<s>
In	O
computer	B-Architecture
networking	I-Architecture
and	O
telecommunications	O
,	O
a	O
pseudowire	B-Protocol
(	O
or	O
pseudo-wire	B-Protocol
)	O
is	O
an	O
emulation	O
of	O
a	O
point-to-point	B-Architecture
connection	I-Architecture
over	O
a	O
packet-switched	B-Protocol
network	I-Protocol
(	O
PSN	O
)	O
.	O
</s>
<s>
The	O
pseudowire	B-Protocol
emulates	O
the	O
operation	O
of	O
a	O
"	O
transparent	O
wire	O
"	O
carrying	O
the	O
service	O
,	O
but	O
it	O
is	O
realized	O
that	O
this	O
emulation	O
will	O
rarely	O
be	O
perfect	O
.	O
</s>
<s>
The	O
service	O
being	O
carried	O
over	O
the	O
"	O
wire	O
"	O
may	O
be	O
Asynchronous	O
Transfer	O
Mode	O
(	O
ATM	O
)	O
,	O
Frame	B-Protocol
Relay	I-Protocol
,	O
Ethernet	O
or	O
time-division	B-Protocol
multiplexing	I-Protocol
(	O
TDM	O
)	O
while	O
the	O
packet	B-Protocol
network	I-Protocol
may	O
be	O
Multi-protocol	B-Protocol
Label	I-Protocol
Switching	I-Protocol
(	O
MPLS	B-Protocol
)	O
,	O
Internet	B-Protocol
Protocol	I-Protocol
(	O
IPv4	B-Protocol
or	O
IPv6	B-Protocol
)	O
,	O
or	O
Layer	B-Protocol
2	I-Protocol
Tunneling	I-Protocol
Protocol	I-Protocol
Version	I-Protocol
3	I-Protocol
(	O
L2TPv3	B-Protocol
)	O
.	O
</s>
<s>
The	O
first	O
pseudowire	B-Protocol
specifications	O
were	O
the	O
Martini	O
draft	O
for	O
ATM	O
pseudowires	B-Protocol
,	O
and	O
the	O
TDMoIP	B-Protocol
draft	O
for	O
transport	O
of	O
E1/T1	O
over	O
IP	O
.	O
</s>
<s>
In	O
2001	O
,	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
(	O
IETF	O
)	O
set	O
up	O
the	O
PWE3	O
working	O
group	O
,	O
which	O
was	O
chartered	O
to	O
develop	O
an	O
architecture	O
for	O
service	O
provider	O
edge-to-edge	O
pseudowires	B-Protocol
,	O
and	O
service-specific	O
documents	O
detailing	O
the	O
encapsulation	B-Protocol
techniques	O
.	O
</s>
<s>
Other	O
standardization	O
forums	O
,	O
including	O
the	O
International	O
Telecommunication	O
Union	O
(	O
ITU	O
)	O
and	O
the	O
MFA	O
Forum	O
,	O
are	O
also	O
active	O
in	O
producing	O
standards	O
and	O
implementation	O
agreements	O
for	O
pseudowires	B-Protocol
.	O
</s>
<s>
Starting	O
from	O
2006	O
,	O
telecom	O
operators	O
like	O
BellSouth	O
,	O
Supercomm	O
,	O
AT&T	O
,	O
and	O
Verizon	O
began	O
to	O
invest	O
more	O
into	O
pseudowire	B-Protocol
technology	O
,	O
pointing	O
out	O
its	O
advantages	O
to	O
Ethernet	O
in	O
particular	O
.	O
</s>
<s>
Pseudowires	B-Protocol
tie	O
services	O
together	O
across	O
multiple	O
transport	O
technologies	O
,	O
including	O
Ethernet	B-Protocol
over	I-Protocol
SONET	I-Protocol
,	O
WDM	O
,	O
GPON	B-Architecture
,	O
DSL	O
,	O
and	O
WiMax	O
.	O
</s>
<s>
In	O
2017	O
Cisco	O
published	O
a	O
comprehensive	O
document	O
explaining	O
the	O
concept	O
,	O
troubleshooting	O
,	O
and	O
configuration	O
details	O
for	O
all	O
Cisco	O
equipment	O
pieces	O
,	O
which	O
supported	O
pseudowire	B-Protocol
.	O
</s>
<s>
Today	O
,	O
the	O
service	O
is	O
provided	O
by	O
a	O
number	O
of	O
telecommunication	O
companies	O
like	O
Axerra	O
Networks	O
,	O
MCI	B-Application
Inc	I-Application
,	O
or	O
by	O
Infrastructure	B-General_Concept
as	I-General_Concept
a	I-General_Concept
service	I-General_Concept
providers	O
like	O
Voxility	O
.	O
</s>
<s>
There	O
are	O
now	O
many	O
pseudowire	B-Protocol
standards	O
,	O
the	O
most	O
important	O
of	O
which	O
are	O
IETF	O
RFCs	O
as	O
well	O
as	O
ITU-T	O
Recommendations	O
:	O
</s>
