<s>
DirectPlay	B-Protocol
is	O
part	O
of	O
Microsoft	O
's	O
DirectX	B-Application
API	B-General_Concept
.	O
</s>
<s>
It	O
is	O
a	O
network	B-Architecture
communication	O
library	O
intended	O
for	O
computer	O
game	O
development	O
,	O
although	O
it	O
can	O
be	O
used	O
for	O
other	O
purposes	O
.	O
</s>
<s>
DirectPlay	B-Protocol
is	O
a	O
high-level	O
software	O
interface	O
between	O
applications	O
and	O
communication	O
services	O
that	O
allows	O
games	O
to	O
be	O
connected	O
over	O
the	O
Internet	O
,	O
a	O
modem	B-Application
link	O
,	O
or	O
a	O
network	B-Architecture
.	O
</s>
<s>
It	O
also	O
resolves	O
many	O
connectivity	O
issues	O
,	O
such	O
as	O
Network	B-Protocol
Address	I-Protocol
Translation	I-Protocol
(	O
NAT	B-Protocol
)	O
.	O
</s>
<s>
Like	O
the	O
rest	O
of	O
DirectX	B-Application
,	O
DirectPlay	B-Protocol
runs	O
in	O
COM	O
and	O
is	O
accessed	O
through	O
component	B-Application
object	I-Application
model	I-Application
(	O
COM	O
)	O
interfaces	B-Application
.	O
</s>
<s>
By	O
default	O
,	O
DirectPlay	B-Protocol
uses	O
multi-threaded	B-Operating_System
programming	I-Operating_System
techniques	O
and	O
requires	O
careful	O
thought	O
to	O
avoid	O
the	O
usual	O
threading	O
issues	O
.	O
</s>
<s>
Since	O
DirectX	B-Application
version	O
9	O
,	O
this	O
issue	O
can	O
be	O
alleviated	O
at	O
the	O
expense	O
of	O
efficiency	O
.	O
</s>
<s>
Under	O
the	O
hood	O
,	O
DirectPlay	B-Protocol
is	O
built	O
on	O
the	O
User	B-Protocol
Datagram	I-Protocol
Protocol	I-Protocol
(	O
UDP	O
)	O
to	O
allow	O
it	O
speedy	O
communication	O
with	O
other	O
DirectPlay	B-Protocol
applications	O
.	O
</s>
<s>
DirectPlay	B-Protocol
sits	O
on	O
layers	O
4	O
and	O
5	O
of	O
the	O
OSI	O
model	O
.	O
</s>
<s>
On	O
layer	O
4	O
,	O
DirectPlay	B-Protocol
can	O
handle	O
the	O
following	O
tasks	O
if	O
requested	O
by	O
the	O
application	O
:	O
</s>
<s>
Message	O
reliability	B-Protocol
,	O
which	O
ensures	O
that	O
data	O
is	O
guaranteed	O
to	O
arrive	O
.	O
</s>
<s>
On	O
layer	O
5	O
,	O
DirectPlay	B-Protocol
always	O
handles	O
the	O
following	O
tasks	O
:	O
</s>
<s>
The	O
primary	O
interfaces	B-Application
(	O
methods	O
of	O
access	O
)	O
for	O
DirectPlay	B-Protocol
are	O
:	O
</s>
<s>
Secondary	O
interfaces	B-Application
are	O
:	O
</s>
<s>
Various	O
lobby	O
interfaces	B-Application
that	O
allows	O
players	O
to	O
find	O
and	O
prepare	O
a	O
game	O
before	O
it	O
actually	O
commences	O
.	O
</s>
<s>
Thread	B-Operating_System
management	I-Operating_System
interfaces	B-Application
that	O
allows	O
the	O
programmer	O
to	O
fine-tune	O
resource	O
usage	O
.	O
</s>
<s>
This	O
also	O
allows	O
for	O
a	O
general	O
disabling	O
of	O
worker	O
threads	B-Operating_System
so	O
that	O
tricky	O
multi-threaded	B-Operating_System
issues	O
are	O
avoided	O
at	O
the	O
cost	O
of	O
decreased	O
responsiveness	O
.	O
</s>
<s>
Various	O
network	B-Protocol
address	I-Protocol
translation	I-Protocol
(	O
NAT	B-Protocol
)	O
interfaces	B-Application
that	O
make	O
it	O
easier	O
for	O
players	O
behind	O
routers	B-Protocol
to	O
host	O
games	O
.	O
</s>
<s>
Most	O
players	O
on	O
broadband	B-General_Concept
internet	O
connections	O
face	O
this	O
problem	O
.	O
</s>
<s>
Various	O
voice	O
communication	O
interfaces	B-Application
known	O
as	O
DirectPlay	B-Protocol
Voice	O
that	O
make	O
it	O
easier	O
to	O
support	O
audio	O
communication	O
and	O
voice	O
input	O
in	O
games	O
.	O
</s>
<s>
Various	O
queue	O
monitoring	O
interfaces	B-Application
that	O
allow	O
the	O
application	O
to	O
get	O
feedback	O
on	O
how	O
much	O
data	O
has	O
been	O
sent	O
and	O
received	O
as	O
requested	O
.	O
</s>
<s>
DirectPlay	B-Protocol
Voice	O
was	O
introduced	O
in	O
Windows	B-Device
Me	I-Device
as	O
part	O
of	O
DirectX	O
7.1	O
for	O
multiplayer	O
games	O
.	O
</s>
<s>
It	O
is	O
a	O
voice	O
communications	O
,	O
recording	O
and	O
playback	O
API	B-General_Concept
that	O
allows	O
gamers	O
to	O
use	O
voice	B-Protocol
chat	I-Protocol
in	O
games	O
written	O
to	O
take	O
advantage	O
of	O
the	O
API	B-General_Concept
,	O
through	O
a	O
DirectPlay	B-Protocol
network	B-Architecture
transport	O
session	O
itself	O
.	O
</s>
<s>
DirectPlay	B-Protocol
was	O
traditionally	O
one	O
of	O
the	O
components	O
of	O
DirectX	B-Application
that	O
received	O
less	O
attention	O
,	O
but	O
for	O
DirectX	B-Application
version	O
8	O
it	O
received	O
a	O
major	O
overhaul	O
and	O
became	O
a	O
relatively	O
lightweight	O
networking	O
library	O
.	O
</s>
<s>
However	O
,	O
as	O
part	O
of	O
Microsoft	O
's	O
unveiling	O
of	O
XNA	B-Device
in	O
2004	O
,	O
Microsoft	O
revealed	O
that	O
DirectPlay	B-Protocol
would	O
be	O
deprecated	B-General_Concept
in	O
favor	O
of	O
Games	B-Application
for	I-Application
Windows	I-Application
-	I-Application
Live	I-Application
technology	O
already	O
available	O
on	O
Xbox	B-Protocol
and	O
being	O
ported	O
for	O
use	O
on	O
Windows	B-Application
PCs	I-Application
.	O
</s>
<s>
DirectPlay	B-Protocol
will	O
be	O
supported	O
in	O
DirectX	B-Application
DLLs	O
for	O
the	O
lifetime	O
of	O
Microsoft	B-Application
Windows	I-Application
XP	O
,	O
but	O
from	O
the	O
autumn	O
of	O
2007	O
the	O
headers	O
and	O
libraries	O
vital	O
components	O
if	O
developers	O
wanted	O
to	O
develop	O
new	O
programs	O
that	O
utilize	O
the	O
technology	O
were	O
absent	O
from	O
DirectX	B-Application
SDK	O
.	O
</s>
<s>
In	O
Windows	B-Application
Vista	I-Application
,	O
DirectPlay	B-Protocol
has	O
been	O
deprecated	B-General_Concept
and	O
DirectPlay	B-Protocol
Voice	O
and	O
DirectPlay	B-Protocol
's	O
NAT	B-Protocol
Helper	O
have	O
been	O
removed	O
.	O
</s>
