Computer network reference model
ISO five layers: application layer, transport layer, network layer, data link layer, physical layer
Application layer: HTTP,FTP,TFTP,SMIP,SNMP,DNS and other (data) computers
Transport layer: tcp Transmission Control Protocol, udp user data Protocol (Transport Protocol, Port) Segment (segment) Firewall
Network layer: icmp,igmp,IP,ARP,rarp (Network Protocol) IP packet (packet) Router
Data link layer: protocol Mac data frame (frame) switch defined by the underlying network
Physical layer: bitstream (bits) network card
The seventh layer divides the application layer into application layer, presentation layer and session layer.
