<s>
In	O
digital	O
communications	O
networks	O
,	O
packet	B-Protocol
processing	I-Protocol
refers	O
to	O
the	O
wide	O
variety	O
of	O
algorithms	O
that	O
are	O
applied	O
to	O
a	O
packet	B-Protocol
of	O
data	O
or	O
information	O
as	O
it	O
moves	O
through	O
the	O
various	O
network	O
elements	O
of	O
a	O
communications	O
network	O
.	O
</s>
<s>
With	O
the	O
increased	O
performance	O
of	O
network	O
interfaces	O
,	O
there	O
is	O
a	O
corresponding	O
need	O
for	O
faster	O
packet	B-Protocol
processing	I-Protocol
.	O
</s>
<s>
There	O
are	O
two	O
broad	O
classes	O
of	O
packet	B-Protocol
processing	I-Protocol
algorithms	O
that	O
align	O
with	O
the	O
standardized	O
network	O
subdivision	O
of	O
control	B-Protocol
plane	I-Protocol
and	O
data	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
The	O
data	O
content	O
(	O
frequently	O
called	O
the	O
payload	O
)	O
of	O
the	O
packet	B-Protocol
which	O
is	O
used	O
to	O
provide	O
some	O
content-specific	O
transformation	O
or	O
take	O
a	O
content-driven	O
action	O
.	O
</s>
<s>
router	B-Protocol
,	O
switch	O
,	O
network	O
element	O
or	O
terminal	O
such	O
as	O
a	O
computer	O
or	O
smartphone	O
)	O
it	O
is	O
the	O
packet	B-Protocol
processing	I-Protocol
subsystem	O
that	O
manages	O
the	O
traversal	O
of	O
the	O
multi-layered	O
network	O
or	O
protocol	B-Protocol
stack	I-Protocol
from	O
the	O
lower	O
,	O
physical	B-Application
and	O
network	B-Application
layers	I-Application
all	O
the	O
way	O
through	O
to	O
the	O
application	B-Application
layer	I-Application
.	O
</s>
<s>
The	O
history	O
of	O
packet	B-Protocol
processing	I-Protocol
is	O
the	O
history	O
of	O
the	O
Internet	O
and	O
packet	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
Packet	B-Protocol
processing	I-Protocol
milestones	O
include	O
:	O
</s>
<s>
1973	O
:	O
Packet	B-Protocol
switched	I-Protocol
voice	O
connections	O
over	O
ARPANET	O
with	O
Network	B-Protocol
Voice	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
The	O
OSI	O
Model	O
is	O
a	O
7	O
layer	O
model	O
describing	O
how	O
a	O
network	O
operating	B-General_Concept
system	I-General_Concept
works	O
.	O
</s>
<s>
The	O
internetworking	O
protocol	O
developed	O
to	O
support	O
the	O
network	O
,	O
called	O
ARPAnet	O
,	O
was	O
called	O
TCP	B-Protocol
or	O
Transmission	B-Protocol
Control	I-Protocol
Program	I-Protocol
.	O
</s>
<s>
This	O
led	O
to	O
the	O
splitting	O
of	O
the	O
original	O
TCP	B-Protocol
and	O
the	O
creation	O
of	O
the	O
TCP/IP	B-Protocol
architecture	O
-	O
TCP	B-Protocol
now	O
standing	O
for	O
Transmission	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
and	O
IP	B-Protocol
standing	O
for	O
Internet	B-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
Packet	B-Protocol
networks	I-Protocol
came	O
about	O
as	O
a	O
result	O
of	O
the	O
need	O
in	O
the	O
early	O
1960s	O
to	O
make	O
communications	O
networks	O
more	O
reliable	O
.	O
</s>
<s>
It	O
can	O
be	O
viewed	O
as	O
the	O
implementation	O
of	O
the	O
layered	O
model	O
using	O
a	O
packet	B-Protocol
structure	O
.	O
</s>
<s>
The	O
concept	O
of	O
packet	B-Protocol
switching	I-Protocol
was	O
introduced	O
to	O
create	O
a	O
communications	O
network	O
that	O
would	O
continue	O
to	O
function	O
in	O
spite	O
of	O
equipment	O
failures	O
throughout	O
the	O
network	O
.	O
</s>
<s>
In	O
this	O
paradigm	O
shift	O
,	O
networks	O
are	O
viewed	O
as	O
collections	O
of	O
systems	O
that	O
transmit	O
data	O
in	O
small	O
packets	B-Protocol
that	O
work	O
their	O
way	O
from	O
origin	O
to	O
destination	O
by	O
any	O
number	O
of	O
routes	O
.	O
</s>
<s>
Initial	O
packet	B-Protocol
processing	I-Protocol
functions	O
supported	O
the	O
routing	B-Protocol
of	O
packets	B-Protocol
through	O
the	O
network	O
,	O
transmission	B-Error_Name
error	I-Error_Name
detection	I-Error_Name
and	I-Error_Name
correction	I-Error_Name
and	O
other	O
network	O
management	O
functions	O
.	O
</s>
<s>
Packet	B-Protocol
switching	I-Protocol
with	O
its	O
supporting	O
packet	B-Protocol
processing	I-Protocol
functions	O
has	O
several	O
practical	O
benefits	O
over	O
traditional	O
circuit-switched	O
networks	O
:	O
</s>
<s>
A	O
network	B-Protocol
packet	I-Protocol
is	O
the	O
fundamental	O
building	O
block	O
for	O
packet-switched	B-Protocol
networks	I-Protocol
.	O
</s>
<s>
When	O
an	O
item	O
such	O
as	O
a	O
file	O
,	O
e-mail	O
message	O
,	O
voice	O
or	O
video	O
stream	O
is	O
transmitted	O
through	O
the	O
network	O
,	O
it	O
is	O
broken	O
into	O
chunks	O
called	O
packets	B-Protocol
that	O
can	O
be	O
more	O
efficiently	O
moved	O
through	O
the	O
network	O
than	O
one	O
large	O
block	O
of	O
data	O
.	O
</s>
<s>
Numerous	O
standards	O
cover	O
the	O
structure	O
of	O
packets	B-Protocol
,	O
but	O
typically	O
packets	B-Protocol
are	O
composed	O
of	O
three	O
elements	O
:	O
</s>
<s>
Header	B-General_Concept
–	O
contains	O
information	O
about	O
the	O
packet	B-Protocol
,	O
including	O
origin	O
,	O
destination	O
,	O
length	O
and	O
packet	B-Protocol
number	O
.	O
</s>
<s>
In	O
a	O
packet-switched	B-Protocol
network	I-Protocol
,	O
the	O
sending	O
host	O
computer	O
packetizes	O
the	O
original	O
item	O
and	O
each	O
packet	B-Protocol
is	O
routed	B-Protocol
through	O
the	O
network	O
to	O
its	O
destination	O
.	O
</s>
<s>
Some	O
networks	O
used	O
fixed	O
length	O
packets	B-Protocol
,	O
typically	O
1024	O
bits	O
,	O
while	O
others	O
use	O
variable	O
length	O
packets	B-Protocol
and	O
include	O
the	O
packet	B-Protocol
length	O
in	O
the	O
header	B-General_Concept
.	O
</s>
<s>
Individual	O
packets	B-Protocol
may	O
take	O
different	O
routes	O
to	O
the	O
destination	O
and	O
arrive	O
at	O
the	O
destination	O
out	O
of	O
order	O
.	O
</s>
<s>
The	O
destination	O
computer	O
verifies	O
the	O
correctness	O
of	O
the	O
data	O
in	O
each	O
packet	B-Protocol
(	O
using	O
information	O
in	O
the	O
trailer	B-Device
)	O
,	O
reassembles	O
the	O
original	O
item	O
using	O
the	O
packet	B-Protocol
number	O
information	O
in	O
the	O
header	B-General_Concept
,	O
and	O
presents	O
the	O
item	O
to	O
the	O
receiving	O
application	O
or	O
user	O
.	O
</s>
<s>
This	O
basic	O
example	O
includes	O
the	O
three	O
most	O
fundamental	O
packet	B-Protocol
processing	I-Protocol
functions	O
,	O
packetization	O
,	O
routing	B-Protocol
,	O
and	O
assembly	O
.	O
</s>
<s>
Packet	B-Protocol
processing	I-Protocol
functions	O
range	O
from	O
the	O
simple	O
to	O
highly	O
complex	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
the	O
routing	B-Protocol
function	O
is	O
actually	O
a	O
multi-step	O
process	O
involving	O
various	O
optimization	O
algorithms	O
and	O
table	O
lookups	O
.	O
</s>
<s>
A	O
basic	O
routing	B-Protocol
function	O
on	O
the	O
Internet	O
looks	O
something	O
like	O
:	O
</s>
<s>
If	O
so	O
,	O
process	O
the	O
packet	B-Protocol
.	O
</s>
<s>
Check	O
to	O
see	O
if	O
IP	B-Protocol
Forwarding	I-Protocol
is	O
set	O
to	O
‘	O
Yes’	O
.	O
</s>
<s>
If	O
no	O
,	O
the	O
packet	B-Protocol
is	O
destroyed	O
.	O
</s>
<s>
If	O
yes	O
,	O
route	O
the	O
packet	B-Protocol
to	O
the	O
appropriate	O
network	O
.	O
</s>
<s>
If	O
yes	O
,	O
route	O
the	O
packet	B-Protocol
to	O
the	O
next	O
hop	O
gateway	O
.	O
</s>
<s>
If	O
no	O
,	O
destroy	O
the	O
packet	B-Protocol
.	O
</s>
<s>
More	O
advanced	O
routing	B-Protocol
functions	O
include	O
network	O
load	B-Application
balancing	I-Application
and	O
fastest	O
route	O
algorithms	O
.	O
</s>
<s>
These	O
examples	O
illustrate	O
the	O
range	O
of	O
packet	B-Protocol
processing	I-Protocol
algorithms	O
possible	O
and	O
how	O
they	O
can	O
introduce	O
significant	O
delays	O
into	O
the	O
transmission	O
of	O
an	O
item	O
.	O
</s>
<s>
IP-based	O
equipment	O
can	O
be	O
partitioned	O
into	O
three	O
basic	O
elements	O
:	O
data	B-Protocol
plane	I-Protocol
,	O
control	B-Protocol
plane	I-Protocol
and	O
management	O
plane	O
.	O
</s>
<s>
The	O
data	B-Protocol
plane	I-Protocol
is	O
a	O
subsystem	O
of	O
a	O
network	O
node	O
that	O
receives	O
and	O
sends	O
packets	B-Protocol
from	O
an	O
interface	O
,	O
processes	O
them	O
as	O
required	O
by	O
the	O
applicable	O
protocol	O
,	O
and	O
delivers	O
,	O
drops	O
,	O
or	O
forwards	O
them	O
as	O
appropriate	O
.	O
</s>
<s>
The	O
control	B-Protocol
plane	I-Protocol
maintains	O
information	O
that	O
can	O
be	O
used	O
to	O
change	O
data	O
used	O
by	O
the	O
data	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
Implementing	O
these	O
protocols	O
in	O
the	O
data	B-Protocol
plane	I-Protocol
would	O
lead	O
to	O
poor	O
forwarding	B-Protocol
performance	O
.	O
</s>
<s>
A	O
common	O
way	O
to	O
manage	O
these	O
protocols	O
is	O
to	O
let	O
the	O
data	B-Protocol
plane	I-Protocol
detect	O
incoming	O
signaling	O
packets	B-Protocol
and	O
locally	O
forward	O
them	O
to	O
the	O
control	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
The	O
control	B-Protocol
plane	I-Protocol
signaling	O
protocols	O
can	O
update	O
the	O
data	B-Protocol
plane	I-Protocol
information	O
and	O
inject	O
outgoing	O
signaling	O
packets	B-Protocol
into	O
the	O
data	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
Command	O
line	O
interface	O
,	O
graphical	O
user	O
configuration	O
interfaces	O
through	O
Web	O
pages	O
or	O
traditional	O
SNMP	B-Protocol
(	O
Simple	B-Protocol
Network	I-Protocol
Management	I-Protocol
Protocol	I-Protocol
)	O
management	O
.	O
</s>
<s>
More	O
sophisticated	O
solutions	O
based	O
on	O
XML	B-Protocol
(	O
eXtensible	B-Protocol
Markup	I-Protocol
Language	I-Protocol
)	O
can	O
also	O
be	O
included	O
.	O
</s>
<s>
The	O
list	O
of	O
packet	B-Protocol
processing	I-Protocol
applications	O
is	O
usually	O
divided	O
into	O
two	O
categories	O
.	O
</s>
<s>
Advanced	O
applications	O
include	O
areas	O
such	O
as	O
security	O
(	O
call	O
monitoring	O
and	O
data	B-Application
leak	I-Application
prevention	I-Application
)	O
,	O
targeted	O
advertising	O
,	O
tiered	O
services	O
,	O
copyright	O
enforcement	O
and	O
network	O
usage	O
statistics	O
.	O
</s>
<s>
These	O
,	O
and	O
many	O
other	O
content-aware	O
applications	O
,	O
are	O
based	O
on	O
the	O
ability	O
to	O
discern	O
specific	O
intelligence	O
contained	O
within	O
packet	B-Protocol
payloads	O
using	O
Deep	B-Application
Packet	I-Application
Inspection	I-Application
(	O
DPI	O
)	O
technologies	O
.	O
</s>
<s>
Packet	B-Protocol
switching	I-Protocol
also	O
introduces	O
some	O
architectural	O
compromises	O
.	O
</s>
<s>
Performing	O
packet	B-Protocol
processing	I-Protocol
functions	O
in	O
the	O
transmission	O
of	O
information	O
introduces	O
delays	O
that	O
may	O
be	O
detrimental	O
to	O
the	O
application	O
being	O
performed	O
.	O
</s>
<s>
Multiple	O
architectural	O
approaches	O
to	O
packet	B-Protocol
processing	I-Protocol
have	O
been	O
developed	O
to	O
address	O
the	O
performance	O
and	O
functionality	O
requirements	O
of	O
a	O
specific	O
network	O
and	O
to	O
address	O
the	O
latency	O
issue	O
.	O
</s>
<s>
A	O
standard	B-Protocol
networking	I-Protocol
stack	I-Protocol
uses	O
services	O
provided	O
by	O
the	O
Operating	B-General_Concept
System	I-General_Concept
(	O
OS	O
)	O
running	O
on	O
a	O
single	O
processor	O
(	O
single	B-Operating_System
threaded	I-Operating_System
)	O
.	O
</s>
<s>
While	O
single	B-Operating_System
threaded	I-Operating_System
architectures	O
are	O
the	O
simplest	O
to	O
implement	O
,	O
they	O
are	O
subject	O
to	O
overheads	O
associated	O
with	O
the	O
performance	O
of	O
OS	O
functions	O
such	O
as	O
preemptions	O
,	O
thread	B-Operating_System
management	I-Operating_System
,	O
timers	O
and	O
locking	O
.	O
</s>
<s>
These	O
OS	O
processing	O
overheads	O
are	O
imposed	O
on	O
each	O
packet	B-Protocol
passing	O
through	O
the	O
system	O
,	O
resulting	O
in	O
a	O
throughput	O
penalty	O
.	O
</s>
<s>
Performance	O
improvements	O
can	O
be	O
made	O
to	O
an	O
OS	O
networking	B-Protocol
stack	I-Protocol
by	O
adapting	O
the	O
protocol	B-Protocol
stack	I-Protocol
processing	O
software	O
to	O
support	O
multiple	O
processors	O
(	O
multi-threaded	B-Operating_System
)	O
,	O
either	O
through	O
the	O
use	O
of	O
Symmetrical	B-Operating_System
Multiprocessing	I-Operating_System
(	O
SMP	O
)	O
platforms	O
or	O
multicore	B-Architecture
processor	I-Architecture
architecture	I-Architecture
.	O
</s>
<s>
Performance	O
increases	O
are	O
realized	O
for	O
a	O
small	O
number	O
of	O
processors	O
,	O
but	O
fails	O
to	O
scale	O
linearly	O
over	O
larger	O
numbers	O
of	O
processors	O
(	O
or	O
cores	O
)	O
and	O
a	O
processor	O
with	O
,	O
for	O
example	O
,	O
eight	O
cores	O
may	O
not	O
process	O
packets	B-Protocol
significantly	O
faster	O
than	O
one	O
with	O
two	O
cores	O
.	O
</s>
<s>
In	O
a	O
fast	B-General_Concept
path	I-General_Concept
implementation	O
,	O
the	O
data	B-Protocol
plane	I-Protocol
is	O
split	O
into	O
two	O
layers	O
.	O
</s>
<s>
The	O
lower	O
layer	O
,	O
typically	O
called	O
the	O
fast	B-General_Concept
path	I-General_Concept
,	O
processes	O
the	O
majority	O
of	O
incoming	O
packets	B-Protocol
outside	O
the	O
OS	O
environment	O
and	O
without	O
incurring	O
any	O
of	O
the	O
OS	O
overheads	O
that	O
degrade	O
overall	O
performance	O
.	O
</s>
<s>
Only	O
those	O
packets	B-Protocol
that	O
require	O
complex	O
processing	O
are	O
forwarded	O
to	O
the	O
OS	O
networking	B-Protocol
stack	I-Protocol
(	O
the	O
upper	O
layer	O
of	O
the	O
data	B-Protocol
plane	I-Protocol
)	O
,	O
which	O
performs	O
the	O
necessary	O
management	O
,	O
signaling	O
and	O
control	O
functions	O
.	O
</s>
<s>
When	O
complex	O
algorithms	O
such	O
as	O
routing	B-Protocol
or	O
security	O
are	O
required	O
,	O
the	O
OS	O
networking	B-Protocol
stack	I-Protocol
forwards	O
the	O
packet	B-Protocol
to	O
dedicated	O
software	O
components	O
in	O
the	O
control	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
A	O
multicore	B-Architecture
processor	I-Architecture
can	O
provide	O
additional	O
performance	O
improvement	O
to	O
a	O
fast	B-General_Concept
path	I-General_Concept
implementation	O
.	O
</s>
<s>
In	O
order	O
to	O
maximize	O
the	O
overall	O
system	O
throughput	O
,	O
multiple	O
cores	O
can	O
be	O
dedicated	O
to	O
running	O
the	O
fast	B-General_Concept
path	I-General_Concept
,	O
while	O
only	O
one	O
core	O
is	O
required	O
to	O
run	O
the	O
Operating	B-General_Concept
System	I-General_Concept
,	O
the	O
OS	O
networking	B-Protocol
stack	I-Protocol
and	O
the	O
application	O
’s	O
control	B-Protocol
plane	I-Protocol
.	O
</s>
<s>
The	O
only	O
restriction	O
when	O
configuring	O
the	O
platform	O
is	O
that	O
,	O
since	O
the	O
cores	O
running	O
the	O
fast	B-General_Concept
path	I-General_Concept
are	O
running	O
outside	O
the	O
OS	O
,	O
they	O
must	O
be	O
dedicated	O
exclusively	O
to	O
the	O
fast	B-General_Concept
path	I-General_Concept
and	O
not	O
shared	O
with	O
other	O
software	O
.	O
</s>
<s>
Splitting	O
the	O
data	B-Protocol
plane	I-Protocol
into	O
two	O
layers	O
also	O
adds	O
complexity	O
as	O
the	O
two	O
layers	O
must	O
have	O
the	O
same	O
information	O
to	O
ensure	O
system	O
consistency	O
.	O
</s>
<s>
In	O
order	O
to	O
create	O
specialized	O
packet	B-Protocol
processing	I-Protocol
platforms	O
,	O
a	O
variety	O
of	O
technologies	O
have	O
been	O
developed	O
and	O
deployed	O
.	O
</s>
<s>
A	O
network	B-General_Concept
processor	I-General_Concept
unit	O
(	O
NPU	O
)	O
is	O
similar	O
in	O
many	O
respects	O
to	O
general	O
purpose	O
processors	O
(	O
GPP	O
)	O
that	O
power	O
most	O
computers	O
but	O
with	O
its	O
internal	O
architecture	O
and	O
functions	O
tailored	O
to	O
network-centric	O
operations	O
.	O
</s>
<s>
NPUs	O
commonly	O
have	O
network-specific	O
functions	O
such	O
as	O
address	O
lookup	O
,	O
pattern	B-Language
matching	I-Language
and	O
queue	B-Application
management	O
built	O
into	O
their	O
microcode	B-Device
.	O
</s>
<s>
Higher	O
level	O
packet	B-Protocol
processing	I-Protocol
operations	O
such	O
as	O
security	O
or	O
intrusion	O
detection	O
are	O
often	O
built	O
into	O
NPU	O
architectures	O
.	O
</s>
<s>
Network	B-General_Concept
processor	I-General_Concept
examples	O
would	O
include	O
:	O
</s>
<s>
A	O
multicore	B-Architecture
processor	I-Architecture
is	O
a	O
single	O
semiconductor	O
package	O
that	O
has	O
2	O
or	O
more	O
cores	O
,	O
each	O
representing	O
an	O
individual	O
processing	O
unit	O
,	O
capable	O
of	O
executing	O
code	O
in	O
parallel	O
.	O
</s>
<s>
General	O
purpose	O
CPUs	B-Device
such	O
as	O
the	O
Intel	B-Device
Xeon	I-Device
now	O
support	O
up	O
to	O
8	O
cores	O
.	O
</s>
<s>
Some	O
multicore	B-Architecture
processors	I-Architecture
integrate	O
dedicated	O
packet	B-Protocol
processing	I-Protocol
capabilities	O
to	O
provide	O
a	O
complete	O
SoC	O
(	O
System	O
on	O
Chip	O
)	O
.	O
</s>
<s>
They	O
generally	O
integrate	O
Ethernet	O
interfaces	O
,	O
crypto-engines	O
,	O
pattern	B-Language
matching	I-Language
engines	O
,	O
hardware	O
queues	B-Application
for	O
QoS	O
and	O
sometimes	O
more	O
sophisticated	O
functions	O
using	O
micro-cores	O
.	O
</s>
<s>
All	O
these	O
hardware	O
features	O
are	O
able	O
to	O
offload	O
the	O
software	O
packet	B-Protocol
processing	I-Protocol
.	O
</s>
<s>
Recent	O
examples	O
of	O
these	O
specialized	O
multicore	B-Architecture
packages	O
,	O
such	O
as	O
the	O
Cavium	O
OCTEON	O
II	O
,	O
can	O
support	O
from	O
2	O
up	O
to	O
32	O
cores	O
.	O
</s>
<s>
Initial	O
implementations	O
used	O
FPGAs	B-Architecture
(	O
field-programmable	B-Architecture
gate	I-Architecture
array	I-Architecture
)	O
or	O
ASICs	O
(	O
Application-specific	O
Integrated	O
Circuit	O
)	O
,	O
but	O
now	O
specific	O
functions	O
such	O
as	O
encryption	O
and	O
compression	O
are	O
built	O
into	O
both	O
GPPs	O
and	O
NPUs	O
as	O
internal	O
hardware	O
accelerators	O
.	O
</s>
<s>
Current	O
multicore	B-Architecture
processor	I-Architecture
examples	O
with	O
network-specific	O
hardware	O
accelerators	O
include	O
the	O
Cavium	O
CN63xx	O
with	O
acceleration	O
for	O
security	O
,	O
TCP/IP	B-Protocol
,	O
QOS	O
and	O
HFA	O
pattern	B-Language
matching	I-Language
and	O
the	O
Netlogic	O
Microsystems	O
XFS	O
processor	O
family	O
with	O
networking	O
and	O
security	O
acceleration	O
engines	O
.	O
</s>
<s>
Being	O
able	O
to	O
make	O
decisions	O
based	O
on	O
the	O
content	O
of	O
individual	O
packets	B-Protocol
enables	O
a	O
wide	O
variety	O
of	O
new	O
applications	O
such	O
as	O
Policy	B-Protocol
Charging	I-Protocol
and	I-Protocol
Rules	I-Protocol
Functions	I-Protocol
(	O
PCRF	B-Protocol
)	O
and	O
Quality	O
of	O
Service	O
.	O
</s>
<s>
Packet	B-Protocol
processing	I-Protocol
systems	O
separate	O
out	O
specific	O
traffic	O
types	O
through	O
the	O
use	O
of	O
Deep	B-Application
Packet	I-Application
Inspection	I-Application
(	O
DPI	O
)	O
technologies	O
.	O
</s>
<s>
DPI	O
technologies	O
utilize	O
pattern	B-Language
matching	I-Language
algorithms	O
to	O
look	O
inside	O
the	O
data	O
payload	O
to	O
identify	O
the	O
contents	O
of	O
each	O
and	O
every	O
packet	B-Protocol
flowing	O
through	O
a	O
network	O
device	O
.	O
</s>
<s>
Successful	O
pattern	B-Language
matches	I-Language
are	O
reported	O
to	O
the	O
controlling	O
application	O
for	O
any	O
appropriate	O
further	O
action	O
to	O
be	O
taken	O
.	O
</s>
<s>
Operating	B-General_Concept
system	I-General_Concept
software	O
will	O
contain	O
certain	O
standard	O
network	B-Protocol
stacks	I-Protocol
that	O
will	O
operate	O
in	O
both	O
single	O
and	O
multicore	B-Architecture
environments	O
.	O
</s>
<s>
To	O
be	O
able	O
to	O
implement	O
operating	B-General_Concept
system	I-General_Concept
by-pass	O
(	O
fast	B-General_Concept
path	I-General_Concept
)	O
architectures	O
requires	O
the	O
use	O
of	O
specialized	O
packet	B-Protocol
processing	I-Protocol
software	O
such	O
as	O
6WIND	O
's	O
6WINDGate	O
.	O
</s>
