2.7.3 Telephone Number Mapping (enum)

NOTE: This charter is a snapshot of the 59th IETF Meeting in Seoul, Korea. It may now be out-of-date.

Last Modified: 2004-01-22

Patrik Faltstrom <paf@cisco.com>
Richard Shockey <rich.shockey@neustar.biz>
Transport Area Director(s):
Allison Mankin <mankin@psg.com>
Jon Peterson <jon.peterson@neustar.biz>
Transport Area Advisor:
Allison Mankin <mankin@psg.com>
Mailing Lists:
General Discussion: enum@ietf.org
To Subscribe: enum-request@ietf.org
In Body: subscribe
Archive: ftp://ftp.ietf.org/ietf-mail-archive/enum/
Description of Working Group:
This working group has defined a DNS-based architecture and protocol [RFC 2916] by which an E.164 number, as defined in ITU Recommendation E.164, can be expressed as a Fully Qualified Domain Name in a specific Internet Infrastructure domain defined for this purpose (e164.arpa). The result of the ENUM query is a series of DNS NAPTR resource records [RFC2915] which can be used to contact a resource (e.g.URI) associated with that number.

The Working Group proposes to advance RFC 2916 from Proposed Standard to Draft Standard.


E.164 numbers are globally unique, language independent identifiers for resources on Public Telecommunication Networks that can support many different services and protocols. E.164 numbers are used to identify ordinary phones, fax machines, pagers, data modems, email clients, text terminals for the hearing impaired, etc.

A prospective caller may wish to discover which services and protocols are supported by the terminal named by a given telephone number. The caller may also require more information than just the telephone number to communicate with the terminal.

The holder of an E.164 number or device may wish to control what URI's, are associated with that number.

Working Group Revised Goals and Scope:

1. The working group will update RFC 2916 to reference the DDDS system (revision of RFC 2915) and advance RFC 2916 to Draft Standard.

2. The working group will examine and document various aspects of ENUM administrative and/or operational procedures as Informational. Issues to be considered include privacy and security considerations in storing ENUM related data as well as validation and authentication of data, including DDDS NAPTR records in the DNS. The working group will coordinate activities in these areas with the DNSEXT WG and PROVREG WG when appropriate.

3. The Working Group will continue to maintain appropriate contact and liaison with standards bodies and groups, specifically ITU-T SG2, in order to provide technical or educational information as needed, such as the appropriate use of DNS. The Working Group will encourage the exchange of technical information within the emerging global ENUM community as well as documentation on practical experiences with implementations or administration of RFC 2916.

Goals and Milestones:
Done  Initial draft of Service ENUM Requirements
Done  Initial draft of ENUM Protocol
Done  Revised draft of ENUM Protocol
Done  Submit ENUM Protocol document to IESG for publication as Proposed
Done  Revise and update RFC 2916 appropriate to DDDS (revision of 2915)
Done  ENUM service registrations for SIP and H.323
Aug 03  Document appropriate ENUM Security and Privacy Issues (Informational)
Nov 03  Document appropriate ENUM Registration and Provisioning Procedures (Informational)
  • - draft-ietf-enum-rfc2916bis-07.txt
  • - draft-ietf-enum-h323-01.txt
  • - draft-ietf-enum-sip-01.txt
  • - draft-ietf-enum-msg-00.txt
  • - draft-ietf-enum-webft-00.txt
  • - draft-ietf-enum-pres-00.txt
  • Request For Comments:
    RFC2916 PS E.164 number and DNS
    RFC3482 I Number Portability in the Global Switched Telephone Network (GSTN): An Overview

    Current Meeting Report

    Telephone Number Mapping WG (enum)
    IETF 59 Soeul, Korea
    Wednesday, March 3, 2004
    0900-1130 AM
    CHAIRS: Patrik Faltstrom <paf@cisco.com>
                  Richard Shockey 
    SCRIBE: Spencer Dawkins <mcsr-labs.org>
    AGENDA BASHING (5 min)  ( appointment of scribe etc)
    Status of 2916bis ... Allison Mankin Transport AD
    - problem with IANA - and our relationship is not formal, no contract with 
    us, just handshake agreements
    - they have a very significant staffing problem with a huge backlog.
    - IESG made a list - high delay, extremely high backlog, high priority was so 
    backlogged that they had a hard time prioritizing
    - 2916bis is part of the backlog
    - no tracker in place today (as we have with I-D trackers)
    - we started this action before the document was approved, but had no way to 
    know there was a problem
    - if registries are being blocked, please let us know so we can 
    - all the registration documents are blocked - iFax, VPIM, at least six 
    - today's presentations are about services that are rolling out now - what 
    else do we need to say?
    - registries acting in faith that I-Ds will not change before RFC 
    - chairs to send a formal letter to IESG - please provide inputs to this 
    - revs of other services - get them in sooner, rather than later, OK?
    IFAX Registration - Richard Shockey- Claudio Allocchio Fax WG co-chair
    - this document also in the IANA queue
    - any difficulties with this document?
    - Claudio - security and privacy sections very skinny - should we expand 
    this stuff or leave it and point elsewhere?
    - web and FT documents contained all considerations
    - IFAX should match these documents - is this a simple revision, or 
    any objections to this document? none in the room
    - chair preference is to add this text and send it to the IESG
    - editors say no problem adding this text
    - no last call required
    - Allison - document user interested in fax, not other services, not going to 
    look at an H.323 document for these sections
    - bits are free
    A. Discussion of  Jon Peterson's presence document ... (10 m)
    - not a lot of feedback received so far - want more
    - adds a pres: URI scheme, resolves to XMPP, SIMPLE, etc. - presence 
    - PSTN telephones still need work (states, location attributions) - 
    especially for wireless
    - not a lot of changes since initial draft (name change plus 
    references update
    - James - what is XMPP status now? RFC? still an I-D, but have been 
    approved by IESG
    - what about press: schema? Also passed IESG, some time back
    - move forward to WGLC? any objection? Is this urgently needed? it is 
    implemented, will move forward.
    B. A report on the results of the ETSI ENUM Plugtest Workshop (R. 
    Stastny  15 M)
    - last week, hosted by ETSI, 55 attendees (lower because of 3GPP 
    conflicts, etc.)
    - presentations available at ETSI website
    - spent time on both user ENUM and carrier ENUM
    - 14 presentations on user ENUM
    - privacy and data security viewed as more critical than regulatory 
    issues for ENUM rollout
    - no "killer application", but strong focus for VoIP
    - 4 presentations on carrier ENUM
    - huge number of possible implementations, including MMSC, SMSC, SMPP 
    gateway, MSSP, HLR/HSS, ...)
    - Verisign presentation focused on registries and registry 
    - applications/implementations vary more widely than user ENUM
    - two Plugfests upcoming, in October and late November/early December
    - Plugfests and related workshops are open to anyone, not just ETSI 
    - www.etsi.org/plugtests for details
    C. A report on APRICOT ENUM BoF  (J Seng 10M)
    - ENUM/SIP BoF last week
    - James focused on TWNIC trials (other participants presenting 
    - regulators have allocated 0944 for trials, but production SIP/ENUM using 
    unofficial block(?) of 070
    - 802.11b SIP phones for 50 dollars, also being distributed with 
    two-year contract commitments to carriers
    - 64111 allocated (10,000 numbers), with no telco involvement
    - all countries eager to do trials, but ENUMs mean different things to 
    different people
    - have issues getting e164-arpa to work under delegation - operating under 
    ccTLD for now
    - forming Asia Pacific ENUM Technical Forum, details by July timeframe
    - what are regulator difficulties? vary by country. Helps if you work in the 
    same building as regulators. Ongoing discussions with regulators in China 
    and Japan.
    - Taiwan is a special case (86 not in ITU tables at all)
    D. CN-NIC focussing their ENUM trials in China  (15M Sheldon Lee)
    - 80M Internet users in China, 260M mobile phones, 255M fixed phones at 
    yearend 2003
    - trials started in July 2001, 6.8.e164.arpa delegation in September 2002, 
    opened for public testing in December 2003, performance testing in 
    September 2003
    - 3-tier ENUM resolution in China, registration plan studied but not 
    - 7741 queries in February 2004 (after spring festival in January)
    - 260 users and 520 ENUMs registrations
    - ENUM trial platform includes SIP UAs, IP/GSTN gateway, 
    ENUM-enabled SIP proxy, only ENUM users can register SIP account
    - ENUM server pressure is how to support large number of queries with 
    dynamic update
    - 94% query responses with 2-second latency when not using caching
    - participating in both ITU-T and IETF ENUM, and in several workshops
    - promotion of ENUM/SIP in China is big challenge - no Internet phone 
    license issued for end users in China
    - what service is most beneficial in China? SIP registration, exchange ENUM 
    in browser address bar
    - finished with SIP call to person in the second row of audience, and to 
    China ("hello to IETF")
    E. JP-NIC discussing ENUM in Japan
       ETJP(Enum Trial Japan) web page is 
    http://etjp.jp/english/ (15M Kazunori Fujiwara)
    - 1-year trial activity, started in September 2003
    - verify communication and applications technologies, and clarify 
    relevant issues
    - working groups - Privacy and Security, and DNS
    - using +81 numbers
    - includes SIP server, SOHO router, DNS, applications
    Implementation Experience R. Stastny for Larry Conroy
    - 2916bis and DDDS ambiguous - example from NAPTR RR regulart 
    expression interpretation, and room was not sure what right answer was
    - multiple field delimiter characters are proving troublesome - limit to one 
    - Patrik - we have inherited regular expression, and we can't fix it 
    ourselves - must fix NAPTR itself - Patrik has action to close this loop
    - processing order - SERVICE before ORDER? RFC 3405 seems 
    contradictory - answer, process SERVICE before ORDER? but this answer is too 
    easy, if we need to choose between services based on preferences - but this 
    seems to require FQDN? but that's what we have in ENUM anyway - what about 
    privacy aspects of including this stuff in DNS instead of SIP? may have 
    overriding preferences - put that in DNS - maybe we shouldn't touch the 
    ORDER field - but this is a negotiation between the endpoints and 
    shouldn't be prescribed
    - does ENUM always return a single rule? multiple contact points, which may 
    not all be SIP contact points? e-mail, etc.
    - MUST process non-terminal NAPTR? we don't
    - is summary 2916bis-compliant?
    - Richard - suggests that people who have implementation issues 
    collaborate with Larry Conroy on his draft
    - we have issues with these RFCs, and fixing them will take time. How to 
    move forward? "BCP" for an I-D?
    - Patrik would also like to maintain the Conroy draft as experience grows - 
    need to document workarounds - this should become a BCP document
    Combine JPRS work with existing implementation document make this draft a 
    working group document
    F. Our Korean Hosts KR-NIC will update us on their ENUM trial 
    status... <Sungwoo Shin>
    - launched public trial October 2003-January 2004, national workshop last 
    December, national standards requivalent to RFCs and New Standard 
    - see lots of possibilities in Asia-Pacific region (not just Korea)
    - ENUM APIs, telephony, DNS, registration
    - 60-percent of telephone numbers are mobile - don't distinguish between 
    PSTN and mobile numbers
    - still developing APIs - ENUM FAX, ENUM H.323, telephony on a website
    - service council moving to profit model setup, commercial services
    - Korea still waiting for country to sign with ITU - registry problem - 
    have been negotiating with goverment for two years
    - Tier 1 registry selection is quite important
    - not sure why other countries are working on ENUM? effect of ENUM on 
    Telecommunication Policy? charm of ENUM, compared to domain names?
    - mobile environment important to ENUM deployment
    - expect regulations, AAA, business model in 2004, commercial service in 
    - Japan shipping H.323 now, with numbering plan assigned to 
    commercial service - Japan using special numbers for VoIP calls, and Korea 
    expects to do the same thing
    - is priority in your service the number to connect? - want to keep up with 
    ENUM in real world. Telcos think people would prefer mobile device 
    numbers to other device numbers - all this is a hard decision for us
    - does Korean government assign special numbers? yes - what is official 
    VoIP protocol? H.323, but SIP is good...
    G. Plans to close the trial and go commercial in Austria with ENUM and the 
    ENUM-only number range (+43780)  (R. Stastny 10-15)
    - Austria has proved concept with ENUM trial
    - ENUM ready for deployment, so trial is ending
    - need legal framework, need official platform (AK-TK)
    - ENUM will be a working group within AK-TK regulatory body
    - basic issues are solved, but opt-in for residential numbers has 
    problems - see Metcalf's law - how do we get users into ENUM?
    - ENUM for IP-PBX with direct dial-in
    - ENUM-only ranges for IP Communications
    - mobile numbers validated via SIM card
    - IP communication bigger than VoIP, and other services growing in 
    - no definition of how routing will be done
    - punt PSTN-only numbers to PSTN gateways
    - pre-paid cards add validation/identification considerations
    - adding mms:mailto and mms:sip
    - one company in Gernany giving out ENUM numbers commercially now
    - interesting "primary goals" slide...
    H. ENUM Implementation Redux - Willheim Wimmhitter
    - case sensitivity (we only use numbers in ENUM, but we still manage to 
    break some clients that assume last character is a regexp delimiter) - 
    don't use this flag if you can avoid it
    - order traversal (as previously described)
    I. ENUM WG issues
    - could we hibernate? still some implementation experience to capture
    - can we get a link to these presentations? Richard will provide this
    - no discussion of provisioning issues - OK for trials, but probably not for 
    commercial offerings
       1. Status of Privacy-Security and other drafts still in the pipeline


    ENUM and Presence
    Report from ETSI ENUM Plugtest Workshop
    Status on ENUM@CNNIC
    ENUM Activities in Japan
    KR ENUM Trial Status Update
    The Austrian ENUM Trial is closing down
    ENUM Implementation Redux
    Experiences from implementing ENUM system