Update of Legacy IANA Registrations of Enumservices
updates
- rfc-3762 — Telephone Number Mapping (ENUM) Service Registration for H.323
- rfc-3764 — enumservice registration for Session Initiation Protocol (SIP) Addresses-of-Record
- rfc-3953 — Telephone Number Mapping (ENUM) Service Registration for Presence Services
- rfc-4002 — IANA Registration for Enumservice 'web' and 'ft'
- rfc-4143 — Facsimile Using Internet Mail (IFAX) Service of ENUM
- rfc-4238 — Voice Message Routing Service
- rfc-4355 — IANA Registration for Enumservices email, fax, mms, ems, and sms
- rfc-4415 — IANA Registration for Enumservice Voice
- rfc-4769 — IANA Registration for an Enumservice Containing Public Switched Telephone Network (PSTN) Signaling Information
- rfc-4969 — IANA Registration for vCard Enumservice
- rfc-4979 — IANA Registration for Enumservice 'XMPP'
- rfc-5028 — A Telephone Number Mapping (ENUM) Service Registration for Instant Messaging (IM) Services
- rfc-5278 — IANA Registration of Enumservices for Voice and Video Messaging
- rfc-5333 — IANA Registration of Enumservices for Internet Calendaring
Extracted elements (25)
RFC 6117 obsoleted the IANA registration section of RFC 3761, leaving existing Enumservice registrations non-conformant. This document adds the missing XML elements (class, usage, registrationdocs, etc.) to bring legacy registrations into conformance without altering their functional specifications.
The 'ifax:mailto' Enumservice uses the 'mailto' URI scheme rather than a dedicated fax-specific scheme because Internet Fax (IFAX) is defined as a profile of standard Internet mail and inherits standard Internet mail addressing conventions.
XML chunk format introduced by RFC 6117 provides machine-readable, structured Enumservice records with explicit fields for class, type, subtype, URI scheme, functional specification, security considerations, usage, and registration documents. Legacy registrations lacked several of these fields and used free-form text.
The ems:tel Enumservice implies SMS capability at the same address. The mms:tel Enumservice implies both EMS and SMS capability. However, this implication may not hold in future terminal designs, and tariff differences between services may exist.
This document only adds missing XML elements to legacy registrations as required by RFC 6117's IANA Considerations; it does not complete other sections (privacy, full IANA considerations) that RFC 6117 now requires. Those Enumservice Specifications must still be individually revised to fully conform.
For the voice:tel Enumservice, the 'tel:' URI value SHOULD be fully qualified using the global phone number form of RFC 3966. A local phone number SHOULD NOT be used unless the zone controller is certain it is unambiguously distinguishable by all clients that can access the record.
This document changes the approval requirement for Enumservice registration updates from a Standards Track, Experimental, or BCP RFC (as required by RFC 3761) to 'Specification Required', whereby the specification and request are reviewed by a Designated Expert per RFC 6117.
The 'email:mailto' Enumservice (Application-Based, Common, URI scheme 'mailto') maps E.164 numbers to email addresses, indicating the resource can be addressed to send an email. Defined in RFC 4355, updated by RFC 6118.
The 'h323' Enumservice (Protocol-Based, type 'h323', URI scheme 'h323') maps E.164 telephone numbers to H.323 endpoints via ENUM DNS lookup. Defined in RFC 3762, updated by RFC 6118.
The 'ical-access:http' and 'ical-access:https' Enumservices (Application-Based, Common) enable ENUM lookup to CalDAV calendar resources (e.g., free/busy status) over HTTP and HTTPS respectively. The 'ical-sched:mailto' variant supports iMIP-based calendar scheduling via email. Defined in RFC 5333.
The 'ifax:mailto' Enumservice (Application-Based, Subset, URI scheme 'mailto') supports Internet Fax. The mailto URI scheme is chosen because IFAX is a profile of standard Internet mail and uses standard Internet mail addressing.
The 'im' Enumservice (Application-Based, Common, type 'im', URI scheme 'im') indicates the resource is an 'im:' URI; per RFC 3861, the actual IM protocol is discovered separately rather than being specified by the Enumservice itself. Defined in RFC 5028.
The 'pres' Enumservice (Application-Based, Common, type 'pres', URI scheme 'pres') maps E.164 numbers to presence service endpoints using 'pres:' URIs, enabling telephone-number-based presence lookup. Defined in RFC 3953, updated by RFC 6118.
The 'pstn:sip' Enumservice (Application-Based, Common, URI scheme 'sip') and 'pstn:tel' (Application-Based, Ancillary, URI scheme 'tel') map E.164 numbers to PSTN telecommunication sessions; both note that a Number Portability Dip Indicator (npdi) should be used in practice per RFC 4769 Section 4.
The 'sip' Enumservice (Protocol-Based, type 'sip', URI schemes 'sip' and 'sips') enables ENUM resolution of E.164 telephone numbers to SIP Addresses-of-Record, allowing callers to reach a SIP endpoint by DNS lookup. Defined in RFC 3764, updated by RFC 6118.
The unifmsg, voicemsg, and videomsg Enumservice families (8 entries each with http, https, sip, sips subtypes) map E.164 numbers to unified messaging, voice messaging, and video messaging systems. All registered in RFC 5278, updated by RFC 6118.
The 'vcard' Enumservice (Data Type-Based, URI schemes 'http' and 'https') maps E.164 numbers to RFC 2426 vCard resources accessible via HTTP/HTTPS. Access is expected to be restricted and data comprehension may vary depending on the client's identity.
The 'voice:tel' Enumservice (Application-Based, Common, URI scheme 'tel') indicates interactive bidirectional voice capability reachable via E.164 number over PSTN or PLMN, including indirect connections via SIP/H.323 gateways. Defined in RFC 4415.
The 'vpim:ldap' Enumservice (Data Type-Based, URI scheme 'ldap') and 'vpim:mailto' (URI scheme 'mailto') map E.164 numbers to voice message routing endpoints via LDAP directory or SMTP respectively. Defined in RFC 4238.
The 'web:http' and 'web:https' Enumservices (Application-Based, Common) and 'ft:ftp' Enumservice (Application-Based, Subset) map E.164 numbers to web information sources and FTP file services respectively. Defined in RFC 4002.
The 'xmpp' Enumservice (Protocol-Based, type 'xmpp', URI scheme 'xmpp') indicates the resource is an XMPP entity, enabling ENUM lookup to reach XMPP-based communication endpoints by telephone number. Defined in RFC 4979.
IANA Enumservice Registrations registry (originally governed by RFC 3761) is updated: all 39 legacy free-form registrations are replaced with structured XML-chunk records conforming to the format defined in RFC 6117. The reference for registration procedures changes from RFC 3761 to RFC 6117.
Since RFC 6118 introduces no new technology or protocol, there are no security issues specific to this document itself. Security considerations for each individual Enumservice are inherited from their respective defining specifications.
The vcard Enumservice notes that access to fetched vCard resources is expected to be restricted, and that data comprehension may vary by client identity, acknowledging privacy-relevant access control as a design concern even if not formally a privacy-consideration element.
The vpim:ldap Enumservice identifies two key risks: malicious redirection (a rogue entry in the resolver database causing clients to connect to a fraudulent LDAP server) and denial of service (removal of the URI mapping). The vpim:mailto Enumservice adds a third: unsolicited bulk email, since ENUM maps telephone numbers to email addresses that bulk mailers can harvest.