<s>
FlexE	B-Protocol
,	O
short	O
for	O
Flexible	B-Protocol
Ethernet	I-Protocol
,	O
is	O
a	O
communications	O
protocol	O
published	O
by	O
the	O
Optical	O
Internetworking	O
Forum	O
(	O
OIF	O
)	O
.	O
</s>
<s>
The	O
OIF	O
published	O
the	O
FlexE	B-Protocol
Interoperability	O
Agreement	O
(	O
IA	O
)	O
in	O
2016	O
.	O
</s>
<s>
FlexE	B-Protocol
enables	O
equipment	O
to	O
support	O
new	O
Ethernet	O
connection	O
types	O
.	O
</s>
<s>
FlexE	B-Protocol
allows	O
data	B-Operating_System
center	I-Operating_System
providers	O
to	O
utilize	O
optical	B-Protocol
transport	I-Protocol
network	I-Protocol
bandwidth	O
in	O
more	O
flexible	O
ways	O
.	O
</s>
<s>
FlexE	B-Protocol
supports	O
the	O
bonding	B-Architecture
of	O
multiple	O
links	O
,	O
which	O
supports	O
creating	O
larger	O
links	O
out	O
of	O
multiple	O
slower	O
links	O
in	O
a	O
more	O
efficient	O
way	O
than	O
the	O
traditional	O
link	B-Architecture
aggregation	I-Architecture
.	O
</s>
<s>
FlexE	B-Protocol
also	O
supports	O
the	O
sub-rating	O
of	O
links	O
,	O
which	O
allows	O
an	O
operator	O
to	O
only	O
use	O
a	O
portion	O
of	O
a	O
link	O
.	O
</s>
<s>
FlexE	B-Protocol
also	O
supports	O
the	O
channelization	O
of	O
links	O
,	O
which	O
allows	O
one	O
link	O
to	O
carry	O
several	O
lower-speed	O
or	O
sub-rated	O
links	O
from	O
different	O
sources	O
.	O
</s>
<s>
FlexE	B-Protocol
reuses	O
many	O
mechanisms	O
from	O
Ethernet	O
.	O
</s>
<s>
Much	O
of	O
the	O
FlexE	B-Protocol
's	O
functionality	O
is	O
achieved	O
by	O
adding	O
a	O
time-division	B-Protocol
multiplexing	I-Protocol
calendar	O
that	O
interacts	O
with	O
the	O
existing	O
Ethernet	O
64b66b	O
mechanism	O
,	O
allowing	O
bandwidth	O
to	O
be	O
allocated	O
with	O
5Gbit/s	O
granularity	O
.	O
</s>
<s>
FlexE	B-Protocol
is	O
defined	O
to	O
make	O
use	O
of	O
standards-defined	O
physical	O
lanes	O
,	O
namely	O
the	O
various	O
forms	O
of	O
25Gbit/s	O
Ethernet	O
lanes	O
.	O
</s>
<s>
FlexE	B-Protocol
can	O
utilize	O
the	O
entire	O
aggregated	O
link	O
,	O
creating	O
an	O
alternative	O
to	O
traditional	O
Link	B-Architecture
Aggregation	I-Architecture
(	O
LAG	O
)	O
solutions	O
,	O
which	O
use	O
70	O
–	O
80%	O
of	O
a	O
link	O
.	O
</s>
<s>
FlexE	B-Protocol
has	O
deterministic	O
performance	O
,	O
whereas	O
IEEE	O
802.3ad-based	O
or	O
the	O
later	O
802.1-based	O
LAG	O
does	O
not	O
.	O
</s>
<s>
FlexE	B-Protocol
has	O
low	O
added	O
latency	O
as	O
compared	O
to	O
regular	O
Ethernet	O
.	O
</s>
<s>
The	O
multiplexing	O
is	O
accomplished	O
using	O
time-division	B-Protocol
multiplexing	I-Protocol
instead	O
of	O
packet	O
buffers	O
.	O
</s>
<s>
FlexE	B-Protocol
is	O
backwards	O
compatible	O
with	O
the	O
existing	O
optical	B-Protocol
transport	I-Protocol
network	I-Protocol
(	O
OTN	O
)	O
infrastructure	O
.	O
</s>
<s>
A	O
FlexE	B-Protocol
compatible	O
interface	O
can	O
be	O
connected	O
to	O
a	O
piece	O
of	O
transport	O
gear	O
that	O
is	O
not	O
aware	O
of	O
FlexE	B-Protocol
.	O
</s>
<s>
When	O
using	O
it	O
in	O
this	O
manner	O
,	O
FlexE	B-Protocol
traffic	O
appears	O
to	O
the	O
transport	O
gear	O
as	O
if	O
it	O
was	O
ordinary	O
Ethernet	O
traffic	O
.	O
</s>
<s>
FlexE	B-Protocol
has	O
a	O
set	O
of	O
features	O
to	O
support	O
its	O
use	O
in	O
transport	O
networks	O
.	O
</s>
<s>
An	O
example	O
of	O
this	O
is	O
that	O
FlexE	B-Protocol
supports	O
two	O
copies	O
of	O
the	O
calendar	O
,	O
which	O
can	O
be	O
switched	O
between	O
.	O
</s>
<s>
The	O
optional	O
use	O
of	O
FlexE-aware	O
OTN	O
equipment	O
provides	O
additional	O
functionality	O
such	O
as	O
matching	O
client	O
and	O
line	O
rates	O
.	O
</s>
<s>
This	O
bandwidth	O
can	O
be	O
used	O
more	O
precisely	O
by	O
having	O
the	O
FlexE-aware	O
MAC	O
produce	O
the	O
right	O
amount	O
of	O
traffic	O
at	O
the	O
source	O
.	O
</s>
<s>
On	O
December	O
7	O
,	O
2016	O
,	O
the	O
OIF	O
announced	O
the	O
start	O
of	O
a	O
FlexE	B-Protocol
2.0	O
project	O
.	O
</s>
<s>
FlexE	B-Protocol
2.0	O
adds	O
management	O
detail	O
,	O
provides	O
a	O
way	O
to	O
scale	O
the	O
calendar	O
slot	O
bandwidth	O
,	O
adds	O
a	O
skew	O
management	O
option	O
,	O
and	O
supports	O
the	O
transport	O
of	O
time	O
or	O
frequency	O
.	O
</s>
<s>
The	O
OIF	O
task	O
group	O
that	O
developed	O
FlexE	B-Protocol
has	O
active	O
liaison	O
relationships	O
with	O
the	O
IEEE	O
802.3	O
working	O
group	O
and	O
the	O
International	O
Telecommunication	O
Union	O
study	O
group	O
15	O
.	O
</s>
<s>
A	O
FlexE	B-Protocol
compliant	O
implementation	O
was	O
demonstrated	O
in	O
the	O
OIF	O
booth	O
at	O
the	O
Optical	O
Fiber	O
Conference	O
in	O
2017	O
.	O
</s>
<s>
A	O
more	O
elaborate	O
demonstration	O
was	O
conducted	O
together	O
with	O
the	O
Ethernet	B-Protocol
Alliance	I-Protocol
at	O
OFC	O
in	O
2018	O
.	O
</s>
