<s>
ns	B-Language
(	O
from	O
network	O
simulator	O
)	O
is	O
a	O
name	O
for	O
a	O
series	O
of	O
discrete	B-General_Concept
event	I-General_Concept
network	O
simulators	O
,	O
specifically	O
ns-1	O
,	O
ns-2	O
,	O
and	O
ns-3	B-Language
.	O
</s>
<s>
The	O
first	O
version	O
of	O
ns	B-Language
,	O
known	O
as	O
ns-1	O
,	O
was	O
developed	O
at	O
Lawrence	O
Berkeley	O
National	O
Laboratory	O
(	O
LBNL	O
)	O
in	O
the	O
1995-97	O
timeframe	O
by	O
Steve	O
McCanne	O
,	O
Sally	O
Floyd	O
,	O
Kevin	O
Fall	O
,	O
and	O
other	O
contributors	O
.	O
</s>
<s>
Ns-2	O
began	O
as	O
a	O
revision	O
of	O
ns-1	O
.	O
</s>
<s>
From	O
1997	O
to	O
2000	O
,	O
ns	B-Language
development	O
was	O
supported	O
by	O
DARPA	O
through	O
the	O
VINT	O
project	O
at	O
LBL	O
,	O
Xerox	O
PARC	O
,	O
UCB	O
,	O
and	O
USC/ISI	O
.	O
</s>
<s>
In	O
2000	O
,	O
ns-2	O
development	O
was	O
supported	O
through	O
DARPA	O
with	O
SAMAN	O
and	O
through	O
NSF	O
with	O
CONSER	O
,	O
both	O
at	O
USC/ISI	O
,	O
in	O
collaboration	O
with	O
other	O
researchers	O
including	O
ACIRI	O
.	O
</s>
<s>
It	O
is	O
a	O
discrete	B-General_Concept
event	I-General_Concept
simulator	I-General_Concept
for	O
networking	O
research	O
.	O
</s>
<s>
Ns-2	O
incorporates	O
substantial	O
contributions	O
from	O
third	O
parties	O
,	O
including	O
wireless	O
code	O
from	O
the	O
UCB	O
Daedelus	O
and	O
CMU	O
Monarch	O
projects	O
and	O
Sun	O
Microsystems	O
.	O
</s>
<s>
In	O
2003	O
,	O
a	O
team	O
led	O
by	O
Tom	O
Henderson	O
,	O
George	O
Riley	O
,	O
Sally	O
Floyd	O
,	O
and	O
Sumit	O
Roy	O
,	O
applied	O
for	O
and	O
received	O
funding	O
from	O
the	O
U.S.	O
National	O
Science	O
Foundation	O
(	O
NSF	O
)	O
to	O
build	O
a	O
replacement	O
for	O
ns-2	O
,	O
called	O
ns-3	B-Language
.	O
</s>
<s>
In	O
the	O
process	O
of	O
developing	O
ns-3	B-Language
,	O
it	O
was	O
decided	O
to	O
completely	O
abandon	O
backward-compatibility	O
with	O
ns-2	O
.	O
</s>
<s>
The	O
new	O
simulator	O
would	O
be	O
written	O
from	O
scratch	O
,	O
using	O
the	O
C++	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
Development	O
of	O
ns-3	B-Language
began	O
in	O
July	O
2006	O
.	O
</s>
<s>
ns-1	O
development	O
stopped	O
when	O
ns-2	O
was	O
founded	O
.	O
</s>
<s>
ns-2	O
development	O
stopped	O
around	O
2010	O
.	O
</s>
<s>
ns-3	B-Language
is	O
actively	O
being	O
developed	O
and	O
maintained	O
.	O
</s>
<s>
ns-3	B-Language
is	O
built	O
using	O
C++	B-Language
and	O
Python	B-Language
with	O
scripting	O
capability	O
.	O
</s>
<s>
The	O
ns	B-Language
library	O
is	O
wrapped	O
by	O
Python	B-Language
thanks	O
to	O
the	O
pybindgen	O
library	O
which	O
delegates	O
the	O
parsing	O
of	O
the	O
ns	B-Language
C++	B-Language
headers	O
to	O
castxml	O
and	O
pygccxml	O
to	O
automatically	O
generate	O
the	O
corresponding	O
C++	B-Language
binding	O
glue	O
.	O
</s>
<s>
These	O
automatically	O
generated	O
C++	B-Language
files	O
are	O
finally	O
compiled	O
into	O
the	O
ns	B-Language
Python	B-Language
module	O
to	O
allow	O
users	O
to	O
interact	O
with	O
the	O
C++	B-Language
ns	B-Language
models	O
and	O
core	O
through	O
Python	B-Language
scripts	I-Language
.	O
</s>
<s>
The	O
ns	B-Language
simulator	O
features	O
an	O
integrated	O
attribute-based	O
system	O
to	O
manage	O
default	O
and	O
per-instance	O
values	O
for	O
simulation	O
parameters	O
.	O
</s>
<s>
To	O
build	O
ns	B-Language
you	O
need	O
a	O
computer	O
and	O
a	O
C++	B-Language
compiler	O
.	O
</s>
<s>
We	O
develop	O
ns	B-Language
on	O
several	O
kinds	O
of	O
Unix	O
(	O
FreeBSD	B-Operating_System
,	O
Linux	B-Application
,	O
SunOS	O
,	O
Solaris	O
)	O
,	O
so	O
it	O
installs	O
smoothest	O
there	O
,	O
but	O
it	O
should	O
run	O
on	O
an	O
Posix-like	O
computer	O
,	O
possibly	O
with	O
some	O
tweaking	O
.	O
</s>
<s>
Ns	B-Language
also	O
builds	O
and	O
runs	O
under	O
Windows	O
,	O
see	O
the	O
dedicated	O
Windows	O
/	O
Cygwin	O
page	O
.	O
</s>
<s>
Ns	B-Language
is	O
fairly	O
large	O
.	O
</s>
<s>
Building	O
ns	B-Language
from	O
pieces	O
can	O
save	O
some	O
disk	O
space	O
.	O
</s>
<s>
(	O
If	O
multiple	O
people	O
want	O
to	O
share	O
files	O
in	O
the	O
ns	B-Language
build	O
tree	O
to	O
save	O
space	O
,	O
you	O
may	O
download	O
a	O
simple	O
perl	O
script	O
,	O
then	O
follow	O
the	O
instruction	O
in	O
its	O
README	O
.	O
</s>
<s>
You	O
may	O
also	O
find	O
discussions	O
in	O
the	O
ns-users	O
mailing	O
list	O
archive	O
useful	O
.	O
)	O
</s>
<s>
As	O
of	O
November	O
2005	O
,	O
ns	B-Language
is	O
available	O
at	O
this	O
SourceForge	O
location	O
.	O
</s>
<s>
Ns	B-Language
requires	O
a	O
modestly	O
up-to-date	O
installation	O
of	O
Tcl/Tk	O
(	O
with	O
header	O
files	O
)	O
,	O
and	O
two	O
additional	O
packages	O
:	O
tclcl	O
and	O
otcl	O
.	O
</s>
<s>
There	O
are	O
two	O
typical	O
ways	O
to	O
build	O
ns	B-Language
:	O
building	O
each	O
component	O
individually	O
(	O
"	O
from	O
the	O
pieces	O
"	O
)	O
or	O
running	O
a	O
script	O
that	O
installs	O
them	O
all	O
in	O
one	O
shot	O
(	O
"	O
allinone	O
"	O
)	O
.	O
</s>
<s>
Installing	O
the	O
allinone	O
package	O
:	O
This	O
package	O
has	O
an	O
install	O
script	O
that	O
handles	O
installation	O
of	O
Tcl/Tk	O
,	O
OTcl	O
,	O
tclcl	O
,	O
ns-2	O
,	O
nam-1	O
and	O
other	O
packages	O
.	O
</s>
<s>
If	O
you	O
are	O
interested	O
in	O
the	O
convenience	O
of	O
the	O
allinone	O
package	O
for	O
your	O
platform	O
,	O
but	O
are	O
interested	O
in	O
using	O
a	O
fresher	O
snapshot	O
of	O
the	O
ns-2	O
code	O
,	O
this	O
page	O
is	O
for	O
you	O
.	O
</s>
<s>
Wouter	O
Horré	O
maintains	O
a	O
PPA	O
for	O
ns/nam	O
,	O
so	O
you	O
can	O
get	O
ready-to-use	O
deb	O
packages	O
there	O
.	O
</s>
<s>
Topology	O
definition	O
:	O
To	O
ease	O
the	O
creation	O
of	O
basic	O
facilities	O
and	O
define	O
their	O
interrelationships	O
,	O
ns-3	B-Language
has	O
a	O
system	O
of	O
containers	O
and	O
helpers	O
that	O
facilitates	O
this	O
process	O
.	O
</s>
<s>
This	O
data	O
can	O
then	O
be	O
statistically	O
analysed	O
with	O
tools	O
like	O
R	B-Language
to	O
draw	O
conclusions	O
.	O
</s>
<s>
Graphical	O
Visualization	O
:	O
Raw	O
or	O
processed	O
data	O
collected	O
in	O
a	O
simulation	O
can	O
be	O
graphed	O
using	O
tools	O
like	O
Gnuplot	B-Application
,	O
matplotlib	B-Language
or	O
XGRAPH	O
.	O
</s>
