<s>
In	O
computer	O
networking	O
,	O
MILNET	B-General_Concept
(	O
fully	O
Military	O
Network	O
)	O
was	O
the	O
name	O
given	O
to	O
the	O
part	O
of	O
the	O
ARPANET	O
internetwork	B-Architecture
designated	O
for	O
unclassified	O
United	O
States	O
Department	O
of	O
Defense	O
traffic	O
.	O
</s>
<s>
MILNET	B-General_Concept
was	O
physically	O
separated	O
from	O
the	O
ARPANET	O
in	O
1983	O
.	O
</s>
<s>
Gateways	B-Application
relayed	O
electronic	O
mail	O
between	O
the	O
two	O
networks	O
.	O
</s>
<s>
BBN	O
Technologies	O
built	O
and	O
managed	O
both	O
the	O
MILNET	B-General_Concept
and	O
the	O
ARPANET	O
and	O
the	O
two	O
networks	O
used	O
very	O
similar	O
technology	O
.	O
</s>
<s>
During	O
the	O
1980s	O
the	O
MILNET	B-General_Concept
expanded	O
as	O
part	O
of	O
the	O
Defense	O
Data	O
Network	O
,	O
a	O
worldwide	O
set	O
of	O
military	O
networks	O
running	O
at	O
different	O
security	O
levels	O
.	O
</s>
<s>
In	O
the	O
1990s	O
,	O
MILNET	B-General_Concept
became	O
the	O
NIPRNET	B-General_Concept
.	O
</s>
