Introduction to network programming + osi model
1. Basic principles of Internet protocol
- how to communicate
- Communication principle
- Working Mechanism
- http
- smtp
- dns
- ftp
- Douyin Live
2. Master the ability of networking software with open c/s architecture
c client WeChat app
s server WeChat server
3. OSI model
The physical layer transmits data on the physical medium in the form of binary data ISO2110
data link layer transmits frames with addresses and error detection ARP MTU
----------------------- ------------ The above two are collectively referred to as the link layer
Network layer routes packets IP BGP [routing protocol] IGMP OSPF RIP
transport layer provides end-to-end interface, TCP UDP
The session layer releases or establishes a session connection with other nodes
. The presentation layer data formatting code conversion data encryption
Application layer file sharing, mail, web
------------- The above three are collectively referred to as the application layer
4. How to send a message to the other party's computer
When the message is sent [application layer]
message + TCP header [transport layer]
message + TCP header + IP header [network layer]
message + TCP header + Ethernet header [data link layer]
arrives at [physical layer]
after reaching the other party, in turn unpack
