Python Learning---network programming 1217[all]

OSI seven-layer model: physical layer, Data link layer, network layer, transport layer, session layer, expression layer, application layer

Application layer: Tftp,http,snmp,ftp,smtp,dns,telnet, etc.

Transport Layer: TCP,UDP

Network layer: IP,ICMP,OSPF,EIGRP,IGMP

Data Link layer: SLIP,CSLIP,PPP,MTU

"Pictures from the network"

Network communication Elements :

A:ip Address (1) is used to identify a separate host on the network

(2) IP address = Network address + host address (network number: Used to identify the network/network segment where the host is located. Host number: Used to identify the host in the network)

(3) Special IP address: 127.0.0.1 (local loopback address, reserved address, dotted decimal) can be used to simply test the NIC for failure. Represents the native.

B: Port number: (1) The logical address used to identify the process. Different processes have different port identities.

(2) port: to identify these applications by sending the data to the application specified by the other, the network applications are identified by numbers. To address these numbers conveniently, these numbers are referred to as ports. (This port is a logical port)

C: Transport protocol : rules for communication. For example: TCP, UDP protocol (like two people have to communicate in the same language)

①, udp:user Datagram Protocol User Datagram Protocol

Features: For no connection: the source and destination ports do not need to be connected before transmitting data, each datagram size is limited to 64K (8 bytes), and the unreliable protocol for message. (That is, the data sent is not necessarily received) transmission rate is fast, high efficiency; real life examples: Post Office, real-time online chat, video conferencing ... such as

②, Tcp:transmission Control Protocol Transmission Protocol

Features: Connection-oriented: the need to establish a connection before the transmission of data, a large number of data transmission during the connection process, through the "three-time handshake" to complete the connection, is a safe and reliable protocol, slow transmission speed, low efficiency.

Socket-Server/client programming

Python Learning---socket programming

server-side concurrent chat [Socketserver]

Python Learning---socketserver programming

Remote execution Commands

Python Learning---remote execution commands

Network File Upload

Python Learning---web file upload

Python Learning---network programming 1217[all]