Layer: 1) Physical layer Phase of Message Processing: d) Organize the data into bits Layer: 2) Data Link layer Phase of Message Processing: c) Organize the data into frames Layer: 3) Network layer Phase of Message Processing: b) Organize the data into packets Layer: 4) Transport layer Phase of Message Processing: a) Organize the data into segments The OSI model divides the networking process into seven layers, each representing a different step of the transmission chain. Each layer has its own function and is responsible for well-defined tasks. User data passes sequentially from the highest layer down through the lower layers until the device transmits it externally. The lowest layer, the physical layer, converts the data into bits that can be sent over a physical medium. The second layer, the data link layer, organizes the bits into frames that can be transmitted over a link between two nodes. The third layer, the network layer, organizes the frames into packets that can be routed across a network of nodes. The fourth layer, the transport layer, organizes the packets into segments that can provide reliable and error-free communication between two end points12. Reference: 1 https://www.linode.com/docs/guides/introduction-to-osinetworking-model/ 2 https://en.wikipedia.org/wiki/OSI_model