<s>
A	O
residential	B-Application
gateway	I-Application
is	O
a	O
small	O
consumer-grade	O
gateway	O
which	O
bridges	B-Protocol
network	O
access	O
between	O
connected	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
(	O
LAN	B-General_Concept
)	O
hosts	O
to	O
a	O
wide	O
area	O
network	O
(	O
WAN	O
)	O
(	O
such	O
as	O
the	O
Internet	O
)	O
via	O
a	O
modem	B-Application
,	O
or	O
directly	O
connects	O
to	O
a	O
WAN	O
(	O
as	O
in	O
EttH	B-Protocol
)	O
,	O
while	O
routing	B-Protocol
.	O
</s>
<s>
The	O
WAN	O
is	O
a	O
larger	O
computer	B-Architecture
network	I-Architecture
,	O
generally	O
operated	O
by	O
an	O
Internet	O
service	O
provider	O
.	O
</s>
<s>
Multiple	O
devices	O
have	O
been	O
described	O
as	O
residential	B-Application
gateways	I-Application
:	O
</s>
<s>
A	O
modem	B-Application
(	O
e.g.	O
</s>
<s>
DSL	B-Device
modem	I-Device
,	O
Cable	B-Device
modem	I-Device
)	O
by	O
itself	O
provides	O
none	O
of	O
the	O
functions	O
of	O
a	O
router	B-Protocol
.	O
</s>
<s>
It	O
merely	O
allows	O
ATM	O
or	O
PPP	B-Protocol
or	O
PPPoE	B-Protocol
traffic	O
to	O
be	O
transmitted	O
across	O
telephone	O
lines	O
,	O
cable	O
wires	O
,	O
optical	O
fibers	O
,	O
wireless	O
radio	O
frequencies	O
,	O
or	O
other	O
physical	O
layers	O
.	O
</s>
<s>
On	O
the	O
receiving	O
end	O
is	O
another	O
modem	B-Application
that	O
re-converts	O
the	O
transmission	O
format	O
back	O
into	O
digital	O
data	O
packets	O
.	O
</s>
<s>
This	O
allows	O
network	B-Protocol
bridging	I-Protocol
using	O
telephone	O
,	O
cable	O
,	O
optical	O
,	O
and	O
radio	O
connection	O
methods	O
.	O
</s>
<s>
The	O
modem	B-Application
also	O
provides	O
handshake	B-Protocol
protocols	I-Protocol
,	O
so	O
that	O
the	O
devices	O
on	O
each	O
end	O
of	O
the	O
connection	O
are	O
able	O
to	O
recognize	O
each	O
other	O
.	O
</s>
<s>
However	O
,	O
a	O
modem	B-Application
generally	O
provides	O
few	O
other	O
network	O
functions	O
.	O
</s>
<s>
A	O
USB	B-Protocol
modem	B-Application
plugs	O
into	O
a	O
single	O
PC	O
and	O
allows	O
a	O
connection	O
of	O
that	O
single	O
PC	O
to	O
a	O
WAN	O
.	O
</s>
<s>
If	O
properly	O
configured	O
,	O
the	O
PC	O
can	O
also	O
function	O
as	O
the	O
router	B-Protocol
for	O
a	O
home	O
LAN	B-General_Concept
.	O
</s>
<s>
An	O
internal	B-Application
modem	I-Application
can	O
be	O
installed	O
on	O
a	O
single	O
PC	O
(	O
e.g.	O
</s>
<s>
on	O
a	O
PCI	B-Protocol
card	I-Protocol
)	O
,	O
also	O
allowing	O
that	O
single	O
PC	O
to	O
connect	O
to	O
a	O
WAN	O
.	O
</s>
<s>
Again	O
,	O
the	O
PC	O
can	O
be	O
configured	O
to	O
function	O
as	O
a	O
router	B-Protocol
for	O
a	O
home	O
LAN	B-General_Concept
.	O
</s>
<s>
A	O
cellular	O
wireless	B-Device
access	I-Device
point	I-Device
can	O
function	O
in	O
a	O
similar	O
fashion	O
to	O
a	O
modem	B-Application
.	O
</s>
<s>
It	O
can	O
allow	O
a	O
direct	O
connection	O
from	O
a	O
home	O
LAN	B-General_Concept
to	O
a	O
WWAN	B-General_Concept
,	O
if	O
a	O
wireless	B-Device
router	I-Device
or	O
access	O
point	O
is	O
present	O
on	O
the	O
WAN	O
as	O
well	O
and	O
tethering	O
is	O
allowed	O
.	O
</s>
<s>
Many	O
modems	B-Application
now	O
incorporate	O
the	O
features	O
mentioned	O
below	O
and	O
thus	O
are	O
appropriately	O
described	O
as	O
residential	B-Application
gateways	I-Application
,	O
such	O
as	O
some	O
Internet	O
providers	O
which	O
offer	O
a	O
cable	B-Device
modem	I-Device
router	B-Protocol
combo	O
.	O
</s>
<s>
routing	B-Protocol
between	O
the	O
home	O
network	O
and	O
the	O
Internet	O
.	O
</s>
<s>
connectivity	O
within	O
the	O
home	O
network	O
like	O
a	O
network	B-Protocol
switch	I-Protocol
,	O
hub	B-Protocol
,	O
or	O
WLAN	B-Architecture
base	O
station	O
.	O
</s>
<s>
network	B-Protocol
address	I-Protocol
translation	I-Protocol
(	O
NAT	O
)	O
,	O
</s>
<s>
It	O
may	O
also	O
provide	O
other	O
functions	O
such	O
as	O
Dynamic	B-Protocol
DNS	I-Protocol
,	O
and	O
converged	O
triple	B-Architecture
play	I-Architecture
services	O
such	O
as	O
TV	B-Operating_System
and	O
telephony	O
.	O
</s>
<s>
They	O
are	O
generally	O
platform-independent	O
,	O
i.e.	O
,	O
they	O
can	O
serve	O
any	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Wireless	B-Device
routers	I-Device
perform	O
the	O
same	O
functions	O
as	O
a	O
wired	B-Protocol
router	I-Protocol
and	O
base	O
station	O
,	O
but	O
allowing	O
connectivity	O
for	O
wireless	O
devices	O
with	O
the	O
LAN	B-General_Concept
,	O
or	O
as	O
a	O
bridge	B-Protocol
between	O
the	O
wireless	B-Device
router	I-Device
and	O
another	O
wireless	B-Device
router	I-Device
for	O
a	O
meshnet	B-Architecture
(	O
the	O
wireless	O
router-wireless	O
router	O
connection	O
can	O
be	O
within	O
the	O
LAN	B-General_Concept
or	O
can	O
be	O
between	O
the	O
LAN	B-General_Concept
and	O
WWAN	B-General_Concept
)	O
.	O
</s>
<s>
A	O
majority	O
of	O
the	O
vulnerabilities	O
were	O
present	O
in	O
the	O
web	O
administration	O
frontends	O
of	O
the	O
routers	B-Protocol
,	O
allowing	O
unauthorized	O
control	O
either	O
via	O
default	O
passwords	O
,	O
vendor	O
backdoors	O
,	O
or	O
web	O
vulnerabilities	O
.	O
</s>
