<s>
The	O
Dynamic	B-Protocol
Delegation	I-Protocol
Discovery	I-Protocol
System	I-Protocol
(	O
DDDS	B-Protocol
)	O
is	O
an	O
algorithm	O
for	O
applying	O
string	O
transformation	O
rules	O
to	O
application-unique	O
strings	O
to	O
extract	O
specific	O
syntax	O
elements	O
.	O
</s>
<s>
It	O
is	O
used	O
for	O
finding	O
information	O
,	O
such	O
as	O
authoritative	O
domain	O
name	O
servers	O
,	O
for	O
Uniform	B-Protocol
Resource	I-Protocol
Identifiers	I-Protocol
and	O
Uniform	B-Protocol
Resource	I-Protocol
Names	I-Protocol
.	O
</s>
<s>
An	O
earlier	O
specification	O
applied	O
only	O
to	O
URNs	B-Protocol
,	O
and	O
was	O
called	O
the	O
Resolver	O
Discovery	O
Service	O
(	O
RDS	O
)	O
.	O
</s>
<s>
DDDS	B-Protocol
defines	O
a	O
mechanism	O
for	O
using	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
(	O
DNS	B-Protocol
)	O
as	O
the	O
database	O
for	O
arbitrary	O
identifier	O
schemes	O
.	O
</s>
<s>
The	O
primary	O
logical	O
DNS	B-Protocol
container	O
used	O
to	O
hold	O
DDDS	B-Protocol
information	O
is	O
the	O
NAPTR	B-Protocol
record	I-Protocol
.	O
</s>
<s>
DDDS	B-Protocol
is	O
defined	O
in	O
RFC	O
3401	O
,	O
RFC	O
3402	O
,	O
RFC	O
3403	O
,	O
RFC	O
3404	O
,	O
and	O
RFC	O
3405	O
.	O
</s>
<s>
The	O
Dynamic	B-Protocol
Delegation	I-Protocol
Discovery	I-Protocol
System	I-Protocol
is	O
used	O
to	O
implement	O
lazy	O
binding	O
of	O
strings	O
to	O
data	O
,	O
in	O
order	O
to	O
support	O
dynamically	O
configured	O
delegation	O
systems	O
.	O
</s>
<s>
The	O
DDDS	B-Protocol
functions	O
by	O
mapping	O
some	O
unique	O
string	O
to	O
data	O
stored	O
within	O
a	O
DDDS	B-Protocol
Database	O
by	O
iteratively	O
applying	O
string	O
transformation	O
rules	O
until	O
a	O
terminal	O
condition	O
is	O
reached	O
.	O
</s>
<s>
Telephone	O
Number	O
Mapping	O
(	O
ENUM	O
)	O
,	O
specified	O
in	O
RFC	O
6116	O
,	O
is	O
defined	O
as	O
a	O
DDDS	B-Protocol
application	O
to	O
resolve	O
telephone	O
numbers	O
into	O
DNS	B-Protocol
data	O
.	O
</s>
