<s>
Network	B-Protocol
Based	I-Protocol
Application	I-Protocol
Recognition	I-Protocol
(	O
NBAR	O
)	O
is	O
the	O
mechanism	O
used	O
by	O
some	O
Cisco	O
routers	B-Protocol
and	O
switches	B-Protocol
to	O
recognize	O
a	O
dataflow	O
by	O
inspecting	O
some	O
packets	B-Protocol
sent	O
.	O
</s>
<s>
The	O
networking	B-Architecture
equipment	O
which	O
uses	O
NBAR	O
does	O
a	O
deep	B-Application
packet	I-Application
inspection	I-Application
on	O
some	O
of	O
the	O
packets	B-Protocol
in	O
a	O
dataflow	O
,	O
to	O
determine	O
which	O
traffic	O
category	O
the	O
flow	O
belongs	O
to	O
.	O
</s>
<s>
The	O
categorization	O
may	O
be	O
done	O
with	O
Open	O
Systems	O
Interconnection	O
(	O
OSI	O
)	O
layer	O
4	O
info	O
,	O
packet	B-Protocol
content	O
,	O
signaling	O
,	O
and	O
so	O
on	O
but	O
some	O
new	O
applications	O
have	O
made	O
it	O
difficult	O
on	O
purpose	O
to	O
cling	O
to	O
this	O
kind	O
of	O
tagging	O
.	O
</s>
<s>
The	O
NBAR	O
approach	O
is	O
useful	O
in	O
dealing	O
with	O
malicious	O
software	O
using	O
known	O
ports	B-Protocol
to	O
fake	O
being	O
"	O
priority	O
traffic	O
"	O
,	O
as	O
well	O
as	O
non-standard	O
applications	O
using	O
dynamic	O
ports	B-Protocol
.	O
</s>
<s>
That	O
's	O
why	O
NBAR	O
is	O
also	O
known	O
as	O
OSI	B-Application
layer	I-Application
7	I-Application
categorization	O
.	O
</s>
<s>
On	O
Cisco	O
routers	B-Protocol
,	O
NBAR	O
is	O
mainly	O
used	O
for	O
quality	O
of	O
service	O
and	O
network	O
security	O
purposes	O
.	O
</s>
