16
Data is basically
originated
by applications
and transmitted
to another
destination. As
the
data
is
passed
down
through
TCP/IP
layers
from
application
to
datalink
layers, data
will be encapsulated and every relevant protocol
will attach control
information by
adding
the
form
of
header
in
each
data
or
packet.
First,
user
data
is
generated as
application byte stream.
Application
layer
gives the
first application
header
to
the packet before
it
passes
to
the
next
layer. In
application layer,
it
adds
information
into
the
HTTP
header.
In transport
layer,
TCP
adds
its
header
before
it
hands over
it
to
IP
layer.
IP
in
network
access
layer
also
appends
information header
and
create
IP
datagram.
Eventually,
IP
datagram
is
represented
in
network
access
layer
before
it
is
transmitted across
the
network
to
its
destination.
It
goes
through
the
data
link
layer
in
which
the
IP
datagram
is
appended
with
the
last
information
header
and
ready
to
be
transmitted. After data or
packet
is
received
at
destination,
and
moving
up
through
the
layers, relevant packet
will be
stripped off
and each relevant
information attached to
the
packet as
header will be read, so that it allows each protocol to communicate with other
protocol with the same layer on the other computers in logical manner effectively.
Figure 3 – Encapsulation process of TCP/IP packet headers
 |