<s>
Optical	B-Protocol
Carrier	I-Protocol
transmission	I-Protocol
rates	I-Protocol
are	O
a	O
standardized	O
set	O
of	O
specifications	O
of	O
transmission	O
bandwidth	O
for	O
digital	O
signals	O
that	O
can	O
be	O
carried	O
on	O
Synchronous	B-Protocol
Optical	I-Protocol
Networking	I-Protocol
(	O
SONET	B-Protocol
)	O
fiber	B-Architecture
optic	I-Architecture
networks	O
.	O
</s>
<s>
Thus	O
,	O
the	O
speed	O
of	O
optical-carrier-classified	O
lines	O
labeled	O
as	O
OC-n	B-Protocol
is	O
n	O
×	O
51.84Mbit/s	O
.	O
</s>
<s>
Optical	B-Protocol
Carrier	I-Protocol
classifications	O
are	O
based	O
on	O
the	O
abbreviation	O
OC	O
followed	O
by	O
a	O
number	O
specifying	O
a	O
multiple	O
of	O
51.84Mbit/s	O
:	O
n	O
×	O
51.84Mbit/s	O
=>	O
OC-n	B-Protocol
.	O
For	O
example	O
,	O
an	O
OC-3	O
transmission	O
medium	O
has	O
3	O
times	O
the	O
transmission	O
capacity	O
of	O
OC-1	O
.	O
</s>
<s>
OC-1	O
is	O
a	O
SONET	B-Protocol
line	O
with	O
transmission	O
speeds	O
of	O
up	O
to	O
51.84Mbit/s	O
(	O
payload	O
:	O
50.112Mbit/s	O
;	O
overhead	O
:	O
1.728Mbit/s	O
)	O
using	O
optical	B-Architecture
fiber	I-Architecture
.	O
</s>
<s>
OC-3	O
is	O
a	O
network	O
line	O
with	O
transmission	O
data	O
rate	O
of	O
up	O
to	O
155.52Mbit/s	O
(	O
payload	O
:	O
148.608Mbit/s	O
;	O
overhead	O
:	O
6.912Mbit/s	O
,	O
including	O
path	O
overhead	O
)	O
using	O
fiber	B-Architecture
optics	I-Architecture
.	O
</s>
<s>
Depending	O
on	O
the	O
system	O
OC-3	O
is	O
also	O
known	O
as	O
STS-3	O
(	O
electrical	O
level	O
)	O
and	O
STM-1	B-Protocol
(	O
SDH	B-Protocol
)	O
.	O
</s>
<s>
This	O
connection	O
speed	O
is	O
also	O
often	O
used	O
by	O
mid-sized	O
(	O
below	O
Tier	B-Architecture
2	I-Architecture
)	O
internet	O
customers	O
,	O
such	O
as	O
web	O
hosting	O
companies	O
or	O
smaller	O
ISPs	O
buying	O
service	O
from	O
larger	O
ones	O
.	O
</s>
<s>
Interconnections	O
between	O
large	O
ISPs	O
for	O
purposes	O
of	O
peering	B-Protocol
or	O
transit	B-Application
are	O
quite	O
common	O
.	O
</s>
<s>
On	O
October	O
23	O
,	O
2008	O
,	O
AT&T	O
announced	O
the	O
completion	O
of	O
upgrades	O
to	O
OC-768	O
on	O
80,000	O
fiber-optic	B-Architecture
wavelength	O
miles	O
of	O
their	O
IP/MPLS	B-Protocol
backbone	B-General_Concept
network	I-General_Concept
.	O
</s>
<s>
OC-768	O
SONET	B-Protocol
interfaces	O
have	O
been	O
available	O
with	O
short-reach	O
optical	O
interfaces	O
from	O
Cisco	O
since	O
2006	O
.	O
</s>
<s>
Infinera	O
made	O
a	O
field	O
trial	O
demonstration	O
data	O
transmission	O
on	O
a	O
live	O
production	O
network	O
involving	O
the	O
service	O
transmission	O
of	O
a	O
40Gbit/s	O
OC-768/STM	O
-256	O
service	O
over	O
a	O
1,969	O
km	O
terrestrial	O
network	O
spanning	O
Europe	O
and	O
the	O
U.S.	O
</s>
