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Yyds dry goods inventory OSI & tcp/ip

2022-07-06 04:29:00 【You0tech】

OSI : Open System Interconnection

      
      
       
        The seventh floor ：  application layer  --->  Network services for applications 
       
       
 The sixth floor ：  The presentation layer  --->  Formatting Data 、 encryption 、 Decrypt 
       
       
 The fifth floor ：  The session layer  --->  establish 、 maintain 、 Manage session connections 
       
       
 The fourth level ：  Transport layer  --->  establish 、 maintain 、 Manage end-to-end connections 
       
       
 The third level ：  The network layer  ---> IP Addressing and routing 
       
       
 The second floor ：  Data link layer  --->  Control the communication between network layer and logistics layer 
       
       
 first floor ：  The physical layer  --->  Bit streaming 
      
      
      
      
       
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first floor ： The physical layer

      
      
       
        The physical layer ： Specify the logistics medium 、 Ethernet cable 、 Optical fiber 、 electric current 、 voltage 、 Network card and other standards 
      
      
      
      
       
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The second floor ： Data link layer

      
      
       
        Data link layer ：MAC Address 、 Switch 
      
      
      
      
       
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The third level ： The network layer

      
      
       
        The network layer ： encapsulation IP Address 、 Router 
      
      
      
      
       
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The fourth level ： Transport layer

      
      
       
        Transport layer ： TCP  or  UDP  Port number 
      
      
      
      
       
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TCP/IP Model (tcp/ip Protocol stack )

A collection of many Internet protocols , Among them TCP and IP Mainly , The set of these protocols is called TCP/IP Protocol stack .

      
      
       
        The fifth floor ： application layer 
       
       
 The fourth level ： Transport layer 
       
       
 The third level ： The network layer 
       
       
 The second floor ： Data link layer 
       
       
 first floor ： The physical layer 
      
      
      
      
       
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Packet structure

On the second floor ：MAC + Three layers ：IP Address + four layers ：TCP、UDP port + high-level ：DATA

Application data + Transport layer ： Data segment

Application data + Transport layer + The network layer ： Data packets

Application data + Transport layer + The network layer + Data link layer ： Data frame

Application data + Transport layer + The network layer + Data link layer + The physical layer ： Data flow ( Bit stream )

TCP UDP

TCP UDP Belongs to the transport layer

Common port numbers

      
      
       
       DNS: UDP 53  TCP 53
       
       
DHCP: UDP 67 68
       
       
FTP: TCP 20 21
       
       
Telnet: TCP 23
       
       
HTTP: TCP 80
       
       
Telnet： TCP 23
       
       
HTTPs： TCP 443
       
       
RDP: TCP 3389
       
       
TFTP: UDP 69
      
      
      
      
       
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