Chapter 1: Understanding the Web and Networking Fundamentals
1. The Web uses a protocol called HTTP (Hypertext Transfer Protocol) as a specification to complete a series of operational processes from the client to the server .
2. Three WWW construction technologies :
① Establish the text markup language HTML.
② Establish the document transfer protocol HTTP.
③ Specify the address (URL) of the document (HTML )
3. The HTTP protocol is a subset of the TCP/IP protocol suite .
4. Protocol: It is a general term for various rules , from the specification of the cable to the selection method of the IP address, the method of finding remote users, the sequence of establishing communication between the two parties, and the steps to be processed when the Web page displays, etc.
5. The collection of all protocols is the TCP/IP protocol .
6. A data packet is the smallest unit of data transmitted by a network .
7. There are so many protocols in the TCP/IP protocol family. For the convenience of management, it is divided into four layers :
①Application layer (rules when providing application services to users, such as FTP file transfer protocol, DNS domain name system, HTTP hypertext transfer protocol)
②Transport layer (the rules of data transmission between two computers , such as TCP Transmission Control Protocol, UDP User Datagram Protocol)
③ Network layer ( the rules for processing data packets flowing on the network, such as which route to transmit data packets, the IP protocol is at this layer)
④ Link layer (the rules of the hardware connecting the network , such as network cards, optical fibers, network cables, etc.)
8. When using the TCP/IP protocol suite for communication, through the layered sequence, the sender starts from the application layer and goes down, and the receiver starts from the link layer and goes up.
9. "IP" is the name of a protocol .
10 "IP address" refers to the address to which a node is assigned . IP addresses may change.
11 "MAC address" refers to the fixed address to which the network card belongs . The MAC address does not change.
12. ARP protocol: It is a protocol used to resolve addresses . According to the IP address of the communicating party, the corresponding MAC address can be found out .
13. TCP protocol: It can divide large pieces of data into small pieces of data, and then confirm whether the data is finally sent to the other party. The three-way handshake strategy appears within the TCP protocol.
14. DNS Protocol: Provides domain name to IP address resolution services . www.qq.com is a domain name (also called the host name HOST in some cases ). The domain name can look up the IP address, and the IP address can also reverse the domain name.
15. URI (Uniform Resource Identifier ), URL (Uniform Resource Locator ) These two are used to identify and locate resources on the network , and URL is a subset of URI.
16. RFC document: A document used to specify the technical standards of the HTTP protocol .