<s>
Ethernet	B-Protocol
in	I-Protocol
the	I-Protocol
first	I-Protocol
mile	I-Protocol
(	O
EFM	O
)	O
refers	O
to	O
using	O
one	O
of	O
the	O
Ethernet	O
family	O
of	O
computer	B-Architecture
network	I-Architecture
technologies	O
between	O
a	O
telecommunications	O
company	O
and	O
a	O
customer	O
's	O
premises	O
.	O
</s>
<s>
From	O
the	O
customer	O
's	O
point	O
of	O
view	O
,	O
it	O
is	O
their	O
first	O
mile	O
,	O
although	O
from	O
the	O
access	O
network	O
's	O
point	O
of	O
view	O
it	O
is	O
known	O
as	O
the	O
last	B-Protocol
mile	I-Protocol
.	O
</s>
<s>
Although	O
it	O
is	O
often	O
used	O
for	O
businesses	O
,	O
it	O
can	O
also	O
be	O
known	O
as	O
Ethernet	B-Protocol
to	I-Protocol
the	I-Protocol
home	I-Protocol
(	O
ETTH	B-Protocol
)	O
.	O
</s>
<s>
One	O
family	O
of	O
standards	O
known	O
as	O
Ethernet	O
passive	B-Architecture
optical	I-Architecture
network	I-Architecture
(	O
EPON	O
)	O
uses	O
a	O
passive	B-Architecture
optical	I-Architecture
network	I-Architecture
.	O
</s>
<s>
With	O
wide	O
,	O
metro	O
,	O
and	O
local	B-General_Concept
area	I-General_Concept
networks	I-General_Concept
using	O
various	O
forms	O
of	O
Ethernet	O
,	O
the	O
goal	O
was	O
to	O
eliminate	O
non-native	O
transport	O
such	O
as	O
Ethernet	O
over	O
Asynchronous	O
Transfer	O
Mode	O
(	O
ATM	O
)	O
from	O
access	O
networks	O
.	O
</s>
<s>
The	O
hope	O
was	O
to	O
combine	O
the	O
packet-based	O
nature	O
of	O
Ethernet	O
with	O
the	O
ability	O
of	O
digital	O
subscriber	B-Architecture
line	I-Architecture
(	O
DSL	O
)	O
technology	O
to	O
work	O
over	O
existing	O
telephone	O
access	O
wires	O
.	O
</s>
<s>
The	O
name	O
comes	O
from	O
local	B-Architecture
loop	I-Architecture
,	O
which	O
traditionally	O
describes	O
the	O
wires	O
from	O
a	O
telephone	O
company	O
office	O
to	O
a	O
subscriber	O
.	O
</s>
<s>
Another	O
effort	O
was	O
the	O
concept	O
promoted	O
by	O
Michael	O
Silverton	O
of	O
using	O
Ethernet	O
variants	O
that	O
used	O
fiber	B-Application
optic	I-Application
communication	I-Application
to	O
residential	O
as	O
well	O
as	O
business	O
customers	O
.	O
</s>
<s>
This	O
was	O
an	O
example	O
of	O
what	O
has	O
become	O
known	O
as	O
fiber	B-Architecture
to	I-Architecture
the	I-Architecture
home	I-Architecture
(	O
FTTH	B-Architecture
)	O
.	O
</s>
<s>
Some	O
early	O
products	O
around	O
the	O
year	O
2000	O
,	O
were	O
marketed	O
as	O
10BaseS	B-Protocol
by	O
Infineon	O
Technologies	O
,	O
although	O
they	O
did	O
not	O
technically	O
use	O
baseband	B-Algorithm
signalling	O
,	O
but	O
rather	O
passband	B-Algorithm
as	O
in	O
very-high-bit-rate	O
digital	O
subscriber	B-Architecture
line	I-Architecture
(	O
VDSL	O
)	O
technology	O
.	O
</s>
<s>
Long	B-Protocol
Reach	I-Protocol
Ethernet	I-Protocol
was	O
the	O
product	O
name	O
used	O
by	O
Cisco	O
Systems	O
starting	O
in	O
2001	O
.	O
</s>
<s>
In	O
October	O
2000	O
Howard	O
Frazier	O
issued	O
a	O
call	O
for	O
interest	O
on	O
"	O
Ethernet	B-Protocol
in	I-Protocol
the	I-Protocol
Last	I-Protocol
Mile	I-Protocol
"	O
.	O
</s>
<s>
At	O
the	O
November	O
2000	O
meeting	O
,	O
IEEE	O
802.3	O
created	O
the	O
"	O
Ethernet	B-Protocol
in	I-Protocol
the	I-Protocol
First	I-Protocol
Mile	I-Protocol
"	O
study	O
group	O
,	O
and	O
on	O
July	O
16	O
,	O
2001	O
the	O
802.3ah	B-Protocol
working	O
group	O
.	O
</s>
<s>
In	O
parallel	O
participating	O
vendors	O
formed	O
the	O
Ethernet	B-Protocol
in	I-Protocol
the	I-Protocol
First	I-Protocol
Mile	I-Protocol
Alliance	O
(	O
EFMA	O
)	O
in	O
December	O
2001	O
to	O
promote	O
Ethernet	O
subscriber	O
access	O
technology	O
and	O
support	O
the	O
IEEE	O
standard	O
efforts	O
.	O
</s>
<s>
In	O
2005	O
,	O
the	O
EFMA	O
was	O
absorbed	O
by	O
the	O
Metro	B-Protocol
Ethernet	I-Protocol
Forum	O
.	O
</s>
<s>
In	O
early	O
2006	O
,	O
work	O
began	O
on	O
an	O
even	O
higher-speed	O
10	O
gigabit/second	O
Ethernet	O
passive	B-Architecture
optical	I-Architecture
network	I-Architecture
(	O
10G-EPON	B-Protocol
)	O
standard	O
,	O
ratified	O
in	O
2009	O
as	O
IEEE	B-Protocol
802.3av	I-Protocol
.	O
</s>
<s>
The	O
major	O
goals	O
for	O
this	O
Task	O
Force	O
included	O
adding	O
support	O
for	O
PX30	O
,	O
PX40	O
,	O
PRX40	O
,	O
and	O
PR40	O
power	O
budget	O
classes	O
to	O
both	O
1G-EPON	O
and	O
10G-EPON	B-Protocol
.	O
</s>
<s>
In	O
November	O
2011	O
,	O
IEEE	O
802.3	O
began	O
work	O
on	O
EPON	B-Protocol
Protocol	I-Protocol
over	I-Protocol
Coax	I-Protocol
(	O
EPoC	O
)	O
.	O
</s>
<s>
On	O
June	O
4	O
,	O
2020	O
,	O
the	O
IEEE	O
approved	O
IEEE	O
802.3ca	O
which	O
allows	O
for	O
symmetric	O
or	O
asymmetric	O
operation	O
with	O
downstream	O
speeds	O
of	O
25	O
Gbit/s	O
or	O
50	O
Gbit/s	O
,	O
and	O
upstream	O
speeds	O
of	O
10	O
Gbit/s	O
,	O
25	O
Gbit/s	O
,	O
or	O
50	O
Gbit/s	O
over	O
passive	B-Architecture
optical	I-Architecture
networks	I-Architecture
.	O
</s>
<s>
EFM	O
defines	O
how	O
Ethernet	O
can	O
be	O
transmitted	O
over	O
new	O
media	O
types	O
using	O
new	O
Ethernet	B-Protocol
physical	I-Protocol
layer	I-Protocol
(	O
PHY	O
)	O
interfaces	O
:	O
</s>
<s>
Voice-grade	B-Protocol
copper	I-Protocol
.	O
</s>
<s>
Point-to-multipoint	B-General_Concept
(	O
P2MP	B-General_Concept
)	O
fiber	O
.	O
</s>
<s>
These	O
new	O
interfaces	O
are	O
known	O
under	O
the	O
collective	O
name	O
of	O
Ethernet	O
over	O
passive	B-Architecture
optical	I-Architecture
networks	I-Architecture
(	O
EPON	O
)	O
.	O
</s>
<s>
EFM	O
also	O
addresses	O
other	O
issues	O
,	O
required	O
for	O
mass	O
deployment	O
of	O
Ethernet	O
services	O
,	O
such	O
as	O
operations	O
,	O
administration	O
,	O
and	O
management	O
(	O
OA&M	B-Architecture
)	O
and	O
compatibility	O
with	O
existing	O
technologies	O
(	O
such	O
as	O
plain	O
old	O
telephone	O
service	O
spectral	O
compatibility	O
for	O
copper	O
twisted	O
pair	O
)	O
.	O
</s>
<s>
2BASE-TL	B-Protocol
--	O
defined	O
in	O
clauses	O
61	O
and	O
63	O
.	O
</s>
<s>
Full-duplex	O
long-reach	O
point-to-point	B-Architecture
link	I-Architecture
over	O
voice-grade	B-Protocol
copper	I-Protocol
wiring	O
.	O
</s>
<s>
2BASE-TL	B-Protocol
PHY	O
can	O
deliver	O
a	O
minimum	O
of	O
2	O
Mbit/s	O
and	O
a	O
maximum	O
of	O
5.69	O
Mbit/s	O
over	O
distances	O
of	O
up	O
to	O
2700	O
m	O
(	O
9,000	O
ft	O
)	O
,	O
using	O
ITU-T	O
G.991.2	O
(	O
G.SHDSL.bis	O
)	O
technology	O
over	O
a	O
single	O
copper	O
pair	O
.	O
</s>
<s>
Full-duplex	O
short-reach	O
point-to-point	B-Architecture
link	I-Architecture
over	O
voice-grade	B-Protocol
copper	I-Protocol
wiring	O
.	O
</s>
<s>
100BASE-LX10	O
defined	O
in	O
clause	O
58	O
,	O
providing	O
point-to-point	B-Architecture
100	O
Mbit/s	O
Ethernet	O
links	O
over	O
a	O
pair	O
of	O
single-mode	O
fibers	O
up	O
to	O
at	O
least	O
10km	O
.	O
</s>
<s>
100BASE-BX10	O
defined	O
in	O
clause	O
58	O
,	O
providing	O
point-to-point	B-Architecture
100	O
Mbit/s	O
Ethernet	O
links	O
over	O
an	O
individual	O
single-mode	O
fiber	O
up	O
to	O
at	O
least	O
10km	O
.	O
</s>
<s>
1000BASE-LX10	O
defined	O
in	O
clause	O
59	O
,	O
providing	O
point-to-point	B-Architecture
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
a	O
pair	O
of	O
single-mode	O
fibers	O
up	O
to	O
at	O
least	O
10km	O
.	O
</s>
<s>
1000BASE-BX10	O
defined	O
in	O
clause	O
59	O
,	O
providing	O
point-to-point	B-Architecture
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
an	O
individual	O
single-mode	O
fiber	O
up	O
to	O
at	O
least	O
10km	O
.	O
</s>
<s>
Fiber	B-Architecture
to	I-Architecture
the	I-Architecture
home	I-Architecture
can	O
use	O
a	O
passive	B-Architecture
optical	I-Architecture
network	I-Architecture
.	O
</s>
<s>
1000BASE-PX10	O
defined	O
in	O
Clause	O
60	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3ah-2004	O
)	O
,	O
providing	O
P2MP	B-General_Concept
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
PONs	O
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
10km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:16	O
.	O
</s>
<s>
1000BASE-PX20	O
defined	O
in	O
Clause	O
60	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3ah-2004	O
)	O
,	O
providing	O
P2MP	B-General_Concept
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
PONs	O
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:16	O
.	O
</s>
<s>
1000BASE-PX30	O
defined	O
in	O
Clause	O
60	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3bk-2013	O
)	O
,	O
providing	O
P2MP	B-General_Concept
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
PONs	O
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:32	O
.	O
</s>
<s>
1000BASE-PX40	O
defined	O
in	O
Clause	O
60	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3bk-2013	O
)	O
,	O
providing	O
P2MP	B-General_Concept
1000	O
Mbit/s	O
Ethernet	O
links	O
over	O
PONs	O
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:64	O
.	O
</s>
<s>
10GBASE-PR10	O
defined	O
in	O
Clause	O
91	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3av-2009	O
)	O
,	O
providing	O
P2MP	B-General_Concept
10	B-Protocol
Gbit/s	I-Protocol
Ethernet	I-Protocol
links	I-Protocol
over	I-Protocol
PONs	I-Protocol
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
10km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:16	O
.	O
</s>
<s>
10GBASE-PR20	O
defined	O
in	O
Clause	O
91	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3av-2009	O
)	O
,	O
providing	O
P2MP	B-General_Concept
10	B-Protocol
Gbit/s	I-Protocol
Ethernet	I-Protocol
links	I-Protocol
over	I-Protocol
PONs	I-Protocol
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:16	O
.	O
</s>
<s>
10GBASE-PR30	O
defined	O
in	O
Clause	O
91	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3av-2009	O
)	O
,	O
providing	O
P2MP	B-General_Concept
10	B-Protocol
Gbit/s	I-Protocol
Ethernet	I-Protocol
links	I-Protocol
over	I-Protocol
PONs	I-Protocol
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:32	O
.	O
</s>
<s>
10GBASE-PR40	O
defined	O
in	O
Clause	O
60	O
(	O
added	O
by	O
IEEE	O
Std	O
802.3bk-2013	O
)	O
,	O
providing	O
P2MP	B-General_Concept
10	B-Protocol
Gbit/s	I-Protocol
Ethernet	I-Protocol
links	I-Protocol
over	I-Protocol
PONs	I-Protocol
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:64	O
.	O
</s>
<s>
25GBASE	O
and	O
50GBASE	O
added	O
by	O
IEEE	O
Std	O
802.3ca-2020	O
,	O
providing	O
P2MP	B-General_Concept
25	O
Gbit/s	O
Ethernet	O
links	O
over	O
PONs	O
,	O
at	O
the	O
distance	O
of	O
at	O
least	O
20km	O
,	O
at	O
the	O
split	O
of	O
at	O
least	O
1:32	O
.	O
</s>
<s>
Additionally	O
clause	O
57	O
defines	O
link-level	O
OA&M	B-Architecture
,	O
including	O
discovery	O
,	O
link	O
monitoring	O
,	O
remote	O
fault	O
indication	O
,	O
loopbacks	O
,	O
and	O
variable	O
access	O
.	O
</s>
<s>
2BASE-TL	B-Protocol
is	O
an	O
IEEE	O
802.3-2008	O
Physical	O
Layer	O
(	O
PHY	O
)	O
specification	O
for	O
a	O
full-duplex	O
long-reach	O
point-to-point	B-Architecture
Ethernet	O
link	O
over	O
voice-grade	B-Protocol
copper	I-Protocol
wiring	O
.	O
</s>
<s>
Unlike	O
10/100/100	O
PHYs	O
,	O
providing	O
a	O
single	O
rate	O
of	O
10	O
,	O
100	O
,	O
or	O
1000Mbit/s	O
,	O
the	O
2BASE-TL	B-Protocol
link	O
rate	O
can	O
vary	O
,	O
depending	O
on	O
the	O
copper	O
media	O
characteristics	O
(	O
such	O
as	O
length	O
,	O
wire	O
diameter	O
or	O
gauge	O
,	O
number	O
of	O
pairs	O
if	O
the	O
link	O
is	O
aggregated	O
,	O
amount	O
of	O
crosstalk	O
between	O
the	O
pairs	O
,	O
etc	O
.	O
</s>
<s>
2BASE-TL	B-Protocol
PHYs	O
deliver	O
a	O
minimum	O
of	O
2	O
Mbit/s	O
over	O
distances	O
of	O
up	O
to	O
,	O
using	O
ITU-T	O
G.991.2	O
(	O
G.SHDSL.bis	O
)	O
technology	O
over	O
a	O
single	O
copper	O
pair	O
.	O
</s>
<s>
These	O
PHYs	O
may	O
also	O
support	O
an	O
optional	O
aggregation	O
or	O
bonding	O
of	O
multiple	O
copper	O
pairs	O
,	O
called	O
PME	B-Protocol
Aggregation	I-Protocol
Function	I-Protocol
(	O
PAF	O
)	O
.	O
</s>
<s>
The	O
throughput	O
of	O
a	O
2BASE-TL	B-Protocol
link	O
is	O
lower	O
than	O
the	O
link	O
's	O
bitrate	O
by	O
an	O
average	O
5%	O
,	O
due	O
to	O
64/65	O
-octet	O
encoding	O
and	O
PAF	O
overhead	O
;	O
both	O
factors	O
depend	O
on	O
packet	O
size	O
.	O
</s>
<s>
10PASS-TS	O
is	O
an	O
IEEE	O
802.3-2008	O
Physical	O
Layer	O
(	O
PHY	O
)	O
specification	O
for	O
a	O
full-duplex	O
short-reach	O
point-to-point	B-Architecture
Ethernet	O
link	O
over	O
voice-grade	B-Protocol
copper	I-Protocol
wiring	O
.	O
</s>
<s>
These	O
PHYs	O
may	O
also	O
support	O
an	O
optional	O
aggregation	O
or	O
bonding	O
of	O
multiple	O
copper	O
pairs	O
,	O
called	O
PME	B-Protocol
Aggregation	I-Protocol
Function	I-Protocol
(	O
PAF	O
)	O
.	O
</s>
<s>
Unlike	O
other	O
Ethernet	B-Protocol
physical	I-Protocol
layers	I-Protocol
that	O
provide	O
a	O
single	O
rate	O
such	O
as	O
10	O
,	O
100	O
,	O
or	O
1000	O
Mbit/s	O
,	O
the	O
10PASS-TS	O
link	O
rate	O
can	O
vary	O
,	O
similar	O
to	O
2BASE-TL	B-Protocol
,	O
depending	O
on	O
the	O
copper	O
channel	O
characteristics	O
,	O
such	O
as	O
length	O
,	O
wire	O
diameter	O
(	O
gauge	O
)	O
,	O
wiring	O
quality	O
,	O
the	O
number	O
of	O
pairs	O
if	O
the	O
link	O
is	O
aggregated	O
and	O
other	O
factors	O
.	O
</s>
<s>
VDSL	O
is	O
a	O
short	O
range	O
technology	O
designed	O
to	O
provide	O
broadband	O
over	O
distances	O
less	O
than	O
1km	O
of	O
voice-grade	B-Protocol
copper	I-Protocol
twisted	O
pair	O
line	O
,	O
but	O
connection	O
data	O
rates	O
deteriorate	O
quickly	O
as	O
the	O
line	O
distance	O
increases	O
.	O
</s>
<s>
This	O
has	O
led	O
to	O
VDSL	O
being	O
referred	O
to	O
as	O
a	O
"	O
fiber	B-Architecture
to	I-Architecture
the	I-Architecture
curb	I-Architecture
"	O
technology	O
,	O
because	O
it	O
requires	O
fiber	O
backhaul	B-General_Concept
to	O
connect	O
with	O
a	O
carrier	O
network	O
over	O
greater	O
distances	O
.	O
</s>
<s>
VDSL	O
Ethernet	B-Protocol
in	I-Protocol
the	I-Protocol
first	I-Protocol
mile	I-Protocol
services	O
using	O
may	O
be	O
a	O
useful	O
way	O
to	O
standardise	O
functionality	O
on	O
metro	B-Protocol
Ethernet	I-Protocol
networks	O
,	O
or	O
potentially	O
to	O
distribute	O
internet	O
access	O
services	O
over	O
voice-grade	O
wiring	O
in	O
multi-dwelling	O
unit	O
buildings	O
.	O
</s>
