| Layer | Name | Function | Protocols |
|---|---|---|---|
| Layer 7 | Application | To allow access to network resources. | SMTP, HTTP, FTP, POP3, SNMP |
| Layer 6 | Presentation | To translate, encrypt and compress data. | MPEG, ASCH, SSL, TLS |
| Layer 5 | Session | To establish, manage, and terminate the session | NetBIOS, SAP |
| Layer 4 | Transport | The transport layer builds on the network layer to provide data transport from a process on a source machine to a process on a destination machine. | TCP, UDP |
| Layer 3 | Network | To provide internetworking. To move packets from source to destination | IPV5, IPV6, ICMP, IPSEC, ARP, MPLS. |
| Layer 2 | Data Link | To organize bits into frames. To provide hop-to-hop delivery | RAPA, PPP, Frame Relay, ATM, Fibre Cable, etc. |
| Layer 1 | Physical | To transmit bits over a medium. To provide mechanical and electrical specifications | RS232, 100BaseTX, ISDN, 11. |
OSI vs TCP/IP Layer
OSI Diagram
