The document describes how Janet sends an email with a photo attachment to her cousin in Australia using the 7 layers of the OSI model. It explains each layer's role - the application layer allows Janet to compose the email, the presentation layer formats the data, the session layer manages the connection, the transport layer segments the data, the network layer adds IP addresses, the data link layer adds physical addresses, and the physical layer converts the data to signals for transmission. The email travels down the layers of Janet's computer, is transmitted across networks, and travels back up the layers of the cousin's computer, where it is reassembled and received by the cousin's email application.
