Understanding network model TCPIP model

Network protocol

Network protocol is a rule established for data exchange in computer network 、 A set of standards or conventions .
Common protocols are ：TCP/IP agreement 、IPX/SPX agreement 、NetBEUI agreement   etc. .
TCP/IP agreement   Undoubtedly the most important of the three agreements , As the basic protocol of the Internet , It's impossible to get online without it , Any operation related to the Internet is inseparable from TCP/IP agreement .

TCP/IP agreement

TCP/IP A protocol is a collection of protocols .  Internet protocol is a network communication model , And a whole family of network transmission protocols , For the Internet infrastructure . It is often called TCP/IP Protocol family , abbreviation TCP/IP. Because the two core protocols of the protocol family ：TCP（ Transmission control protocol ） and IP（ Internet protocol ）, Is the first standard adopted by the family .

TCP Use three handshake protocol to establish connection . Three handshakes complete ,TCP The client and server successfully established the connection , It's time to start transmitting data .

IP agreement

A protocol that specifies a network address , be called IP agreement . The address it defines , This is called IP Address .
IP Realize two basic functions ： Addressing and segmentation .IP There are two main functions of the agreement , One is to assign... To each computer IP Address , The other is to determine which addresses are in the same subnet .

TCP agreement （ Transmission control protocol ）

UDP The advantage of the protocol is that it's simpler , Easy to implement , But the disadvantage is poor reliability , Once the packet is sent , It's impossible to know if the other party has received . To solve this problem , Improve network reliability ,TCP The agreement was born .
TCP The protocol ensures that data is not lost . Its disadvantage is that the process is complex 、 Difficult to achieve 、 Consume more resources .

In order to ensure that the information can ensure accurate arrival ,TCP It adopts the famous three times handshake strategy

IP The agreement is to find the detailed address of the other party ,TCP The protocol is to safely transmit data to each other .

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HTTP agreement （ Hypertext transfer protocol ）

HTTP Protocol is the most widely used network protocol on the Internet , be-all WWW Documents must comply with this standard .HTTP Is a client and server-side request and response standard （TCP）, It is built on TCP An application over the protocol .

Read more →：HTTP agreement

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Network reference model

1、OSI Reference model （ Open Systems Interconnection Reference Model ）

Network layer 7 protocol

application layer	File transfer , E-mail , File service , Virtual terminal	TFTP,HTTP,SNMP,FTP,SMTP,DNS,Telnet
The presentation layer	Formatting Data , Code conversion , Data decryption
The session layer	To release or establish contact with other contacts
Transport layer	Provide end-to-end interfaces	TCP,UDP
The network layer	Routing packets	IP,ICMP,RIP,OSPF,BGP,IGMP
Data link layer	Transmit frames with addresses , Error detection function	SLIP,CSLIP,PPP,ARP,RARP,MTU
The physical layer	To transmit data on physical media in the form of binary data	ISO2110,IEEE802

2、TCP/IP Reference model （ Simplified seven layers OSI Model ）

Network four layer protocol ： Network access layer 、 The Internet layer 、 Transport layer （ Host to host ）、 And application layer .

OSI It's a theoretical network communication model , and TCP/IP It's the actual network protocol .