OSI Model Table
Since I am in the throws of recertifying my CompTIA Security+ status, I decided to post my review of the OSI model. This information is all pretty easy to find, however I wanted make sure I tied together not only the layers but the technologies that are apart of each layer when possible.
| Layer | Name | Unit | Examples | Description |
| L1 | Physical | bit | wire,fibre | Layer 1 is the physical medium of data transfer, most commonly copper, fibre, or airwaves by todays standards. |
| L2 | Data-Link | frame | switch/hub,NIC,MAC address | Layer 2 facilitates data transfer over physical medium between devices on the same network/LAN, commonly referred to as switching |
| L3 | Network | packet | router/gateway,Internet Protocol(IP) | Layer 3 facilitates data transfer between different IP networks or LANs, commonly known as routing... |
| L4 | Transport | TCP Segments/UDP datagrams | Transmisson Control and User Datagram Protocols (TCP/UDP) | Layer 4 is responsible for maintainig the end-to-end virtual circuits created between devices when sending or receiving data |
| L5 | Session | Messages | SQL,SSL | Layer 5 maintains the unique sessions and certificates created between applications moving up and down the stack |
| L6 | Presentation | Messages | encryption,compression | Layer 6 translates and formats data into whatever form the next layer requires, be that up to Application at the end of transmission, or down to Session at the beginning... |
| L7 | Application | Messages | email,FTP,SSH | Layer 7 is where message creation begins or ends, depending on whether one is a sender or receiver of a message. |
References:
http://www.howtonetwork.org/design/ccda/chapter-1-network-fundamentals
CompTIA Security+ SY0-401 3rd Edition, ISBN-13: 978-0-7897-5333-5