This table shows the OSI model layers and the components that operate at each layer.
| OSI Layer | Purpose | TCP/IP Layer | Protocol | Packet Data Unit | Address | Device | Troubleshoot |
|---|---|---|---|---|---|---|---|
| Application | Interface (API) | Application | HTTP, SMTP, etc. | Message | - | - | Wireshark |
| Presentation | Formatting, Encryption, Compression | Application | HTTP, SMTP, etc. | Message | - | - | Wireshark |
| Session | Authentication, Authorization | Application | HTTP, SMTP, etc. | Message | - | Gateway | NSLOOKUP, NBTSTAT, Wireshark |
| Transport | Reliability | Transport | TCP, UDP | Segment (TCP), Datagram (UDP) | Port | Firewall | TELNET, NETSTAT, Wireshark |
| Network | Addressing, Routing | Internet | IP, ICMP | Packet | IP Address | Router | IPCONFIG, PING, TRACERT, Wireshark |
| Data Link | Logical Link Control, Media Access Control | Link | Ethernet, Wi-Fi, PPP, etc. | Frame | MAC Address | Switch, Bridge, Access Point | Lights on device, ARP, Wireshark |
| Physical | Transmission | Link | CAT 5, RJ-45, etc. | Bit | - | Hub, NIC, Cable, Wireless | Lights on device |
One easy way to remember the OSI layer is to think:
A - All
P - People
S - Seem
T - To
N - Need
D - Data
P - Processing
Another popular acrostic to remember OSI layers names is (inferring that it is required to attend classes to pass networking certification exams):
A - Away
P - Pizza
S - Sausage
T - Throw
N - Not
D - Do
P - Please
Suggestions from David Bombal (7 to 1):
A - All
P - People
S - Sleeping
T - Through
N - Networking
D - Don't
P - Pass
Going the opposite way (1-7):
P - Please
D - Do
N - Not
T - Teach
S - Students
P - Pointless
A - Acronyms
Going the opposite way, widely used in India Schools (1-7):
P - Please
D - Do
N - Not
T - Take
S - Sales
P - Person's
A - Advice