Hi, you should have a good understanding of the OSI model when you discuss encapsulation. The top 3 layers pass their data down to the transport layer, the transport layer encapsulate the data into a "segment". The segment is passed down to the network layer, the network layer add the IP and routing and then creates a "packet" the packet is passed down to the datalink layers which adds layer 2 addressing and protocols and creat a "frame". the frame is passed down to the physical layer which places the information from the frame onto the wire in "bits".

All of this is reversed on the receiving computer. HTH

application

presentation

session

transport = segment

network = packet

datalink = frame

physical = bits