service
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... The purpose of this document is to define a new, straightforward
Dynamic Delegation Discovery Service (DDDS) [7] application to allow
...
... mapping of domain names to URIs for particular application services
and protocols. This allows the "lookup" of particular services ...
... application services
and protocols. This allows the "lookup" of particular services
available for given domains, for example.
...
...
S-NAPTR provides for application service location that does not rely
on rigid domain naming conventions. It is deemed "straightforward"
...
... NAPTR RRs for example.com shown below, "WP" is the
imagined application service tag for "white pages", and "EM" is the
application service tag ...
... application service tag for "white pages", and "EM" is the
application service tag for an imagined "Extensible Messaging"
application service.
...
... application service tag for an imagined "Extensible Messaging"
application service.
example.com.
...
... IN NAPTR 100 20 "s" "WP:ldap" ( ; service
"" ; regexp
_ldap._tcp.myldap.example.com. ; replacement
...
... IN NAPTR 200 10 "u" "EM:protA" ( ; service
"!.*!prota://someisp.example.com!" ; regexp
"" ; replacement
...
... fully qualified domain name (FQDN)
for which an authoritative server for a particular service is sought.
...
... rule is the Application Unique String, the FQDN for which the
authoritative server for a particular service is sought.
...
... URI that should be resolved in order to obtain access to the
described service.
Consistent with the DDDS algorithm ...
... Service Parameters ...
...
Service Parameters for this Application take the form of a string of
characters that follow this ABNF [1 ...
... app-service] *(":" app-protocol)]
app-service = experimental-service / iana-registered-service
...
... app-service = experimental-service / iana-registered-service
app-protocol = experimental-protocol ...
... experimental-protocol / iana-registered-protocol
experimental-service = "x-" 1*30ALPHANUMSYM
experimental-protocol = "x-" 1*30ALPHANUMSYM
...
... experimental-protocol = "x-" 1*30ALPHANUMSYM
iana-registered-service = ALPHA *31ALPHANUMSYM
iana-registered-protocol ...
... ; characters and must start with an alphabetic character.
; The service-parms are considered case-insensitive.
...
... case-insensitive.
Thus, the Service Parameters may consist of an empty string, just an
app-service, or an app-service ...
... Thus, the Service Parameters may consist of an empty string, just an
app-service, or an app-service with one or more app-protocol
...
... Service Parameters may consist of an empty string, just an
app-service, or an app-service with one or more app-protocol
specifications separated by the ":" symbol.
...
... database requires each
DDDS application to define the syntax of allowable service strings.
The syntax here is expanded to allow the characters that are valid in
...
... 8]). Since "+" (the separator used in the
RFC3404prop service parameter string) is an allowed character for URI
scheme names, ":" is chosen as the separator here.
...
... Application Services ...
... The "app-service" must be an IANA-registered service; see Section 5
for instructions on registering new application service tags.
...
... IANA-registered service; see Section 5
for instructions on registering new application service tags.
...
... IANA, but
provides the basis upon which U-NAPTR-using services can make use of
the existing IANA registries for application service tags ...
... services can make use of
the existing IANA registries for application service tags and
application protocol tags ...
... own risk.
All other application service and protocol tags are registered based
on the "specification required" option defined in [6 ...
...
o Application protocol or service tag
o Intended usage
...
... restrictions, such as limitations on the types of URIs that may be
returned for the application service.
...
... domain from
which it was retrieved; but the validity of the service reached by
resolving that URI is a matter of URI resolution ...
... Daigle, L. and A. Newton, "Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery ...
... Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782prop, February 2000. ...