2. What is Encapsulation?
Encapsulation is used to describe the process of adding Headers and Trailers around
data being sent through a network. This applies to the TCP/IP (Transmission Control
Protocol/Internet Protocol) and the OSI network protocols however, we will be covering
TCP/IP.
For TCP/IP encapsulation there are four layers for encapsulation and four layers for
de-capsulation.
Application Layer
Transport Layer
Internet Layer
Network Access Layer
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3. For example, you would like to send a gift to a friend.
The application layer wraps the gift, the transport layer places
gift in a bag, the internet layer then packs the gift into a box
then the network access layer transports the gift.
The TCP protocol breaks data like a message or a photo into many,
much smaller packets.
The internet protocol defines the structure of the packet being
encapsulated to be delivered. The addressing methods for labelling
the source and destination of the packets in the datagram. is part of
the IP (Internet Protocol).
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4. To clarify, encapsulation involves moving data through layers from
upper level (Application Layer) to lower level (Network Access
Layer).
As the data moves through the layers bundles of information called
headers and trailers are added. Header is the supplemental data
placed at the beginning of a block of information when it’s
transmitted.
This supplemental data is used at the receiving side to extract data
from the encapsulated data packet.
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6. What is De-capsulation?
The reverse process of encapsulation (or de-capsulation) 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.
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7. Names of different network data
packets
The format of the data packet generated at different layers is
different, and known by different names.
The data packet created at the Application layer is known as a
"MESSAGE".
the Transport Layer contains two important protocols: TCP
(Transmission Control Protocol) and UDP (User Datagram
Protocol). TCP is more reliable but consumes more resource. UDP is
less reliable but consumes fewer resources than and is faster
than TCP.
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8. Names of different network data
packets
The Application layer message is again encapsulated at
the Transport Layer. If the protocol used at the Transport Layer is TCP,
the data packet is known as a "TCP SEGMENT". If the protocol used
at the Transport layer is UDP, the data packet is known as a "UDP
DATAGRAM".
The data packet created at the Internet layer by Internet Protocol,
which again encapsulates the Transport layer segment/datagram, is
known as an "IP DATAGRAM".
The data packet at the Network Access layer, which encapsulates
and may subdivide the IP Datagram, is known as a "FRAME"
(generally Ethernet Frame). The Frame is converted into a bit-stream
at the lowest sub-layer of the Network Access layer and then
placed on medium.
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9. Terminology
Frame, Packet, Segment, Datagram
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Frame - the term "frame" refers to the encapsulated data defined by the Network Access
layer. A frame can have a header and a trailer that encapsulate a data section.
Packet - the term "packet" is used to describe the encapsulated data defined by the Internet
layer. A packet can have a header with the source and destination IP addresses.
Segment - the term "segment" describes encapsulated data defined by the Transport layer. A
segment can have a header with information such as source and destination port numbers,
sequence and acknowledgment numbers, etc.
Datagram - refers to the Headers and raw data (payload) of the data being transported.
