IANA
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... independent of the protocol that may be used to offer it. Each
application service will be associated with an IANA-registered tag.
For example, retrieving mail is a type of application service that
...
... application protocol" is used to implement the application
service. These are also associated with IANA-registered tags. Using
the mail example above, "POP3" and "IMAP4 ...
... based location of services. This should be easy for applications to
use -- a few simple IANA registrations, and it's done.
...
...
The "app-service" must be an IANA-registered service; see Section 7
for instructions on registering new application service tags ...
... IANA Considerations ...
...
This document calls for two IANA registries: one for application
service tags, and one for application protocol tags ...
... Application Service Tag IANA Registry ...
...
o Application Service Tag: A string conforming with the IANA-
registered-service defined in section 6.5.
...
... Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. ...