OSI Model
Network Layers and Protocols
OSI Model
| Layer Name | Purpose | Protocols | mnemonic |
| Application | Human Machine Interface – Where data is entered, Connects application to network | DNS,HTTP,SMTP,POP3,FTP | All |
| Presentation | Data coded into 1s and 0s, or decoded, depending on file format | JPEG,MIDI,TIFF,SSL,SSH | People |
| Session | Where secure sessions created, authentication takes place | NetBIOS, | Seem |
| Transport | Error checking it conducted here. Chooses which transport protocol to use | TCP,UDP,End-toEnd | To |
| Network | Addressing and Routing | IPV4,IPV6,IPSec | Need |
| Data-Link | This layer is where the data is prepared for sending | Ethernet,PPP,ATM | Data |
| Physical | Data is physically sent along a wire, fiber optic cable or radio waves. | Ethernet, USB, Bluetooth,IEEE802.11 | Processing |
Activity – Watch the video below and fill out the worksheet (in the resources section) as you go through.
Packet Switching
Packet Switching
When large packets of data are send over the internet, they are split down in to smaller packets, with each packet being given a packet order number, and sent over the internet independently. The packets travel separately over the network, sometimes taking separate paths, and the packets are then reassembled at the other end. This allows for faster data transfer.