Encapsulation (networking)

Under the Data encapsulation is the process in the OSI model and the TCP / IP reference model, the data to be sent in the header ( and possibly trailer ) of the respective layers added. In the OSI model, this concerns the datagrams of the layers 2 to 4, the encapsulated (packaged) are.

Encapsulation process of layer 4 to 2 in the OSI model

By the layers 7-5, only one data stream to the layer 4 passes on the fourth layer, the data stream is divided into data segments. This type of encapsulation on the fourth layer is called segmentation. In addition, the data segment is addressed with a source and destination port number. After segmentation, the data segment is transmitted to the third layer.

On the third layer, the data segment of the fourth layer is encapsulated in a data packet of the third layer. Addressed is this data packet with an IP address. What is provided is a data segment packed into a data packet. This is then forwarded to the second layer.

The second layer receives as a datagram, the data packet with the data segment contained therein, and it encapsulates ( data packet ) in a data frame. This data frame is provided with a MAC address and forwarded to layer 1, which converts the data frames in the physical and binary number system.

Entkapselungsprozess layer 2 to 4 in the OSI model

The layer 1 is replaced by zeros and ones, and a again molded from data frame that is passed to the layer 2. There, the protocol elements be removed. What remains is a data packet that is passed to layer 3. There, the layer 3 protocol elements are removed and directed the then existing data segment at layer 4. Layer 4 analyzed by the port number, which is at the service of the contents of the data segment being addressed. Subsequently, the data stream is passed to the higher layers.