DNS

ENUM typically uses a 3 layer hierarchy

Tier 0: ENUM Root Level
- Top level domain for telephone numbers is: e164.arpa
- DNS look up to find the country for a specific E.164-Country Code (CC)
- Manager: IAB; Registry: RIPE NCC; Registrar: ITU TSB .e164.arpa
Tier 1: ENUM CC Level - DNS look up to find the ENUM subscribers
- Manager: ITU Member State; Registry: choice of Manager; ENUM Registrar: national choice
- swedish example: 6.4.e164.arpa - registry: NIC-SE (as of 13 Dec. 2002)
Tier 2: ENUM E.164 Number Level
- DNS stores a list over different internet based addresses (URIs) in NAPTR records
- Thus a look up ⇒ a list over different internet based addresses associated with each E.164-number
- Manager: E.164-subscriber; DNS Service Provider: choice of Manger

For details see RFCs 6116 and 6117 and RFCs 3401, 3402, 3403, 3404 (replaced RFC 2915).

Slide Notes

P. Faltstrom and M. Mealling, “RFC 3761: The 164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDS) Application (ENUM)”, IETF RFC 3761, Obsoleted by RFCs 6116 and 6117, April 2004 http://www.rfc-editor.org/rfc/rfc3761.txt Links to an external site.

Bradner, L. Conroy, and K. Fujiwara, ‘The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)’, Internet Request for Comments, vol. RFC 6116 (Proposed Standard), March 2011, Available at http://www.rfc-editor.org/rfc/rfc6116.txt Links to an external site..

Hoeneisen, A. Mayrhofer, and J. Livingood, ‘IANA Registration of Enumservices: Guide, Template, and IANA Considerations’, Internet Request for Comments, vol. RFC 6117 (Proposed Standard), March 2011, Available at http://www.rfc-editor.org/rfc/rfc6117.txt Links to an external site..

M. Mealling, “Dynamic Delegation Discovery System (DDDS) Part One: The Comprehensive DDDS”, Internet Request for Comments, RFC Editor, RFC 3401 (Informational), ISSN 2070-1721, October 2002 http://www.rfc-editor.org/rfc/rfc3401.txt Links to an external site.

M. Mealling, “Dynamic Delegation Discovery System (DDDS) Part Two: The Algorithm”, Internet Request for Comments, RFC Editor, RFC 3402 (Proposed Standard), ISSN 2070-1721, October 2002 http://www.rfc-editor.org/rfc/rfc3402.txt Links to an external site.

M. Mealling, “Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name System (DNS) Database”, Internet Request for Comments, RFC Editor, RFC 3403 (Proposed Standard), ISSN 2070-1721, October http://www.rfc-editor.org/rfc/rfc3403.txt Links to an external site.

M. Mealling, “Dynamic Delegation Discovery System (DDDS) Part Four: The Uniform Resource Identifiers (URI)”, Internet Request for Comments, RFC Editor, RFC 3404 (Proposed Standard), ISSN 2070-1721, October 2002 http://www.rfc-editor.org/rfc/rfc3404.txt Links to an external site.

Transcript

[slide221] So how does ENUM work? Well, it's leverages off DNS. So we have a tier 0 which is the root and it is e164.arpa. Inside that we are going to look up the country code. That will take use to a tier 1 provider, and they will handle the next level down which will take us to a tier 2 provider, and they will then actually do the mapping between the numbers and the SIP URIs.