data to be retransmitted and regroup the packet. In short, the IP protocol ensures the transmission of data, and the TCP protocol ensures the quality of data transmission.
The transmission of TCP/IP protocol data is based on the four-layer structure of the TCP/IP protocol: application layer, transmission layer, network layer, and interface layer. When data is transmitted, a packet header must be added to the data every time it passes through one layer. The data in it is for the same layer protocol at the receiving end. On the receiving end, the used packet header must be removed every time it passes through, so as to ensure that the format of the transmitted data is completely consistent.
Seven-layer structure model of TCP/IP network
Network designers often use the ISO/OSI (International Organization for Standardization/Open System Interconnection) seven-layer model when solving network architectures, each layer of which represents a certain level of network functionality. At the bottom is the physical layer, which represents the physical medium for data transfer, in other words, network cables. Above it is the data link layer, which provides services through a network interface card. The top layer is the application layer, where applications using network services are run.
TCP/IP is equivalent to the ISO/OSI model. When a data unit flows down from a network application to a network interface card, it passes through a column of TCP/IP modules. In each step, the data unit will be packaged with the information required by the peer-to-peer TCP/IP module on the other end of the network. In this way, when the data is finally transmitted to the network card, it becomes a standard Ethernet frame (assuming that the physical network is Ethernet). The TCP/IP software on the receiving side restores the original data for the received application by stripping Ethernet frames and transmitting data upwards across the TCP/IP stack (a best way to understand the essence of TCP/IP work is to use a probe program to observe the information added by different TCP/IP modules in the flowing frames in the network). To outline the role TCP/IP plays in the real world of the web, consider what happens when a web browser using HTTP (Hypertext Transfer Protocol) gets a page of HTML data from a web server connected to the Internet. To form a virtual link to the same web server, the browser uses a high-level software abstractly called a socket. To obtain a web page, it issues the command to the web server by writing an HTTPGET command to the socket. Next, the socket software uses the TCP protocol to issue a byte stream and bit stream containing GET commands to the web server. TCP segments the data and passes each independent segment to the IP module, which converts the data segments into datagrams and sends them to the web server.
If the browser and server are on computers of different physical networks (usually so), the datagrams are transmitted from one network to another until they arrive at the network where the server is located. Finally, the data is transferred to the destination address and reassembled, so that the web server obtains the data backbone by reading its own socket and then views the continuous data flow. For browsers and servers, data is written to the socket at one end and appears like magic on the other end, but this is just various complex interactions that occur below, creating the illusion that data is seamlessly transmitted through the network.
This is what TCP/IP does: connect many small networks into one large network. And provide the mutual communication services required by applications on this large network, that is, the Internet.
Introduction to TCP/IP protocol family
The TCP/IP protocol family includes hundreds of mutually related protocols, and protocols with different functions are distributed in different protocol layers. The following are several commonly used protocols:
Telnet (Remote Login): Provides remote login function, and users of one computer can log in to another remote computer, just like operating directly on a remote host;
FTP (File Transfer Protocol): Remote file transfer protocol, allowing users to copy files on the remote host to their own computer;
SMTP (Simple Mail transfer Protocol): a simple postal transmission protocol used to transmit emails;
NFS (Network File Server): a network file server that allows multiple computers to transparently access each other's directories;
UDP (User Datagram Protocol): User data packet protocol, which is located in the transport layer like TCP and is used in conjunction with IP protocol, eliminating the packet header when transmitting data, but it cannot provide retransmission of data packets, so it is suitable for transmitting shorter files.