<s>
Traffic	B-General_Concept
indication	I-General_Concept
map	I-General_Concept
(	O
TIM	O
)	O
is	O
a	O
structure	O
used	O
in	O
802.11	O
wireless	O
network	O
management	O
frames	O
.	O
</s>
<s>
The	O
Traffic	B-General_Concept
indication	I-General_Concept
map	I-General_Concept
information	O
element	O
is	O
covered	O
under	O
section	O
7.3.2.6	O
of	O
802.11-1999	O
standard	O
.	O
</s>
<s>
The	O
IEEE	O
802.11	O
standards	O
use	O
a	O
bitmap	O
to	O
indicate	O
to	O
any	O
sleeping	O
listening	O
stations	O
that	O
the	O
Access	B-Device
Point	I-Device
(	O
AP	O
)	O
has	O
buffered	O
data	O
waiting	O
for	O
it	O
.	O
</s>
<s>
The	O
bit	O
mask	O
is	O
called	O
the	O
Traffic	B-General_Concept
Indication	I-General_Concept
Map	I-General_Concept
and	O
consists	O
of	O
2008	O
bits	O
,	O
each	O
bit	O
representing	O
the	O
Association	O
ID	O
(	O
AID	O
)	O
of	O
a	O
station	O
.	O
</s>
<s>
A	O
Delivery	O
Traffic	O
Indication	O
Message	O
(	O
DTIM	O
)	O
is	O
a	O
kind	O
of	O
TIM	O
which	O
informs	O
the	O
clients	O
about	O
the	O
presence	O
of	O
buffered	O
multicast/broadcast	O
data	O
on	O
the	O
access	B-Device
point	I-Device
.	O
</s>
<s>
Beacons	O
are	O
packets	O
sent	O
by	O
an	O
access	B-Device
point	I-Device
to	O
synchronize	O
a	O
wireless	O
network	O
.	O
</s>
<s>
After	O
a	O
DTIM	O
,	O
the	O
access	B-Device
point	I-Device
will	O
send	O
the	O
multicast/broadcast	O
data	O
on	O
the	O
channel	O
following	O
the	O
normal	O
channel	O
access	O
rules	O
(	O
CSMA/CA	O
)	O
.	O
</s>
<s>
A	O
DTIM	O
is	O
included	O
in	O
beacon	O
frames	O
,	O
according	O
to	O
the	O
DTIM	O
period	O
,	O
to	O
indicate	O
to	O
the	O
client	O
devices	O
whether	O
the	O
access	B-Device
point	I-Device
has	O
buffered	O
broadcast	O
and/or	O
multicast	O
data	O
waiting	O
for	O
them	O
.	O
</s>
<s>
Following	O
a	O
beacon	O
frame	O
that	O
includes	O
a	O
DTIM	O
,	O
the	O
access	B-Device
point	I-Device
will	O
release	O
the	O
buffered	O
broadcast	O
and/or	O
multicast	O
data	O
,	O
if	O
any	O
exists	O
.	O
</s>
<s>
Since	O
beacon	O
frames	O
are	O
sent	O
using	O
the	O
mandatory	O
802.11	O
carrier	O
sense	O
multiple	O
access/collision	O
avoidance	O
(	O
CSMA/CA	O
)	O
algorithm	O
,	O
the	O
access	B-Device
point	I-Device
must	O
wait	O
if	O
a	O
client	O
device	O
is	O
sending	O
a	O
frame	O
when	O
the	O
beacon	O
is	O
to	O
be	O
sent	O
.	O
</s>
<s>
Upon	O
entering	O
power-save	O
mode	O
,	O
a	O
client	O
device	O
will	O
transmit	O
a	O
notification	O
to	O
the	O
access	B-Device
point	I-Device
,	O
so	O
that	O
the	O
access	B-Device
point	I-Device
will	O
know	O
how	O
to	O
handle	O
unicast	O
traffic	O
destined	O
for	O
the	O
client	O
device	O
.	O
</s>
<s>
In	O
the	O
present	O
standards	O
,	O
an	O
access	B-Device
point	I-Device
is	O
able	O
to	O
store	O
only	O
a	O
single	O
DTIM	O
period	O
.	O
</s>
<s>
A	O
network	O
manager	O
may	O
need	O
to	O
balance	O
the	O
conflicting	O
requirements	O
for	O
power	O
consumption	O
and	O
communication	O
throughput	O
when	O
in	O
power-save	O
mode	O
of	O
client	O
devices	O
in	O
different	O
wireless	O
networks	O
when	O
configuring	O
the	O
DTIM	O
period	O
of	O
an	O
access	B-Device
point	I-Device
.	O
</s>
<s>
In	O
the	O
future	O
,	O
an	O
access	B-Device
point	I-Device
that	O
can	O
serve	O
multiple	O
service	O
sets	O
(	O
multiple	O
SSIDs	O
)	O
may	O
have	O
a	O
separate	O
DTIM	O
period	O
for	O
each	O
service	O
set	O
.	O
</s>
