<s>
In	O
computer	B-Architecture
networking	I-Architecture
,	O
out-of-band	O
data	O
is	O
the	O
data	O
transferred	O
through	O
a	O
stream	O
that	O
is	O
independent	O
from	O
the	O
main	O
in-band	O
data	O
stream	O
.	O
</s>
<s>
Consider	O
a	O
networking	O
application	O
that	O
tunnels	B-Protocol
data	O
from	O
a	O
remote	O
data	O
source	O
to	O
a	O
remote	O
destination	O
.	O
</s>
<s>
The	O
most	O
commonly	O
used	O
protocol	O
containing	O
an	O
out-of-band	O
data	O
mechanism	O
is	O
the	O
Internet	O
's	O
Transmission	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
Unfortunately	O
,	O
a	O
long-existing	O
discrepancy	O
between	O
and	O
limits	O
the	O
usability	O
of	O
this	O
feature	O
of	O
TCP	O
;	O
nonetheless	O
,	O
it	O
is	O
heavily	O
used	O
by	O
certain	O
standard	O
application	O
protocols	O
,	O
notably	O
the	O
Telnet	B-Protocol
protocol	O
.	O
</s>
<s>
A	O
process	O
or	O
process	O
group	O
can	O
be	O
configured	O
to	O
receive	O
SIGURG	B-General_Concept
signals	O
when	O
out-of-band	O
data	O
is	O
available	O
for	O
reading	O
on	O
a	O
socket	B-Protocol
,	O
by	O
using	O
the	O
F_SETOWN	O
command	O
of	O
the	O
fcntl( )	O
system	O
call	O
.	O
</s>
<s>
This	O
is	O
a	O
form	O
of	O
asynchronous	B-Architecture
I/O	I-Architecture
.	O
</s>
<s>
The	O
Serial	O
Advanced	O
Technology	O
Attachment	O
(	O
SATA	O
)	O
protocol	O
commonly	O
used	O
to	O
connect	O
disk	B-Device
drives	I-Device
to	O
computers	O
implements	O
an	O
out-of-band	O
data	O
protocol	O
.	O
</s>
