<s>
Ethernet	B-Protocol
over	I-Protocol
PDH	I-Protocol
over	I-Protocol
SONET/SDH	I-Protocol
(	O
EoPoS	B-Protocol
)	O
is	O
one	O
of	O
many	O
techniques	O
that	O
provided	O
Ethernet	O
connectivity	O
over	O
non-Ethernet	O
networks	O
.	O
</s>
<s>
EoPoS	B-Protocol
is	O
a	O
standardized	O
method	O
for	O
transporting	O
native	O
Ethernet	O
frames	O
over	O
the	O
existing	O
telecommunications	O
optical	O
infrastructure	O
use	O
both	O
the	O
established	O
Plesiochronous	B-Protocol
Digital	I-Protocol
Hierarchy	I-Protocol
(	O
PDH	B-Protocol
)	O
and	O
Synchronous	B-Protocol
Digital	I-Protocol
Hierarchy	I-Protocol
(	O
SONET/SDH	B-Protocol
)	O
transport	O
technologies	O
.	O
</s>
<s>
EoPoS	B-Protocol
is	O
a	O
standardized	O
method	O
for	O
transporting	O
native	O
Ethernet	O
frames	O
over	O
a	O
SONET/SDH	B-Protocol
network	O
,	O
by	O
first	O
mapping	O
into	O
one	O
or	O
more	O
PDH	B-Protocol
tributaries	O
such	O
as	O
T1	B-Protocol
,	O
E1	O
,	O
or	O
DS3	O
.	O
</s>
<s>
The	O
tributaries	O
can	O
then	O
be	O
dropped	O
from	O
a	O
legacy	O
ADM	O
,	O
delivered	O
to	O
the	O
customer	O
premises	O
,	O
and	O
the	O
PDH	B-Protocol
links	O
resolved	O
back	O
to	O
an	O
Ethernet	O
connection	O
by	O
a	O
piece	O
of	O
equipment	O
supporting	O
EoPDH	B-Protocol
.	O
</s>
<s>
The	O
technologies	O
used	O
in	O
EoPoS	B-Protocol
include	O
GFP	B-Protocol
frame	O
encapsulation	B-Protocol
,	O
Ethernet	O
Mapping	O
,	O
Virtual	B-Protocol
Concatenation	I-Protocol
,	O
Link	B-Protocol
Capacity	I-Protocol
Adjustment	I-Protocol
Scheme	I-Protocol
,	O
and	O
Management	O
Messaging	O
(	O
)	O
.	O
</s>
<s>
Common	O
practices	O
in	O
EoPoS	B-Protocol
equipment	O
also	O
include	O
the	O
tagging	O
of	O
traffic	O
for	O
separation	O
into	O
virtual	O
networks	O
,	O
prioritization	O
of	O
user	O
traffic	O
.	O
</s>
<s>
By	O
first	O
mapping	O
into	O
one	O
or	O
more	O
PDH	B-Protocol
tributaries	O
such	O
as	O
T1	B-Protocol
,	O
E1	O
,	O
or	O
DS3	O
,	O
the	O
component	O
Ethernet	O
contained	O
in	O
separate	O
PDH	B-Protocol
signals	O
from	O
a	O
central	O
location	O
can	O
be	O
fanned	O
out	O
to	O
multiple	O
locations	O
.	O
</s>
<s>
EoPoS	B-Protocol
allows	O
transport	O
of	O
native	O
Ethernet	O
frames	O
over	O
a	O
SONET/SDH	B-Protocol
network	O
.	O
</s>
<s>
Then	O
the	O
component	O
PDH	B-Protocol
can	O
then	O
be	O
separately	O
dropped	O
using	O
a	O
legacy	O
add-drop	O
multiplexer	O
.	O
</s>
<s>
Finally	O
,	O
the	O
PDH	B-Protocol
links	O
are	O
resolved	O
back	O
to	O
Ethernet	O
connections	O
by	O
equipment	O
supporting	O
EoPDH	B-Protocol
.	O
</s>
<s>
For	O
proper	O
operation	O
each	O
of	O
the	O
virtual	B-General_Concept
local	I-General_Concept
area	I-General_Concept
network	I-General_Concept
must	O
be	O
individually	O
tagged	O
using	O
IEEE	O
802.1Q	O
for	O
example	O
.	O
</s>
