I’m taking a course on the basics of open networks and my tutor Koos Baas used a great letter/envelope analogy to describe the addition/removal of PDU PCI headers as data moves down and up the stack. I wondered what other analogies might work to describe a user sending a message to another. I remembered the doll I had and took a snapshot:
The smallest doll could be thought of as the data from the sender’s application. The largest doll could be thought of as a frame, just before being turned into bits for the physical layer. Shortly thereafter, the unpacking begins until the recipient gets the smallest doll at their application layer.
To my sister Lesley who gave me this gift I say, spasiba!