Difference between encapsulation and decapsulation

Whenever we share data and information, it is very important to make sure the data reaches its destination; it is not lost somewhere through its path during transmission. If the communication is secure, then the time consumed will also be less.

But before proceeding we must know that data encapsulation and decapsulation help in working and processing the data transmission. It provides reliability and security to the data that is being transferred from the sender to the receiver so that no unwanted access can happen. It also helps in hiding the complex details of the transmission system so that no error can occur at the time of transmission.

What is Encapsulation?

Encapsulation is adding headers and trailers to data packets (small units of data) for transmitting information which helps in the transfer of packets with their dedicated path to reach their destination in a network.

Process of Encapsulation:

  • As we know there is a 7-layer OSI model which defines the fundamental structure of Networking. A source computer sends a message (sender) at layer 7 which is an application to the destination (or receiver) at level 1 which is the physical layer. So we can say, encapsulation starts at the transport layer (layer 4). When it takes the input and is divided into packets. These packets are attached with a header and trailer to inform them about where data is forwarding.

  • Further, the Transport Layer also adds some additional information which is called the header segment. The entire information comprises “segment”. It then goes to its next layer.

  • Now, The Network Layer later adds headers and trailers to the segment for further transmission in the layer. Now it has become a new entity called “Datagrams”.

  • Again, the next layer (Data Link Layer) also adds additional information to the data and it finally reaches its final layer which is the Physical Layer. It also adds the final information to the input data, eventually, the process of encapsulation terminates here.

  • Now we see that the name changes when it moves down the layer to its destination. The data eventually at the physical layer is called bits.

So this is the overall process it is just adding “Headers” and “Trailers” after layer 4 (of the OSI model) to the input data for adding more information about where this data should transmit in the next layer until it reaches the last layer (Physical Layer).

What is Decapsulation?

Decapsulation is the opposite process of encapsulation. It is the process of removing those ‘Headers’ and ‘Trailers’ in front of the data input when it reaches its destination. This process follows the opposite direction of the OSI model which is followed by the encapsulation process.

It will remove all those headers and trailers from the data so the data will get back to its original form at the end of the layer or we can say when it reached the destination.

Process of Decapsulation

  • First, the encapsulated data at the physical layer will be decapsulated and converted to frames, and sent to the next upper layer.

  • Next, it will receive the at the data link layer, it will also check for the MAC address as if it matches or not. If no mistake is found then its data will be decapsulated and the packet would be forwarded to the Transport Layer.

  • Now the network layer would get the data and again decapsulation will happen and it will move forward the data to the Transport Layer.

  • Now the data is a datagram and it will get decapsulated at the Transport layer.

  • After getting through all the layers of the OSI model it will ultimately reach the receiver.

So, this is the overall process of decapsulation in the Network.

Difference between Encapsulation and Decapsulation

Let’s now discuss the difference between Encapsulation and Decapsulation and they differ from each other −

Basis of Differences



OSI model movement

Data would traverse from the upper layer to the lower layer destination through nodes.

Data would traverse from the lower layer to the upper layer in the OSI model.

Effect on Headers and Trailers

It adds a header and trailer to the data.

It removes the header and trailer from the data.

Device specification

It happens at the source computer.

This process happens at the destination computer.

Sequence of process

This is the initial step of encoding.

It is followed by encapsulation for decoding.


It secures and tags the original data to make transmission easier

It extracts the original existing data or message.

Now as we have seen the difference and its functionality, we shall move to our conclusion on the topic.


In this article, we have learned about what is encapsulation and decapsulation, how these work inside the OSI model and what are processes required to do encapsulation and decapsulation. The difference between encapsulation and decapsulation is explained through various points like functionality, device specification and sequence of the process, etc. Although they have the same characteristics with different functionality, both are equally important.

Updated on: 17-May-2023


Kickstart Your Career

Get certified by completing the course

Get Started