<s>
Service	B-Language
Modeling	I-Language
Language	I-Language
(	O
SML	O
)	O
and	O
Service	B-Language
Modeling	I-Language
Language	I-Language
Interchange	O
Format	O
(	O
SML-IF	O
)	O
are	O
a	O
pair	O
of	O
XML-based	O
specifications	B-Application
created	O
by	O
leading	O
information	B-General_Concept
technology	I-General_Concept
companies	O
that	O
define	O
a	O
set	O
of	O
XML	B-Protocol
instance	O
document	O
extensions	O
for	O
expressing	O
links	O
between	O
elements	O
,	O
a	O
set	O
of	O
XML	B-Protocol
Schema	O
extensions	O
for	O
constraining	O
those	O
links	O
,	O
and	O
a	O
way	O
to	O
associate	O
Schematron	B-Language
rules	O
with	O
global	O
element	O
declarations	O
,	O
global	O
complex	O
type	O
definitions	O
,	O
and/or	O
model	O
documents	O
.	O
</s>
<s>
The	O
SML	O
specification	B-Application
defines	O
model	O
concepts	O
,	O
and	O
the	O
SML-IF	O
specification	B-Application
describes	O
a	O
packaging	O
format	O
for	O
exchanging	O
SML-based	O
models	O
.	O
</s>
<s>
SML	O
and	O
SML-IF	O
were	O
standardized	O
in	O
a	O
W3C	O
working	O
group	O
chartered	O
to	O
produce	O
W3C	O
Recommendations	O
for	O
the	O
Service	B-Language
Modeling	I-Language
Language	I-Language
by	O
refining	O
the	O
“	O
Service	B-Language
Modeling	I-Language
Language	I-Language
”	O
(	O
SML	O
)	O
Member	O
Submission	O
,	O
addressing	O
implementation	O
experience	O
and	O
feedback	O
on	O
the	O
specifications	B-Application
.	O
</s>
<s>
In	O
the	O
market	O
and	O
in	O
applying	O
by	O
vendors	O
,	O
SML	O
is	O
seen	O
as	O
a	O
successor/replacement	O
for	O
earlier	O
developed	O
standards	O
like	O
DCML	B-Language
and	O
Microsoft	O
's	O
(	O
in	O
hindsight	O
)	O
proprietary	O
System	O
Definition	O
Model	O
or	O
SDM	O
.	O
</s>
<s>
See	O
for	O
a	O
historically	O
helpful	O
relation	O
between	O
SDM	O
and	O
DCML	B-Language
,	O
and	O
for	O
the	O
joint	O
pressrelease	O
announcing	O
SML	O
.	O
</s>
<s>
The	O
Service	B-Language
Modeling	I-Language
Language	I-Language
(	O
SML	O
)	O
is	O
a	O
language	O
for	O
building	O
a	O
rich	O
set	O
of	O
constructs	O
for	O
creating	O
and	O
constraining	O
models	O
of	O
complex	O
IT	O
services	O
and	O
systems	O
.	O
</s>
<s>
An	O
SML	O
model	O
is	O
a	O
set	O
of	O
interrelated	O
XML	B-Protocol
documents	I-Protocol
.	O
</s>
<s>
XML	B-Protocol
Schema	O
documents	O
constrain	O
the	O
structure	O
and	O
content	O
of	O
the	O
XML	B-Protocol
instance	O
documents	O
in	O
a	O
model	O
.	O
</s>
<s>
SML	O
uses	O
XML	B-Protocol
Schema	O
1.0	O
,	O
but	O
allows	O
later	O
versions	O
as	O
well	O
.	O
</s>
<s>
SML	O
also	O
defines	O
a	O
set	O
of	O
extensions	O
to	O
XML	B-Protocol
Schema	O
to	O
constrain	O
references	O
,	O
and	O
identity	O
constraints	O
(	O
key	O
,	O
unique	O
,	O
...	O
)	O
that	O
apply	O
to	O
sets	O
of	O
documents	O
.	O
</s>
<s>
SML	O
uses	O
Schematron	B-Language
and	O
XPath	B-Language
1.0	I-Language
for	O
rules	O
,	O
but	O
allows	O
later	O
versions	O
as	O
well	O
.	O
</s>
<s>
This	O
involves	O
checking	O
whether	O
all	O
model	O
documents	O
satisfy	O
the	O
XML	B-Protocol
Schema	O
and	O
rule	O
document	O
constraints	O
.	O
</s>
<s>
Models	O
drive	O
modularity	B-Architecture
,	O
Re-use	O
,	O
and	O
standardization	O
.	O
</s>
