Different textbooks may give you different answers to this question. In several I've seen, the "packet" is complete in the data link layer (layer 2) and is known as a 'frame' in the physical layer (layer 1).
Others may indicate a packet is the result of the physical layer (layer 1). In other descriptions the terms packet and frame are interchanged in the layer 1 and 2 of the OSI model.
LAPD
Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.
Packet switching breaks the original data into smaller segments per packet before transmission. This is done in the layer 4 transport layer of the OSI model.
Data link layer
Layer 3,4 and 7
Layer 2 (Data Link Layer) http://compnetworking.about.com/cs/internetworking/g/bldef_bridge.htm
The Network Layer
It depends on which textbook you are reading; some textbooks state that the frame is constructed in the data link layer (layer 2) and transmitted out the physical layer as a packet. Some other textbooks will say that the packet is created in layer 2 and transmitted out the physical layer as a frame.
Application Layer
the network layer --> check your question. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ That is totally not the right answer, how about you actually read the book for the course. It is the data link layer that does encapsulation. I agree - its the Data Link Layer which encapsulates the Network layer...NOT the Network Layer.
Data Link Layer
TELNET