<s>
In	O
the	O
seven-layer	O
OSI	O
model	O
of	O
computer	B-Architecture
networking	I-Architecture
,	O
the	O
presentation	B-Application
layer	I-Application
is	O
layer	B-Application
6	I-Application
and	O
serves	O
as	O
the	O
data	O
translator	O
for	O
the	O
network	B-Architecture
.	O
</s>
<s>
Within	O
the	O
service	O
layering	O
semantics	O
of	O
the	O
OSI	O
network	B-Architecture
architecture	O
,	O
the	O
presentation	B-Application
layer	I-Application
responds	O
to	O
service	O
requests	O
from	O
the	O
application	B-Application
layer	I-Application
and	O
issues	O
service	O
requests	O
to	O
the	O
session	B-Application
layer	I-Application
through	O
a	O
unique	O
presentation	O
service	O
access	O
point	O
(	O
PSAP	O
)	O
.	O
</s>
<s>
The	O
presentation	B-Application
layer	I-Application
ensures	O
the	O
information	O
that	O
the	O
application	B-Application
layer	I-Application
of	O
one	O
system	O
sends	O
out	O
is	O
readable	O
by	O
the	O
application	B-Application
layer	I-Application
of	O
another	O
system	O
.	O
</s>
<s>
In	O
theory	O
,	O
it	O
relieves	O
application	B-Application
layer	I-Application
protocols	O
of	O
concern	O
regarding	O
syntactical	O
differences	O
in	O
data	O
representation	O
within	O
the	O
end-user	O
systems	O
.	O
</s>
<s>
An	O
example	O
of	O
a	O
presentation	O
service	O
would	O
be	O
the	O
conversion	O
of	O
an	O
extended	B-Language
binary	I-Language
coded	I-Language
decimal	I-Language
interchange	I-Language
code	I-Language
(	O
EBCDIC-coded	O
)	O
text	O
computer	B-Operating_System
file	I-Operating_System
to	O
an	O
ASCII-coded	O
file	O
.	O
</s>
<s>
If	O
necessary	O
,	O
the	O
presentation	B-Application
layer	I-Application
might	O
be	O
able	O
to	O
translate	O
between	O
multiple	O
data	O
formats	O
using	O
a	O
common	O
format	O
.	O
</s>
<s>
In	O
many	O
widely	O
used	O
applications	O
and	O
protocols	O
no	O
distinction	O
is	O
actually	O
made	O
between	O
the	O
presentation	O
and	O
application	B-Application
layers	I-Application
.	O
</s>
<s>
For	O
example	O
,	O
HyperText	B-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
HTTP	B-Protocol
)	O
,	O
generally	O
regarded	O
as	O
an	O
application-layer	B-Application
protocol	O
,	O
has	O
presentation-layer	B-Application
aspects	O
such	O
as	O
the	O
ability	O
to	O
identify	O
character	B-General_Concept
encoding	I-General_Concept
for	O
proper	O
conversion	O
,	O
which	O
is	O
then	O
done	O
in	O
the	O
application	B-Application
layer	I-Application
.	O
</s>
<s>
The	O
presentation	B-Application
layer	I-Application
is	O
the	O
lowest	O
layer	O
at	O
which	O
application	B-Application
programmers	O
consider	O
data	B-General_Concept
structure	I-General_Concept
and	O
presentation	O
,	O
instead	O
of	O
simply	O
sending	O
data	O
in	O
the	O
form	O
of	O
datagrams	B-Protocol
or	O
packets	B-Protocol
between	O
hosts	O
.	O
</s>
<s>
This	O
layer	O
deals	O
with	O
issues	O
of	O
string	O
representation	O
-	O
whether	O
they	O
use	O
the	O
Pascal	B-Application
method	O
(	O
an	O
integer	O
length	O
field	O
followed	O
by	O
the	O
specified	O
amount	O
of	O
bytes	O
)	O
or	O
the	O
C/C	O
++	O
method	O
(	O
null-terminated	O
strings	O
,	O
e.g.	O
</s>
<s>
The	O
idea	O
is	O
that	O
the	O
application	B-Application
layer	I-Application
should	O
be	O
able	O
to	O
point	O
at	O
the	O
data	O
to	O
be	O
moved	O
,	O
and	O
the	O
presentation	B-Application
layer	I-Application
will	O
translate	O
this	O
to	O
commands	O
able	O
to	O
be	O
understood	O
by	O
other	O
applications	O
and	O
processes	O
.	O
</s>
<s>
Serialization	B-Application
of	O
complex	O
data	B-General_Concept
structures	I-General_Concept
into	O
flat	O
byte-strings	O
(	O
using	O
mechanisms	O
such	O
as	O
TLV	B-Protocol
,	O
XML	B-Protocol
or	O
JSON	B-General_Concept
)	O
can	O
be	O
thought	O
of	O
as	O
the	O
key	O
functionality	O
of	O
the	O
presentation	B-Application
layer	I-Application
.	O
</s>
<s>
Structure	O
representation	O
is	O
normally	O
standardized	O
at	O
this	O
level	O
,	O
often	O
by	O
using	O
XML	B-Protocol
or	O
JSON	B-General_Concept
.	O
</s>
<s>
Two	O
common	O
examples	O
are	O
'	O
objects	O
 '	O
in	O
object-oriented	B-Language
programming	I-Language
,	O
and	O
the	O
exact	O
way	O
that	O
streaming	O
video	O
is	O
transmitted	O
.	O
</s>
<s>
Encryption	O
and	O
Decryption	O
are	O
typically	O
done	O
at	O
this	O
level	O
too	O
,	O
although	O
it	O
can	O
be	O
done	O
on	O
the	O
application	B-Application
,	O
session	B-Application
,	O
transport	B-Architecture
,	O
or	O
network	B-Application
layers	I-Application
,	O
each	O
having	O
its	O
own	O
advantages	O
and	O
disadvantages	O
.	O
</s>
<s>
For	O
example	O
,	O
when	O
logging	O
on	O
to	O
bank	O
account	O
sites	O
the	O
presentation	B-Application
layer	I-Application
will	O
decrypt	O
the	O
data	O
as	O
it	O
is	O
received	O
.	O
</s>
