This document discusses the four layers of the TCP/IP model and how they coordinate with each other. It explains the processes of encapsulation and decapsulation as data moves between layers. Encapsulation involves each layer adding a header to data packets as they move down the stack, while decapsulation is the reverse process of removing headers as packets move up the stack at their destination. Figures and references are provided to illustrate these TCP/IP concepts.

2. Contents:
• Four Layers of TCP/IP Model
• How the TCP/IP Layers Coordinates
• Encapsulation
• Decapsulation
• Bibliography

3. Four Layer of TCP/IP
Model
Figure 1. TCP/IP basic stack
functionalities.
Note. From An Information on
The TCP/IP. (n.d.). Retrieved
from
http://www.tenouk.com/Module
42.html

4. TCP/IP Video

5. How The TCP/IP Layers Coordinates
Figure 2. TCP/IP Layer Coordinates
Note. From Internetworking Using
TCP/IP. (2012). Computer
Networking. Retrieved from
http://computernetworks-jw.
blogspot.co.nz/

6. Encapsulation
When data moves from upper layer to lower level of
TCP/IP protocol stack (outgoing transmission) each layer
includes a bundle of relevant information called a header
along with the actual data.
The data package containing the header and the data
from the upper layer then becomes the data that is
repackaged at the next lower level with lower layer's
header.
Header is the supplemental data placed at the beginning
of a block of data when it is transmitted. This
supplemental data is used at the receiving side to extract
the data from the encapsulated data packet.
This packing of data at each layer is known as data
encapsulation.
Figure 3.Encapsulation
Note. From TCP/IP Data Encapsulation and
Decapsulation. (2008). Omnisecu.com. Retrieved
from http://www.omnisecu.com/tcpip/tcpip-encapsulation-
decapsulation.php

7. Decapsulation
The reverse process of encapsulation (or decapsulation)
occurs when data is received on the destination computer.
As the data moves up from the lower layer to the upper
layer of TCP/IP protocol stack (incoming transmission),
each layer unpacks the corresponding header and uses
the information contained in the header to deliver the
packet to the exact network application waiting for the
data.
Figure 4. Decapsulation
Note. From TCP/IP Data Encapsulation and Decapsulation. (2008). Omnisecu.com. Retrieved
from http://www.omnisecu.com/tcpip/tcpip-encapsulation-decapsulation.php

8. Encapsulation and
Decapsulation
Figure 5. Encapsulation and Decapsulation.
Note. From Chapter 5 - Encapsulation and De-encapsulation Process.(2012) . Techleets. Retrieved from
http://www.techleets.com/2012/09/chapter-5-encapsulation-and-de.html

9. Bibliography
Encapsulation and Decapsulation. (2012). Retrieved from
http://www.techleets.com/2012/09/chapter-5-encapsulation-and-de.html
TCP/IP Data Encapsulation and Decapsulation. (n.d.). Retrieved from
http://www.omnisecu.com/tcpip/tcpip-encapsulation-decapsulation.php
Mistertentpole (2007, March 11). TCP/IP An animated Discussion [Video File].
Retrieved from https://www.youtube.com/watch?v=RbY8Hb6abbg