The Open Systems Interconnect (OSI) 7 layer model is the foundation stone for data communications. The OSI Reference model defines seven layers that describe how applications running upon network-aware devices may communicate with each other. The model is generic and applies to all network types, not just TCP/ IP, and all media types, not just Ethernet. An excellent tutorial is available from PC Network Advisor.

It is important to understand the function of each layer. Knowing the order in which each layer appears in the stack is fundamental to understanding its role.

A mnemonic is a memory aid, designed to make it easier to remember lists of data. A typical technique involves taking the first letter of each word in the list, and creating a sentence based on those letters.

This technique is often used to help people remember the order of each layer in the OSI 7 layer model. Sometimes the mnemonic is created from the bottom up, and sometimes from the top down. So the options are:-

The mnemonic traditionally suggested by IT trainers is:

All People Seem To Need Data Processing

Fortunately the IT world is populated by people with a bit more imagination, and consequently there are many mnemonics for the OSI 7 layer model that are much more entertaining. Here is a selection.

Princess Diana Never Tried Screwing Prince Andrew
Please Do Not Take Sales People's Advice
Philys Did Networking Till She Passed Away
American Presidents Should Try New Dating Practices
All Penguins Stand Too Near Deep Pools
Angus Prefers Sausages To Nibbling Dried Pork
A Pathetic Silly Trick Never Does Please
People Don't Need This Stuff Presented Anyway
Programmers Do Not Throw Sausage Pizza Away
Arse Pounders Seem To Neglect Delicious Pussy
All Parents Should Teach New Dads Parenting
Apply Proper Sense To Network Data Path
People Don't Need To Study Protocol Analysis
Please Do Not Touch Steve's Pet Alligator
Phil Donahue Never Televises Sick People Anymore
Please Dear, Not Tonight, Soft Penis Already
All People Studying This Need Drastic Psychotherapy
People Design Networks To Send Packets Accurately
Australian Post Sucks They Never Deliver Parcels
Philosophers Deign Not To Solipstically Ponder Anachronisms
Please Don't Network These Stupid People Again
Any Person Standing Totally Nude Doesn't Perspire
All Pussy Seems To Need Douching Periodically

If you have your own amusing mnemonic for the OSI 7 layer model which you would like to be included here, please email it to contact@ethernettraining.com