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| 2.1 |  | Using a Layered Architectural Model to Describe Data Flow |
| 2.1.4 |  | Decapsulation |

When the interface of an end-system receives data from the physical medium, frames must be extracted from the bit-stream so that the end-system can verify that the destination physical address of the frame equals its own. When the physical address is verified, the packet is decapsulated from the frame control information and the packets logical control information is examined. Data is further decapsulated from packets as needed for use with the target application.

This represents the fourth stage in the layered model of data flow. Data returned to the original sender goes through the same process:

- Stage 1 – Encapsulation
- Stage 2 – Transmission over the physical medium
- Stage 3 – Network devices utilizing control information to deliver data to the appropriate end-system
- Stage 4 – Decapsulation of data as needed for use with the target application