Open Systems Interconnection Reference Model (OSI Model)
A layered abstract description for communications and computer network protocol design.
Seven Layer Model:
- Application layer
- Presentation layer (data representation)
- Session layer (typically unused)
- Transport layer
- Network layer
- Data link layer
- Physical layer
Application Layer
| HyperText Transfer Protocol (HTTP) |
- port 80 (or 8080)
|
| Simple Mail Transfer Protocol (SMTP) |
- port 25
|
| File Transfer Protocol (FTP) |
- port 21
|
| Post Office Protocol version 3 (POP3) |
- port 110
|
| Internet Message Access Protocol (IMAP) |
- port 143
|
| Domain Name System (DNS) |
- port 53
|
| Telnet |
- port 23
|
| Secure SHell (SSH) |
- port 22
|
Transport Layer
- User Datagram Protocol (UDP)
- Transmission Control Protocol (TCP)
Network Layer
- Internet Protocol (version 4) (IP) - 4 * 8 bit 4 × 10^9 unique addresses
- Internet Protocol version 6 (IPv6) - 4 * 16 bit 3.4 × 10^38 unique addresses
Link Layer
- Ethernet
- IEEE 802.11 / Wi-Fi - a standard for Wireless Local Area Network (WLAN)
References