<s>
A	O
frame	O
is	O
a	O
digital	O
data	O
transmission	O
unit	O
in	O
computer	B-Architecture
networking	I-Architecture
and	O
telecommunication	O
.	O
</s>
<s>
In	O
packet	B-Protocol
switched	I-Protocol
systems	O
,	O
a	O
frame	O
is	O
a	O
simple	O
container	O
for	O
a	O
single	O
network	B-Protocol
packet	I-Protocol
.	O
</s>
<s>
In	O
other	O
telecommunications	O
systems	O
,	O
a	O
frame	O
is	O
a	O
repeating	O
structure	O
supporting	O
time-division	B-Protocol
multiplexing	I-Protocol
.	O
</s>
<s>
In	O
the	O
OSI	O
model	O
of	O
computer	B-Architecture
networking	I-Architecture
,	O
a	O
frame	O
is	O
the	O
protocol	B-Protocol
data	I-Protocol
unit	I-Protocol
at	O
the	O
data	B-Protocol
link	I-Protocol
layer	I-Protocol
.	O
</s>
<s>
Frames	O
are	O
the	O
result	O
of	O
the	O
final	O
layer	O
of	O
encapsulation	B-Protocol
before	O
the	O
data	O
is	O
transmitted	O
over	O
the	O
physical	O
layer	O
.	O
</s>
<s>
A	O
frame	O
is	O
"	O
the	O
unit	O
of	O
transmission	O
in	O
a	O
link	O
layer	O
protocol	O
,	O
and	O
consists	O
of	O
a	O
link	O
layer	O
header	O
followed	O
by	O
a	O
packet.	O
"	O
</s>
<s>
Each	O
frame	O
is	O
separated	O
from	O
the	O
next	O
by	O
an	O
interframe	B-Protocol
gap	I-Protocol
.	O
</s>
<s>
A	O
frame	O
is	O
a	O
series	O
of	O
bits	O
generally	O
composed	O
of	O
frame	O
synchronization	O
bits	O
,	O
the	O
packet	B-Protocol
payload	O
,	O
and	O
a	O
frame	B-Protocol
check	I-Protocol
sequence	I-Protocol
.	O
</s>
<s>
Examples	O
are	O
Ethernet	B-Protocol
frames	I-Protocol
,	O
Point-to-Point	B-Protocol
Protocol	I-Protocol
(	O
PPP	O
)	O
frames	O
,	O
Fibre	B-Architecture
Channel	I-Architecture
frames	I-Architecture
,	O
and	O
V.42	O
modem	O
frames	O
.	O
</s>
<s>
For	O
example	O
,	O
when	O
using	O
Point-to-Point	B-Protocol
Protocol	I-Protocol
(	O
PPP	O
)	O
over	O
asynchronous	O
serial	O
communication	O
,	O
the	O
eight	O
bits	O
of	O
each	O
individual	O
byte	O
are	O
framed	O
by	O
start	O
and	O
stop	O
bits	O
,	O
the	O
payload	O
data	O
bytes	O
in	O
a	O
network	B-Protocol
packet	I-Protocol
are	O
framed	O
by	O
the	O
header	O
and	O
footer	O
,	O
and	O
several	O
packets	B-Protocol
can	O
be	O
framed	O
with	O
frame	O
boundary	O
octets	O
.	O
</s>
<s>
In	O
telecommunications	O
,	O
specifically	O
in	O
time-division	B-Protocol
multiplex	I-Protocol
(	O
TDM	O
)	O
and	O
time-division	B-Protocol
multiple	O
access	O
(	O
TDMA	O
)	O
variants	O
,	O
a	O
frame	O
is	O
a	O
cyclically	O
repeated	O
data	O
block	O
that	O
consists	O
of	O
a	O
fixed	O
number	O
of	O
time	O
slots	O
,	O
one	O
for	O
each	O
logical	O
TDM	O
channel	O
or	O
TDMA	O
transmitter	O
.	O
</s>
<s>
TDM	O
application	O
examples	O
are	O
SONET/SDH	B-Protocol
and	O
the	O
ISDN	B-Protocol
circuit-switched	O
B-channel	O
,	O
while	O
TDMA	O
examples	O
are	O
Circuit	O
Switched	O
Data	O
used	O
in	O
early	O
cellular	O
voice	O
services	O
.	O
</s>
<s>
The	O
frame	O
is	O
also	O
an	O
entity	O
for	O
time-division	B-Protocol
duplex	O
,	O
where	O
the	O
mobile	O
terminal	O
may	O
transmit	O
during	O
some	O
time	O
slots	O
and	O
receive	O
during	O
others	O
.	O
</s>
