Human-computer interaction layer, where applications can access the network services.
Software to send/receive information and present meaningful data to users.
Used by end-user software such as web browser and email clients.
Protocols: HTTP, FTP, POP, SMTP, DNS
6 Presentation Layer
Ensures that data is in a usable format + encryption
Prepares data for the application layer. Defines encoding between devices, encryption, and compression.
Passes data between application and session layers.
5 Session Layer
Maintains connections and controls ports and sessions (comm channels between devices)
4 Transport Layer
Transmits data using transmission protocols including TCP and UDP
Breaks/reassemble session data into/from segments. Also carries out flow and error control.
3 Network Layer
Decides which physical path the data will take
Breaks segments into network packets, and reassembling the packets on the receiving end. Also routes packets by discovering the best path across a physical network. Typically uses IP addresses to route packets to destination.
2 Data Link Layer
Defines the format of data on the network.
Establishes and terminates connection between two physically connected nodes on a network. Break packets into frames and send them from source to destination.
1 Physical Layer
Transmits raw bit stream over the physical medium.
Responsible for physical medium (cable wireless) connecting network nodes.
It defines the connector, electrical cable or wireless technology connecting devices. Transmission of raw data.