<s>
Switched	B-Protocol
Multi-megabit	I-Protocol
Data	I-Protocol
Service	I-Protocol
(	O
SMDS	B-Protocol
)	O
was	O
a	O
connectionless	B-Protocol
service	O
used	O
to	O
connect	O
LANs	B-General_Concept
,	O
MANs	O
and	O
WANs	O
to	O
exchange	O
data	O
,	O
in	O
early	O
1990s	O
.	O
</s>
<s>
In	O
Europe	O
,	O
the	O
service	O
was	O
known	O
as	O
Connectionless	B-Protocol
Broadband	I-Protocol
Data	I-Protocol
Service	I-Protocol
(	O
CBDS	O
)	O
.	O
</s>
<s>
SMDS	B-Protocol
was	O
specified	O
by	O
Bellcore	O
,	O
and	O
was	O
based	O
on	O
the	O
IEEE	O
802.6	O
metropolitan	O
area	O
network	O
(	O
MAN	O
)	O
standard	O
,	O
as	O
implemented	O
by	O
Bellcore	O
,	O
and	O
used	O
cell	B-Protocol
relay	I-Protocol
transport	O
,	O
Distributed	B-Protocol
Queue	I-Protocol
Dual	I-Protocol
Bus	I-Protocol
layer-2	O
switching	O
arbitrator	O
,	O
and	O
standard	O
SONET	B-Protocol
or	O
G.703	O
as	O
access	O
interfaces	O
.	O
</s>
<s>
SMDS	B-Protocol
was	O
developed	O
by	O
Bellcore	O
as	O
an	O
interim	O
service	O
until	O
Asynchronous	O
Transfer	O
Mode	O
matured	O
.	O
</s>
<s>
SMDS	B-Protocol
was	O
notable	O
for	O
its	O
initial	O
introduction	O
of	O
the	O
53-byte	O
cell	O
and	O
cell	B-Protocol
switching	I-Protocol
approaches	O
,	O
as	O
well	O
as	O
the	O
method	O
of	O
inserting	O
53-byte	O
cells	O
onto	O
G.703	O
and	O
SONET	B-Protocol
.	O
</s>
<s>
In	O
the	O
mid-1990s	O
,	O
SMDS	B-Protocol
was	O
replaced	O
,	O
largely	O
by	O
Frame	B-Protocol
Relay	I-Protocol
.	O
</s>
