<s>
A	O
stub	B-Architecture
network	I-Architecture
,	O
or	O
pocket	O
network	O
,	O
is	O
a	O
somewhat	O
casual	O
term	O
describing	O
a	O
computer	O
network	O
,	O
or	O
part	O
of	O
an	O
internetwork	B-Architecture
,	O
with	O
no	O
knowledge	O
of	O
other	O
networks	O
,	O
that	O
will	O
typically	O
send	O
much	O
or	O
all	O
of	O
its	O
non-local	O
traffic	O
out	O
via	O
a	O
single	O
path	O
,	O
with	O
the	O
network	O
aware	O
only	O
of	O
a	O
default	B-Protocol
route	I-Protocol
to	O
non-local	O
destinations	O
.	O
</s>
<s>
An	O
enterprise	O
that	O
connects	O
to	O
the	O
corporate	O
network	O
by	O
only	O
one	O
router	B-Protocol
,	O
or	O
multiple	O
default	B-Protocol
routers	I-Protocol
connected	O
to	O
the	O
same	O
logical	O
upstream	O
destination	O
.	O
</s>
<s>
A	O
single	O
LAN	B-General_Concept
which	O
never	O
carries	O
packets	B-Protocol
between	O
multiple	O
routers	B-Protocol
connected	O
to	O
it	O
.	O
</s>
<s>
All	O
traffic	O
is	O
to	O
and/or	O
from	O
local	O
hosts	B-Device
.	O
</s>
<s>
The	O
routers	B-Protocol
will	O
only	O
route	O
packets	B-Protocol
into	O
the	O
LAN	B-General_Concept
if	O
it	O
's	O
destined	O
for	O
the	O
LAN	B-General_Concept
,	O
and	O
out	O
from	O
the	O
LAN	B-General_Concept
if	O
it	O
originated	O
on	O
the	O
LAN	B-General_Concept
.	O
</s>
<s>
A	O
person	O
,	O
or	O
workgroup	O
,	O
who	O
is	O
connected	O
to	O
an	O
,	O
by	O
only	O
one	O
router	B-Protocol
,	O
is	O
a	O
stub	B-Architecture
network	I-Architecture
with	O
respect	O
to	O
the	O
ISP	O
.	O
</s>
<s>
This	O
stub	B-Architecture
network	I-Architecture
is	O
part	O
of	O
the	O
ISP	O
's	O
,	O
discussed	O
below	O
.	O
</s>
<s>
For	O
each	O
interface	B-Protocol
on	O
which	O
no	O
default	B-Protocol
route	I-Protocol
(	O
also	O
called	O
the	O
gateway	O
of	O
last	O
resort	O
)	O
has	O
been	O
elected	O
,	O
refers	O
to	O
these	O
subnets	B-Protocol
as	O
stub	B-Architecture
networks	I-Architecture
.	O
</s>
<s>
An	O
OSPF	B-Protocol
totally	O
stubby	O
area	O
is	O
one	O
which	O
only	O
has	O
a	O
default	B-Protocol
route	I-Protocol
to	O
the	O
rest	O
of	O
the	O
OSPF	B-Protocol
routing	B-Protocol
domain	I-Protocol
.	O
</s>
<s>
Such	O
an	O
area	O
may	O
have	O
more	O
than	O
one	O
router	B-Protocol
,	O
but	O
these	O
routers	B-Protocol
will	O
only	O
know	O
about	O
the	O
default	B-Protocol
route	I-Protocol
to	O
the	O
outside	O
.	O
</s>
<s>
A	O
stub	O
autonomous	B-Architecture
system	I-Architecture
that	O
is	O
connected	O
to	O
only	O
one	O
other	O
autonomous	B-Architecture
system	I-Architecture
,	O
through	O
which	O
it	O
gains	O
access	O
to	O
the	O
Internet	O
.	O
</s>
<s>
as	O
of	O
June	O
30	O
,	O
2007	O
,	O
there	O
were	O
224622	O
routes	O
seen	O
by	O
the	O
router	B-Protocol
.	O
</s>
<s>
These	O
came	O
from	O
25577	O
autonomous	B-Architecture
systems	I-Architecture
,	O
of	O
which	O
only	O
74	O
were	O
transit-only	O
and	O
22272	O
were	O
stub/origin	O
-only	O
.	O
</s>
<s>
3305	O
autonomous	B-Architecture
systems	I-Architecture
provided	O
some	O
level	O
of	O
transit	B-Application
.	O
</s>
<s>
Stub	B-Architecture
networks	I-Architecture
are	O
not	O
to	O
be	O
confused	O
with	O
transit	B-Application
networks	O
,	O
as	O
transit	B-Application
networks	O
contain	O
at	O
least	O
2	O
routers	B-Protocol
.	O
</s>
<s>
These	O
networks	O
differ	O
from	O
stub	B-Architecture
networks	I-Architecture
since	O
they	O
are	O
able	O
to	O
allow	O
information	O
to	O
pass	O
through	O
them	O
(	O
hence	O
the	O
name	O
)	O
.	O
</s>
<s>
The	O
stub	B-Architecture
network	I-Architecture
is	O
unique	O
in	O
the	O
sense	O
that	O
it	O
contains	O
only	O
one	O
router	B-Protocol
,	O
that	O
router	B-Protocol
being	O
the	O
gateway	O
to	O
the	O
network	O
.	O
</s>
<s>
Stub	B-Architecture
networks	I-Architecture
are	O
also	O
capable	O
of	O
implementing	O
multi-homing	B-Protocol
technology	O
.	O
</s>
<s>
This	O
technology	O
is	O
focused	O
on	O
setting	O
a	O
single	O
computer	O
to	O
host	O
multiple	O
network	O
connections	O
and	O
IP	B-Protocol
addresses	I-Protocol
.	O
</s>
<s>
Stub	B-Architecture
networks	I-Architecture
are	O
useful	O
in	O
situations	O
where	O
the	O
OSPF	B-Protocol
(	O
Open	B-Protocol
Shortest	I-Protocol
Path	I-Protocol
First	I-Protocol
)	O
protocol	O
needs	O
to	O
map	O
out	O
the	O
topology	B-Architecture
of	O
the	O
network	O
.	O
</s>
<s>
Stub	B-Architecture
networks	I-Architecture
serve	O
a	O
special	O
purpose	O
in	O
that	O
they	O
are	O
a	O
certain	O
area	O
within	O
the	O
construction	O
of	O
a	O
network	O
where	O
IP	B-Protocol
addresses	I-Protocol
are	O
filtered	O
out	O
and	O
replaced	O
with	O
default	B-Protocol
routes	I-Protocol
.	O
</s>
<s>
The	O
experimental	O
evaluation	O
of	O
stub	B-Architecture
networks	I-Architecture
has	O
pushed	O
for	O
the	O
use	O
of	O
ad	O
hoc	O
networks	O
to	O
act	O
as	O
stubs	O
for	O
larger	O
multi-service	O
networks	O
.	O
</s>
<s>
These	O
networks	O
are	O
connected	O
to	O
a	O
larger	O
infrastructure	O
in	O
order	O
to	O
deliver	O
a	O
range	O
of	O
services	O
including	O
security	O
,	O
deliverance	O
of	O
unicast	B-Protocol
and	O
multicast	O
services	O
,	O
and	O
many	O
others	O
to	O
improve	O
the	O
functionality	O
of	O
these	O
ad	O
hoc	O
networks	O
.	O
</s>
