<s>
Universal	B-Application
Plug	I-Application
and	I-Application
Play	I-Application
(	O
UPnP	B-Application
)	O
is	O
a	O
set	O
of	O
networking	O
protocols	O
that	O
permits	O
networked	O
devices	O
,	O
such	O
as	O
personal	B-Device
computers	I-Device
,	O
printers	O
,	O
Internet	B-Application
gateways	I-Application
,	O
Wi-Fi	O
access	O
points	O
and	O
mobile	O
devices	O
to	O
seamlessly	O
discover	O
each	O
other	O
's	O
presence	O
on	O
the	O
network	O
and	O
establish	O
functional	O
network	O
services	O
.	O
</s>
<s>
UPnP	B-Application
is	O
intended	O
primarily	O
for	O
residential	O
networks	B-Architecture
without	O
enterprise-class	O
devices	O
.	O
</s>
<s>
The	O
UPnP	B-Application
protocols	O
were	O
promoted	O
by	O
the	O
UPnP	B-Application
Forum	I-Application
,	O
a	O
computer	O
industry	O
initiative	O
to	O
enable	O
simple	O
and	O
robust	O
connectivity	O
to	O
standalone	O
devices	O
and	O
personal	B-Device
computers	I-Device
from	O
many	O
different	O
vendors	O
.	O
</s>
<s>
Since	O
2016	O
,	O
all	O
UPnP	B-Application
efforts	O
have	O
been	O
managed	O
by	O
the	O
Open	O
Connectivity	O
Foundation	O
(	O
OCF	O
)	O
.	O
</s>
<s>
UPnP	B-Application
assumes	O
the	O
network	O
runs	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IP	O
)	O
and	O
then	O
leverages	O
HTTP	B-Protocol
,	O
on	O
top	O
of	O
IP	O
,	O
in	O
order	O
to	O
provide	O
device/service	O
description	O
,	O
actions	O
,	O
data	O
transfer	O
and	O
event	O
notification	O
.	O
</s>
<s>
Device	O
search	O
requests	O
and	O
advertisements	O
are	O
supported	O
by	O
running	O
HTTP	B-Protocol
on	O
top	O
of	O
UDP	B-Protocol
(	O
port	B-Protocol
1900	O
)	O
using	O
multicast	O
(	O
known	O
as	O
HTTPMU	O
)	O
.	O
</s>
<s>
Responses	O
to	O
search	O
requests	O
are	O
also	O
sent	O
over	O
UDP	B-Protocol
,	O
but	O
are	O
instead	O
sent	O
using	O
unicast	B-Protocol
(	O
known	O
as	O
HTTPU	O
)	O
.	O
</s>
<s>
Conceptually	O
,	O
UPnP	B-Application
extends	O
plug	B-Device
and	I-Device
play	I-Device
—	O
a	O
technology	O
for	O
dynamically	O
attaching	O
devices	O
directly	O
to	O
a	O
computer	O
—	O
to	O
zero-configuration	B-Application
networking	I-Application
for	O
residential	O
and	O
SOHO	O
wireless	O
networks	B-Architecture
.	O
</s>
<s>
UPnP	B-Application
devices	O
are	O
plug	B-Device
and	I-Device
play	I-Device
in	O
that	O
,	O
when	O
connected	O
to	O
a	O
network	O
,	O
they	O
automatically	O
establish	O
working	O
configurations	O
with	O
other	O
devices	O
.	O
</s>
<s>
UPnP	B-Application
is	O
generally	O
regarded	O
as	O
unsuitable	O
for	O
deployment	O
in	O
business	O
settings	O
for	O
reasons	O
of	O
economy	O
,	O
complexity	O
,	O
and	O
consistency	O
:	O
the	O
multicast	O
foundation	O
makes	O
it	O
chatty	O
,	O
consuming	O
too	O
many	O
network	O
resources	O
on	O
networks	B-Architecture
with	O
a	O
large	O
population	O
of	O
devices	O
;	O
the	O
simplified	O
access	O
controls	O
do	O
n't	O
map	O
well	O
to	O
complex	O
environments	O
;	O
and	O
it	O
does	O
not	O
provide	O
a	O
uniform	O
configuration	O
syntax	O
such	O
as	O
the	O
CLI	O
environments	O
of	O
Cisco	O
IOS	O
or	O
JUNOS	O
.	O
</s>
<s>
The	O
UPnP	B-Application
architecture	O
allows	O
device-to-device	O
networking	O
of	O
consumer	O
electronics	O
,	O
mobile	O
devices	O
,	O
personal	B-Device
computers	I-Device
,	O
and	O
networked	O
home	O
appliances	O
.	O
</s>
<s>
It	O
is	O
a	O
distributed	O
,	O
open	B-Architecture
architecture	I-Architecture
protocol	O
based	O
on	O
established	O
standards	O
such	O
as	O
the	O
Internet	B-Protocol
Protocol	I-Protocol
Suite	I-Protocol
(	O
TCP/IP	B-Protocol
)	O
,	O
HTTP	B-Protocol
,	O
XML	B-Protocol
,	O
and	O
SOAP	B-Protocol
.	O
</s>
<s>
UPnP	B-Application
control	O
points	O
(	O
CPs	O
)	O
are	O
devices	O
which	O
use	O
UPnP	B-Application
protocols	O
to	O
control	O
UPnP	B-Application
controlled	O
devices	O
(	O
CDs	O
)	O
.	O
</s>
<s>
The	O
UPnP	B-Application
architecture	O
supports	O
zero-configuration	B-Application
networking	I-Application
.	O
</s>
<s>
A	O
UPnP-compatible	O
device	O
from	O
any	O
vendor	O
can	O
dynamically	O
join	O
a	O
network	O
,	O
obtain	O
an	O
IP	O
address	O
,	O
announce	O
its	O
name	O
,	O
advertise	O
or	O
convey	O
its	O
capabilities	O
upon	O
request	O
,	O
and	O
learn	O
about	O
the	O
presence	O
and	O
capabilities	O
of	O
other	O
devices	O
.	O
</s>
<s>
Dynamic	B-Protocol
Host	I-Protocol
Configuration	I-Protocol
Protocol	I-Protocol
(	O
DHCP	B-Protocol
)	O
and	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
(	O
DNS	B-Protocol
)	O
servers	O
are	O
optional	O
and	O
are	O
only	O
used	O
if	O
they	O
are	O
available	O
on	O
the	O
network	O
.	O
</s>
<s>
Devices	O
can	O
disconnect	O
from	O
the	O
network	O
automatically	O
without	O
leaving	O
state	B-Application
information	O
.	O
</s>
<s>
UPnP	B-Application
was	O
published	O
as	O
a	O
73-part	O
international	O
standard	O
,	O
ISO/IEC	O
29341	O
,	O
in	O
December	O
2008	O
.	O
</s>
<s>
Other	O
UPnP	B-Application
features	O
include	O
:	O
</s>
<s>
Media	O
and	O
device	O
independence	O
UPnP	B-Application
technology	O
can	O
run	O
on	O
many	O
media	O
that	O
support	O
IP	O
including	O
Ethernet	O
,	O
FireWire	B-Protocol
,	O
IR	O
(	O
IrDA	O
)	O
,	O
home	O
wiring	O
(	O
G.hn	B-General_Concept
)	O
and	O
RF	O
(	O
Bluetooth	B-Protocol
,	O
Wi-Fi	O
)	O
.	O
</s>
<s>
No	O
special	O
device	B-Application
driver	I-Application
support	O
is	O
necessary	O
;	O
common	O
network	O
protocols	O
are	O
used	O
instead	O
.	O
</s>
<s>
User	B-Application
interface	I-Application
(	O
UI	O
)	O
Control	O
Optionally	O
,	O
the	O
UPnP	B-Application
architecture	O
enables	O
devices	O
to	O
present	O
a	O
user	B-Application
interface	I-Application
through	O
a	O
web	B-Application
browser	I-Application
(	O
see	O
Presentation	O
below	O
)	O
.	O
</s>
<s>
Operating	B-General_Concept
system	I-General_Concept
and	O
programming	O
language	O
independence	O
Any	O
operating	B-General_Concept
system	I-General_Concept
and	O
any	O
programming	O
language	O
can	O
be	O
used	O
to	O
build	O
UPnP	B-Application
products	O
.	O
</s>
<s>
UPnP	B-Application
stacks	O
are	O
available	O
for	O
most	O
platforms	O
and	O
operating	B-General_Concept
systems	I-General_Concept
in	O
both	O
closed	O
and	O
open	O
source	O
forms	O
.	O
</s>
<s>
Programmatic	O
control	O
UPnP	B-Application
architecture	O
also	O
enables	O
conventional	O
application	O
programmatic	O
control	O
.	O
</s>
<s>
Extensibility	O
Each	O
UPnP	B-Application
product	O
can	O
have	O
device-specific	O
services	O
layered	O
on	O
top	O
of	O
the	O
basic	O
architecture	O
.	O
</s>
<s>
In	O
addition	O
to	O
combining	O
services	O
defined	O
by	O
UPnP	B-Application
Forum	I-Application
in	O
various	O
ways	O
,	O
vendors	O
can	O
define	O
their	O
own	O
device	O
and	O
service	O
types	O
,	O
and	O
can	O
extend	O
standard	O
devices	O
and	O
services	O
with	O
vendor-defined	O
actions	O
,	O
state	B-Application
variables	O
,	O
data	O
structure	O
elements	O
,	O
and	O
variable	O
values	O
.	O
</s>
<s>
UPnP	B-Application
uses	O
common	O
Internet	B-Architecture
technologies	I-Architecture
.	O
</s>
<s>
It	O
assumes	O
the	O
network	O
must	O
run	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IP	O
)	O
and	O
then	O
uses	O
HTTP	B-Protocol
,	O
SOAP	B-Protocol
and	O
XML	B-Protocol
on	O
top	O
of	O
IP	O
,	O
in	O
order	O
to	O
provide	O
device/service	O
description	O
,	O
actions	O
,	O
data	O
transfer	O
and	O
eventing	O
.	O
</s>
<s>
Device	O
search	O
requests	O
and	O
advertisements	O
are	O
supported	O
by	O
running	O
HTTP	B-Protocol
on	O
top	O
of	O
UDP	B-Protocol
using	O
multicast	O
(	O
known	O
as	O
HTTPMU	O
)	O
.	O
</s>
<s>
Responses	O
to	O
search	O
requests	O
are	O
also	O
sent	O
over	O
UDP	B-Protocol
,	O
but	O
are	O
instead	O
sent	O
using	O
unicast	B-Protocol
(	O
known	O
as	O
HTTPU	O
)	O
.	O
</s>
<s>
UPnP	B-Application
uses	O
UDP	B-Protocol
due	O
to	O
its	O
lower	O
overhead	O
in	O
not	O
requiring	O
confirmation	O
of	O
received	O
data	O
and	O
retransmission	O
of	O
corrupt	O
packets	O
.	O
</s>
<s>
HTTPU	O
and	O
HTTPMU	O
were	O
initially	O
submitted	O
as	O
an	O
Internet	O
Draft	O
but	O
it	O
expired	O
in	O
2001	O
;	O
these	O
specifications	O
have	O
since	O
been	O
integrated	O
into	O
the	O
actual	O
UPnP	B-Application
specifications	O
.	O
</s>
<s>
UPnP	B-Application
uses	O
UDP	B-Protocol
port	B-Protocol
1900	O
and	O
all	O
used	O
TCP	B-Protocol
ports	I-Protocol
are	O
derived	O
from	O
the	O
SSDP	O
alive	O
and	O
response	O
messages	O
.	O
</s>
<s>
The	O
foundation	O
for	O
UPnP	B-Application
networking	O
is	O
IP	O
addressing	O
.	O
</s>
<s>
Each	O
device	O
must	O
implement	O
a	O
DHCP	B-Protocol
client	O
and	O
search	O
for	O
a	O
DHCP	B-Protocol
server	I-Protocol
when	O
the	O
device	O
is	O
first	O
connected	O
to	O
the	O
network	O
.	O
</s>
<s>
If	O
no	O
DHCP	B-Protocol
server	I-Protocol
is	O
available	O
,	O
the	O
device	O
must	O
assign	O
itself	O
an	O
address	O
.	O
</s>
<s>
The	O
process	O
by	O
which	O
a	O
UPnP	B-Application
device	O
assigns	O
itself	O
an	O
address	O
is	O
known	O
within	O
the	O
UPnP	B-Application
Device	O
Architecture	O
as	O
AutoIP	B-Protocol
.	O
</s>
<s>
In	O
UPnP	B-Application
Device	O
Architecture	O
Version	O
1.0	O
,	O
AutoIP	B-Protocol
is	O
defined	O
within	O
the	O
specification	O
itself	O
;	O
in	O
UPnP	B-Application
Device	O
Architecture	O
Version	O
1.1	O
,	O
AutoIP	B-Protocol
references	O
IETF	O
RFC	O
3927	O
.	O
</s>
<s>
If	O
during	O
the	O
DHCP	B-Protocol
transaction	O
,	O
the	O
device	O
obtains	O
a	O
domain	O
name	O
,	O
for	O
example	O
,	O
through	O
a	O
DNS	B-Protocol
server	O
or	O
via	O
DNS	B-Protocol
forwarding	O
,	O
the	O
device	O
should	O
use	O
that	O
name	O
in	O
subsequent	O
network	O
operations	O
;	O
otherwise	O
,	O
the	O
device	O
should	O
use	O
its	O
IP	O
address	O
.	O
</s>
<s>
Once	O
a	O
device	O
has	O
established	O
an	O
IP	O
address	O
,	O
the	O
next	O
step	O
in	O
UPnP	B-Application
networking	O
is	O
discovery	O
.	O
</s>
<s>
The	O
UPnP	B-Application
discovery	O
protocol	O
is	O
known	O
as	O
the	O
Simple	B-Protocol
Service	I-Protocol
Discovery	I-Protocol
Protocol	I-Protocol
(	O
SSDP	O
)	O
.	O
</s>
<s>
The	O
UPnP	B-Application
Device	O
Description	O
is	O
expressed	O
in	O
XML	B-Protocol
and	O
includes	O
vendor-specific	O
manufacturer	O
information	O
like	O
the	O
model	O
name	O
and	O
number	O
,	O
serial	O
number	O
,	O
manufacturer	O
name	O
,	O
(	O
presentation	O
)	O
URLs	O
to	O
vendor-specific	O
web	O
sites	O
,	O
etc	O
.	O
</s>
<s>
Each	O
service	O
description	O
includes	O
a	O
list	O
of	O
the	O
commands	B-Application
,	O
or	O
actions	O
,	O
to	O
which	O
the	O
service	O
responds	O
,	O
and	O
parameters	O
,	O
or	O
arguments	O
,	O
for	O
each	O
action	O
;	O
the	O
description	O
for	O
a	O
service	O
also	O
includes	O
a	O
list	O
of	O
variables	O
;	O
these	O
variables	O
model	O
the	O
state	B-Application
of	O
the	O
service	O
at	O
run	B-Library
time	I-Library
,	O
and	O
are	O
described	O
in	O
terms	O
of	O
their	O
data	O
type	O
,	O
range	O
,	O
and	O
event	O
characteristics	O
.	O
</s>
<s>
Control	O
messages	O
are	O
also	O
expressed	O
in	O
XML	B-Protocol
using	O
the	O
Simple	B-Protocol
Object	I-Protocol
Access	I-Protocol
Protocol	I-Protocol
(	O
SOAP	B-Protocol
)	O
.	O
</s>
<s>
The	O
effects	O
of	O
the	O
action	O
,	O
if	O
any	O
,	O
are	O
modeled	O
by	O
changes	O
in	O
the	O
variables	O
that	O
describe	O
the	O
run-time	O
state	B-Application
of	O
the	O
service	O
.	O
</s>
<s>
Another	O
capability	O
of	O
UPnP	B-Application
networking	O
is	O
event	O
notification	O
,	O
or	O
eventing	O
.	O
</s>
<s>
The	O
event	O
notification	O
protocol	O
defined	O
in	O
the	O
UPnP	B-Application
Device	O
Architecture	O
is	O
known	O
as	O
General	B-Protocol
Event	I-Protocol
Notification	I-Protocol
Architecture	I-Protocol
(	O
GENA	B-Protocol
)	O
.	O
</s>
<s>
A	O
UPnP	B-Application
description	O
for	O
a	O
service	O
includes	O
a	O
list	O
of	O
actions	O
the	O
service	O
responds	O
to	O
and	O
a	O
list	O
of	O
variables	O
that	O
model	O
the	O
state	B-Application
of	O
the	O
service	O
at	O
run	B-Library
time	I-Library
.	O
</s>
<s>
Event	O
messages	O
contain	O
the	O
names	O
of	O
one	O
or	O
more	O
state	B-Application
variables	O
and	O
the	O
current	O
value	O
of	O
those	O
variables	O
.	O
</s>
<s>
These	O
messages	O
are	O
also	O
expressed	O
in	O
XML	B-Protocol
.	O
</s>
<s>
A	O
special	O
initial	O
event	O
message	O
is	O
sent	O
when	O
a	O
control	O
point	O
first	O
subscribes	O
;	O
this	O
event	O
message	O
contains	O
the	O
names	O
and	O
values	O
for	O
all	O
evented	O
variables	O
and	O
allows	O
the	O
subscriber	O
to	O
initialize	O
its	O
model	O
of	O
the	O
state	B-Application
of	O
the	O
service	O
.	O
</s>
<s>
Therefore	O
,	O
all	O
subscribers	O
are	O
sent	O
all	O
event	O
messages	O
,	O
subscribers	O
receive	O
event	O
messages	O
for	O
all	O
"	O
evented	O
"	O
variables	O
that	O
have	O
changed	O
,	O
and	O
event	O
messages	O
are	O
sent	O
no	O
matter	O
why	O
the	O
state	B-Application
variable	O
changed	O
(	O
either	O
in	O
response	O
to	O
a	O
requested	O
action	O
or	O
because	O
the	O
state	B-Application
the	O
service	O
is	O
modeling	O
changed	O
)	O
.	O
</s>
<s>
The	O
final	O
step	O
in	O
UPnP	B-Application
networking	O
is	O
presentation	O
.	O
</s>
<s>
If	O
a	O
device	O
has	O
a	O
URL	O
for	O
presentation	O
,	O
then	O
the	O
control	O
point	O
can	O
retrieve	O
a	O
page	O
from	O
this	O
URL	O
,	O
load	O
the	O
page	O
into	O
a	O
web	B-Application
browser	I-Application
,	O
and	O
depending	O
on	O
the	O
capabilities	O
of	O
the	O
page	O
,	O
allow	O
a	O
user	O
to	O
control	O
the	O
device	O
and/or	O
view	O
device	O
status	O
.	O
</s>
<s>
UPnP	B-Application
AV	O
architecture	O
is	O
an	O
audio	O
and	O
video	O
extension	O
of	O
the	O
UPnP	B-Application
,	O
supporting	O
a	O
variety	O
of	O
devices	O
such	O
as	O
TVs	O
,	O
VCRs	O
,	O
CD/DVD	O
players/jukeboxes	O
,	O
settop	O
boxes	O
,	O
stereos	O
systems	O
,	O
MP3	O
players	O
,	O
still	O
image	O
cameras	O
,	O
camcorders	O
,	O
electronic	O
picture	O
frames	O
(	O
EPFs	O
)	O
,	O
and	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
The	O
UPnP	B-Application
AV	O
architecture	O
allows	O
devices	O
to	O
support	O
different	O
types	O
of	O
formats	O
for	O
the	O
entertainment	O
content	O
,	O
including	O
MPEG2	O
,	O
MPEG4	O
,	O
JPEG	O
,	O
MP3	O
,	O
Windows	O
Media	O
Audio	O
(	O
WMA	O
)	O
,	O
bitmaps	O
(	O
BMP	O
)	O
,	O
and	O
NTSC	O
,	O
PAL	O
or	O
ATSC	O
formats	O
.	O
</s>
<s>
Multiple	O
types	O
of	O
transfer	O
protocols	O
are	O
supported	O
,	O
including	O
IEEE	B-Protocol
1394	I-Protocol
,	O
HTTP	B-Protocol
,	O
RTP	O
and	O
TCP/IP	B-Protocol
.	O
</s>
<s>
On	O
12	O
July	O
2006	O
,	O
the	O
UPnP	B-Application
Forum	I-Application
announced	O
the	O
release	O
of	O
version	O
2	O
of	O
the	O
UPnP	B-Application
Audio	O
and	O
Video	O
specifications	O
,	O
with	O
new	O
MediaServer	O
(	O
MS	O
)	O
version	O
2.0	O
and	O
MediaRenderer	O
(	O
MR	O
)	O
version	O
2.0	O
classes	O
.	O
</s>
<s>
Since	O
2006	O
,	O
versions	O
3	O
and	O
4	O
of	O
the	O
UPnP	B-Application
audio	O
and	O
video	O
device	O
control	O
protocols	O
have	O
been	O
published	O
.	O
</s>
<s>
In	O
March	O
2013	O
,	O
an	O
updated	O
uPnP	B-Application
AV	O
architecture	O
specification	O
was	O
published	O
,	O
incorporating	O
the	O
updated	O
device	O
control	O
protocols	O
.	O
</s>
<s>
The	O
UPnP	B-Application
AV	O
standards	O
have	O
been	O
referenced	O
in	O
specifications	O
published	O
by	O
other	O
organizations	O
including	O
Digital	O
Living	O
Network	O
Alliance	O
Networked	O
Device	O
Interoperability	O
Guidelines	O
,	O
International	O
Electrotechnical	O
Commission	O
IEC	O
62481-1	O
,	O
and	O
Cable	O
Television	O
Laboratories	O
OpenCable	O
Home	B-Architecture
Networking	I-Architecture
Protocol	O
.	O
</s>
<s>
A	O
is	O
the	O
UPnP-server	O
(	O
"	O
master	O
"	O
device	O
)	O
that	O
provides	O
media	O
library	O
information	O
and	O
streams	O
media-data	O
(	O
like	O
audio/video/picture/files	O
)	O
to	O
UPnP	B-Application
clients	O
on	O
the	O
network	O
.	O
</s>
<s>
UPnP	B-Application
AV	O
media	O
servers	O
provide	O
a	O
service	O
to	O
UPnP	B-Application
AV	O
client	O
devices	O
,	O
so-called	O
control	O
points	O
,	O
for	O
browsing	O
the	O
media	O
content	O
of	O
the	O
server	O
and	O
request	O
the	O
media	O
server	O
to	O
deliver	O
a	O
file	O
to	O
the	O
control	O
point	O
for	O
playback	O
.	O
</s>
<s>
UPnP	B-Application
media	O
servers	O
are	O
available	O
for	O
most	O
operating	B-General_Concept
systems	I-General_Concept
and	O
many	O
hardware	O
platforms	O
.	O
</s>
<s>
UPnP	B-Application
AV	O
media	O
servers	O
can	O
either	O
be	O
categorized	O
as	O
software-based	O
or	O
hardware-based	O
.	O
</s>
<s>
Software-based	O
UPnP	B-Application
AV	O
media	O
servers	O
can	O
be	O
run	O
on	O
a	O
PC	B-Device
.	O
</s>
<s>
Hardware-based	O
UPnP	B-Application
AV	O
media	O
servers	O
may	O
run	O
on	O
any	O
NAS	B-Application
devices	O
or	O
any	O
specific	O
hardware	O
for	O
delivering	O
media	O
,	O
such	O
as	O
a	O
DVR	B-Application
.	O
</s>
<s>
As	O
of	O
May	O
2008	O
,	O
there	O
were	O
more	O
software-based	O
UPnP	B-Application
AV	O
media	O
servers	O
than	O
there	O
were	O
hardware-based	O
servers	O
.	O
</s>
<s>
UPnP	B-Application
MediaServer	O
ControlPoint	O
-	O
which	O
is	O
the	O
UPnP-client	O
(	O
a	O
'	O
slave	O
 '	O
device	O
)	O
that	O
can	O
auto-detect	O
UPnP-servers	O
on	O
the	O
network	O
to	O
browse	O
and	O
stream	O
media/data	O
-files	O
from	O
them	O
.	O
</s>
<s>
UPnP	B-Application
MediaRenderer	O
DCP	O
-	O
which	O
is	O
a	O
'	O
slave	O
 '	O
device	O
that	O
can	O
render	O
(	O
play	O
)	O
content	O
.	O
</s>
<s>
UPnP	B-Application
RenderingControl	O
DCP	O
-	O
control	O
MediaRenderer	O
settings	O
;	O
volume	O
,	O
brightness	O
,	O
RGB	O
,	O
sharpness	O
,	O
and	O
more	O
.	O
</s>
<s>
UPnP	B-Application
Remote	O
User	B-Application
Interface	I-Application
(	O
RUI	O
)	O
client/server	O
-	O
which	O
sends/receives	O
control-commands	O
between	O
the	O
UPnP-client	O
and	O
UPnP-server	O
over	O
network	O
,	O
(	O
like	O
record	O
,	O
schedule	O
,	O
play	O
,	O
pause	O
,	O
stop	O
,	O
etc	O
.	O
</s>
<s>
Web4CE	O
(	O
CEA	O
2014	O
)	O
for	O
UPnP	B-Application
Remote	O
UI	O
-	O
CEA-2014	O
standard	O
designed	O
by	O
Consumer	O
Electronics	O
Association	O
's	O
R7	O
Home	O
Network	O
Committee	O
.	O
</s>
<s>
Web-based	O
Protocol	O
and	O
Framework	B-Architecture
for	O
Remote	O
User	B-Application
Interface	I-Application
on	O
UPnP	B-Application
Networks	B-Architecture
and	O
the	O
Internet	O
(	O
Web4CE	O
)	O
.	O
</s>
<s>
This	O
standard	O
allows	O
a	O
UPnP-capable	O
home	O
network	O
device	O
to	O
provide	O
its	O
interface	B-Application
(	O
display	O
and	O
control	O
options	O
)	O
as	O
a	O
web	O
page	O
to	O
display	O
on	O
any	O
other	O
device	O
connected	O
to	O
the	O
home	O
network	O
.	O
</s>
<s>
That	O
means	O
that	O
one	O
can	O
control	O
a	O
home	B-Architecture
networking	I-Architecture
device	O
through	O
any	O
web-browser-based	O
communications	O
method	O
for	O
CE	O
devices	O
on	O
a	O
UPnP	B-Application
home	O
network	O
using	O
ethernet	O
and	O
a	O
special	O
version	O
of	O
HTML	B-Language
called	O
CE-HTML	B-General_Concept
.	O
</s>
<s>
QoS	O
(	O
quality	O
of	O
service	O
)	O
-	O
is	O
an	O
important	O
(	O
but	O
not	O
mandatory	O
)	O
service	O
function	O
for	O
use	O
with	O
UPnP	B-Application
AV	O
(	O
Audio	O
and	O
Video	O
)	O
.	O
</s>
<s>
Since	O
UPnP	B-Application
AV	O
is	O
mostly	O
to	O
deliver	O
streaming	O
media	O
that	O
is	O
often	O
near	O
real-time	O
or	O
real-time	O
audio/video	O
data	O
which	O
it	O
is	O
critical	O
to	O
be	O
delivered	O
within	O
a	O
specific	O
time	O
or	O
the	O
stream	O
is	O
interrupted	O
.	O
</s>
<s>
QoS	O
guarantees	O
are	O
especially	O
important	O
if	O
the	O
network	O
capacity	O
is	O
limited	O
,	O
for	O
example	O
public	O
networks	B-Architecture
,	O
like	O
the	O
internet	O
.	O
</s>
<s>
QoS	O
for	O
UPnP	B-Application
consist	O
of	O
Sink	O
Device	O
(	O
client-side/front	O
-end	O
)	O
and	O
Source	O
Device	O
(	O
server-side/back	O
-end	O
)	O
service	O
functions	O
.	O
</s>
<s>
Remote	O
Access	O
-	O
defines	O
methods	O
for	O
connecting	O
UPnP	B-Application
device	O
sets	O
that	O
are	O
not	O
in	O
the	O
same	O
multicast	O
domain	O
.	O
</s>
<s>
One	O
solution	O
for	O
NAT	B-Protocol
traversal	I-Protocol
,	O
called	O
the	O
Internet	B-Protocol
Gateway	I-Protocol
Device	I-Protocol
Protocol	I-Protocol
(	O
IGD	O
Protocol	O
)	O
,	O
is	O
implemented	O
via	O
UPnP	B-Application
.	O
</s>
<s>
Many	O
routers	B-Protocol
and	O
firewalls	B-Application
expose	O
themselves	O
as	O
Internet	B-Protocol
Gateway	I-Protocol
Devices	I-Protocol
,	O
allowing	O
any	O
local	O
UPnP	B-Application
control	O
point	O
to	O
perform	O
a	O
variety	O
of	O
actions	O
,	O
including	O
retrieving	O
the	O
external	O
IP	O
address	O
of	O
the	O
device	O
,	O
enumerating	O
existing	O
port	B-Protocol
mappings	O
,	O
and	O
adding	O
or	O
removing	O
port	B-Protocol
mappings	O
.	O
</s>
<s>
By	O
adding	O
a	O
port	B-Protocol
mapping	O
,	O
a	O
UPnP	B-Application
controller	O
behind	O
the	O
IGD	O
can	O
enable	O
traversal	O
of	O
the	O
IGD	O
from	O
an	O
external	O
address	O
to	O
an	O
internal	O
client	O
.	O
</s>
<s>
The	O
UPnP	B-Application
protocol	O
,	O
by	O
default	O
,	O
does	O
not	O
implement	O
any	O
authentication	O
,	O
so	O
UPnP	B-Application
device	O
implementations	O
must	O
implement	O
the	O
additional	O
Device	O
Protection	O
service	O
,	O
or	O
implement	O
the	O
Device	O
Security	O
Service	O
.	O
</s>
<s>
There	O
also	O
exists	O
a	O
non-standard	O
solution	O
called	O
UPnP-UP	O
(	O
Universal	B-Application
Plug	I-Application
and	I-Application
Play	I-Application
-	O
User	O
Profile	O
)	O
which	O
proposes	O
an	O
extension	O
to	O
allow	O
user	O
authentication	O
and	O
authorization	O
mechanisms	O
for	O
UPnP	B-Application
devices	O
and	O
applications	O
.	O
</s>
<s>
Many	O
UPnP	B-Application
device	O
implementations	O
lack	O
authentication	O
mechanisms	O
,	O
and	O
by	O
default	O
assume	O
local	O
systems	O
and	O
their	O
users	O
are	O
completely	O
trustworthy	O
.	O
</s>
<s>
When	O
the	O
authentication	O
mechanisms	O
are	O
not	O
implemented	O
,	O
routers	B-Protocol
and	O
firewalls	B-Application
running	O
the	O
UPnP	B-Application
IGD	O
protocol	O
are	O
vulnerable	O
to	O
attack	O
.	O
</s>
<s>
For	O
example	O
,	O
Adobe	B-Operating_System
Flash	I-Operating_System
programs	O
running	O
outside	O
the	O
sandbox	O
of	O
the	O
browser	B-Application
(	O
e.g.	O
</s>
<s>
this	O
requires	O
specific	O
version	O
of	O
Adobe	B-Operating_System
Flash	I-Operating_System
with	O
acknowledged	O
security	O
issues	O
)	O
are	O
capable	O
of	O
generating	O
a	O
specific	O
type	O
of	O
HTTP	B-Protocol
request	O
which	O
allows	O
a	O
router	B-Protocol
implementing	O
the	O
UPnP	B-Application
IGD	O
protocol	O
to	O
be	O
controlled	O
by	O
a	O
malicious	O
web	O
site	O
when	O
someone	O
with	O
a	O
UPnP-enabled	O
router	B-Protocol
simply	O
visits	O
that	O
web	O
site	O
.	O
</s>
<s>
This	O
only	O
applies	O
to	O
the	O
"	O
firewall-hole-punching	O
"	O
-feature	O
of	O
UPnP	B-Application
;	O
it	O
does	O
not	O
apply	O
when	O
the	O
IGD	O
does	O
not	O
support	O
UPnP	B-Application
or	O
UPnP	B-Application
has	O
been	O
disabled	O
on	O
the	O
IGD	O
.	O
</s>
<s>
Also	O
,	O
not	O
all	O
routers	B-Protocol
can	O
have	O
such	O
things	O
as	O
DNS	B-Protocol
server	O
settings	O
altered	O
by	O
UPnP	B-Application
because	O
much	O
of	O
the	O
specification	O
(	O
including	O
LAN	O
Host	O
Configuration	O
)	O
is	O
optional	O
for	O
UPnP	B-Application
enabled	O
routers	B-Protocol
.	O
</s>
<s>
As	O
a	O
result	O
,	O
some	O
UPnP	B-Application
devices	O
ship	O
with	O
UPnP	B-Application
turned	O
off	O
by	O
default	O
as	O
a	O
security	O
measure	O
.	O
</s>
<s>
In	O
2011	O
,	O
researcher	O
Daniel	O
Garcia	O
developed	O
a	O
tool	O
designed	O
to	O
exploit	O
a	O
flaw	O
in	O
some	O
UPnP	B-Application
IGD	O
device	O
stacks	O
that	O
allow	O
UPnP	B-Application
requests	O
from	O
the	O
Internet	O
.	O
</s>
<s>
A	O
team	O
scanned	O
for	O
signals	O
from	O
UPnP-enabled	O
devices	O
announcing	O
their	O
availability	O
for	O
internet	O
connection	O
.	O
</s>
<s>
80%	O
of	O
the	O
devices	O
are	O
home	O
routers	B-Protocol
;	O
others	O
include	O
printers	O
,	O
webcams	O
and	O
surveillance	O
cameras	O
.	O
</s>
<s>
Using	O
the	O
UPnP-protocol	O
,	O
many	O
of	O
those	O
devices	O
can	O
be	O
accessed	O
and/or	O
manipulated	O
.	O
</s>
<s>
In	O
February	O
2013	O
,	O
the	O
UPnP	B-Application
forum	I-Application
responded	O
in	O
a	O
press	O
release	O
by	O
recommending	O
more	O
recent	O
versions	O
of	O
the	O
used	O
UPnP	B-Application
stacks	O
,	O
and	O
by	O
improving	O
the	O
certification	O
program	O
to	O
include	O
checks	O
to	O
avoid	O
further	O
such	O
issues	O
.	O
</s>
<s>
UPnP	B-Application
is	O
often	O
the	O
only	O
significant	O
multicast	O
application	O
in	O
use	O
in	O
digital	O
home	O
networks	B-Architecture
;	O
therefore	O
,	O
multicast	O
network	O
misconfiguration	O
or	O
other	O
deficiencies	O
can	O
appear	O
as	O
UPnP	B-Application
issues	O
rather	O
than	O
underlying	O
network	O
issues	O
.	O
</s>
<s>
If	O
IGMP	B-Protocol
snooping	I-Protocol
is	O
enabled	O
on	O
a	O
switch	O
,	O
or	O
more	O
commonly	O
a	O
wireless	O
router/switch	O
,	O
it	O
will	O
interfere	O
with	O
UPnP/DLNA	O
device	O
discovery	O
(	O
SSDP	O
)	O
if	O
incorrectly	O
or	O
incompletely	O
configured	O
(	O
e.g.	O
</s>
<s>
without	O
an	O
active	O
querier	O
or	O
IGMP	O
proxy	O
)	O
,	O
making	O
UPnP	B-Application
appear	O
unreliable	O
.	O
</s>
<s>
OCF	O
had	O
published	O
a	O
fix	O
to	O
the	O
protocol	O
specification	O
in	O
April	O
2020	O
,	O
but	O
since	O
many	O
devices	O
running	O
UPnP	B-Application
are	O
not	O
easily	O
upgradable	O
,	O
CallStranger	O
is	O
likely	O
to	O
remain	O
a	O
threat	O
for	O
a	O
long	O
time	O
to	O
come	O
.	O
</s>
<s>
CallStranger	O
has	O
fueled	O
calls	O
for	O
end-users	O
to	O
abandon	O
UPnP	B-Application
because	O
of	O
repeated	O
failures	O
in	O
security	O
of	O
its	O
design	O
and	O
implementation	O
.	O
</s>
<s>
In	O
the	O
fall	O
of	O
2008	O
,	O
the	O
UPnP	B-Application
Forum	I-Application
ratified	O
the	O
successor	O
to	O
UPnP	B-Application
1.0	O
Device	O
Architecture	O
,	O
UPnP	B-Application
1.1	O
.	O
</s>
<s>
The	O
Devices	B-Protocol
Profile	I-Protocol
for	I-Protocol
Web	I-Protocol
Services	I-Protocol
(	O
DPWS	B-Protocol
)	O
standard	O
was	O
a	O
candidate	O
successor	O
to	O
UPnP	B-Application
,	O
but	O
UPnP	B-Application
1.1	O
was	O
selected	O
by	O
the	O
UPnP	B-Application
Forum	I-Application
.	O
</s>
<s>
The	O
UPnP	B-Application
Internet	B-Protocol
Gateway	I-Protocol
Device	I-Protocol
(	O
IGD	O
)	O
standard	O
has	O
a	O
WANIPConnection	O
service	O
,	O
which	O
provides	O
similar	O
functionality	O
to	O
IETF-standard	O
Port	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
that	O
prompted	O
the	O
creation	O
of	O
NAT-PMP	B-Protocol
and	O
its	O
successor	O
PCP	O
.	O
</s>
<s>
A	O
number	O
of	O
further	O
standards	O
have	O
been	O
defined	O
for	O
the	O
UPnP	B-Application
Device	O
Architecture	O
:	O
</s>
<s>
This	O
service	O
is	O
used	O
in	O
the	O
AP-ER	O
and	O
UPnP-C	O
types	O
of	O
Wi-Fi	B-Protocol
Protected	I-Protocol
Setup	I-Protocol
.	O
</s>
