<s>
A	O
network	B-Protocol
domain	I-Protocol
is	O
an	O
administrative	O
grouping	O
of	O
multiple	O
private	O
computer	B-Architecture
networks	I-Architecture
or	O
local	O
hosts	O
within	O
the	O
same	O
infrastructure	O
.	O
</s>
<s>
Domains	O
can	O
be	O
identified	O
using	O
a	O
domain	O
name	O
;	O
domains	O
which	O
need	O
to	O
be	O
accessible	O
from	O
the	O
public	O
Internet	O
can	O
be	O
assigned	O
a	O
globally	O
unique	O
name	O
within	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
(	O
DNS	B-Protocol
)	O
.	O
</s>
<s>
A	O
domain	B-Protocol
controller	I-Protocol
is	O
a	O
server	O
that	O
automates	O
the	O
logins	O
,	O
user	O
groups	O
,	O
and	O
architecture	O
of	O
a	O
domain	O
,	O
rather	O
than	O
manually	O
coding	B-Error_Name
this	O
information	O
on	O
each	O
host	O
in	O
the	O
domain	O
.	O
</s>
<s>
It	O
is	O
common	O
practice	O
,	O
but	O
not	O
required	O
,	O
to	O
have	O
the	O
domain	B-Protocol
controller	I-Protocol
act	O
as	O
a	O
DNS	B-Protocol
server	O
.	O
</s>
<s>
That	O
is	O
,	O
it	O
would	O
assign	O
names	O
to	O
hosts	O
in	O
the	O
network	O
based	O
on	O
their	O
IP	B-Protocol
addresses	I-Protocol
.	O
</s>
<s>
This	O
network	O
has	O
the	O
VLAN	B-General_Concept
identifier	O
of	O
VLAN	B-General_Concept
10	O
.	O
</s>
<s>
This	O
network	O
has	O
the	O
VLAN	B-General_Concept
identifier	O
of	O
VLAN	B-General_Concept
20	O
.	O
</s>
<s>
This	O
has	O
the	O
VLAN	B-General_Concept
identifier	O
of	O
VLAN	B-General_Concept
11	O
.	O
</s>
<s>
Network	O
2	O
and	O
3	O
are	O
therefore	O
in	O
the	O
same	O
network	B-Protocol
domain	I-Protocol
,	O
while	O
Network	O
1	O
is	O
in	O
its	O
own	O
network	B-Protocol
domain	I-Protocol
,	O
albeit	O
alone	O
.	O
</s>
<s>
A	O
network	O
administrator	O
can	O
then	O
suitably	O
name	O
these	O
network	B-Protocol
domains	I-Protocol
to	O
match	O
the	O
infrastructure	O
topology	B-Architecture
.	O
</s>
<s>
Use	O
of	O
the	O
term	O
"	O
network	B-Protocol
domain	I-Protocol
"	O
first	O
appeared	O
in	O
1965	O
and	O
saw	O
increasing	O
usage	O
beginning	O
in	O
1985	O
.	O
</s>
<s>
It	O
initially	O
applied	O
to	O
the	O
naming	O
of	O
radio	O
stations	O
based	O
on	O
broadcast	B-Algorithm
frequency	I-Algorithm
and	O
geographic	O
area	O
.	O
</s>
<s>
It	O
entered	O
its	O
current	O
usage	O
by	O
network	O
theorists	O
to	O
describe	O
solutions	O
to	O
the	O
problems	O
of	O
subdividing	O
a	O
single	O
homogeneous	O
LAN	O
and	O
joining	O
multiple	O
networks	O
,	O
possibly	O
constituted	O
of	O
different	O
network	B-Architecture
architectures	I-Architecture
.	O
</s>
