【 Three minutes a day 】OSI Seven layer model


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5395cd79631d81a7dafd3925521e8720.jpeg What is an agreement ?

answer : Agreement, as the name suggests, is negotiation , A legal document made after negotiation .

Layer corresponds to device and protocol

layered

equipment

The transmission unit (PDU)

agreement

application layer

PC


SMTP,FTP,TFTP,DHCP,DNS,SNMP,HTTP,HTTPS,TELNEL

The presentation layer




The session layer




Transport layer

A firewall

Data segment

TCP,UDP,SPX

The network layer

Router

Data packets

IP,ARP,RARP,ICMP,RIP,OSPF,IGMP

Data link layer

Switch

Data frame

STP,PPP

The physical layer

network card

Bit stream

RJ-45,EIA/TIA -568

What is standard ?

answer : The criteria for measuring things , Technology in authoritative testing , A standardized technique developed after practice .

standard :

IEEE-802 LAN standard

IEEE802.3U standard :100MB/S Ethernet

IEEE802.3Z standard :1GB/S Ethernet ( Optical fiber )

IEEE802.3ab standard :1GB/S Ethernet ( Twisted pair )

IEEE802.3ae standard :10GB/S Ethernet

IEEE802.3ba standard :100GB/S Ethernet


WLAN standard

IEEE802.11a standard :54MB/S

IEEE802.11b standard :11MB/S

IEEE802.11g standard :54MB/S

IEEE802.11n standard :300MB/S

IEEE802.11ac standard :1GB/S


notes : Standard Organization :OSI International Organization for Standardization ,ANSL National Bureau of Standardization ,ITU-T international telecommunications union ,IEEE The Institute of Electronic Engineering .