The OSI and TCP/IP Networking model

<The OSI Model>
  • Layer 7: Application -End users interact with the network; Data integrity, privacy, and the presence of absence or absence of error recovery natures. (e.g. Gmail, Facebook, Twitter)
  • Layer 6: Presentation - Data presentation, data encryption (e.g. SSL/TLS)
  • Layer 5: Session - The manager of data transfer process; Session creation, maintenance, and teardown of the communications (e.g. Tunneling protocols)
  • Layer 4: Transport -The "post office: layer (e.g. TCP segment, UDP datagram)
  • Layer 3: Network - Routing layer (IP address, router, packet)
  • Layer 2: Data Link - Switching layer (Frame, MAC address, EUI-48, EUI-64, Switch)
  • Layer 1: Physical -Network cabling 
When I send a photo to my friend A, the data is in an original format until it reaches to layer 4 where data gets segmented into segments and then at Layer 3 it becomes packets and at layer 2 it becomes frames and then finally it becomes bits 1s and 0s. 

<The TCP/IP Model>
  • Application: FTP, BOOTP, TFTP, DNS, HTTP(S), TSL/SSL, VoIP, SSH, POP3, IMAP4, NTP, Telnet, SMPT, SNMP
  • Transport: TCP, UDP
  • Internet: IPv4, IPv6, ICMP, IGMP
  • Link: ARP


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