Network Working Group                                           R. BlaneRequest for Comments: 3026                                           ITUCategory: Informational                                     January 2001                      Liaison to IETF/ISOC on ENUMStatus of this Memo   This memo provides information for the Internet community.  It does   not specify an Internet standard of any kind.  Distribution of this   memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2001).  All Rights Reserved.Abstract   Working Party 1/2, of the International Telecommunication Union   Telecommunication Standardization Sector (ITU-T) held a meeting of   its collaborators in Berlin Germany 19-26 October 2000.  The agenda   of the meeting contained several contributions regarding RFC 2916:   "E.164 Number and DNS" from the Internet Engineering Task Force's   (IETF) ENUM Working Group - more specifically, the method for   administering and maintaining the E.164-based resources in the Domain   Name System (DNS) as related to the ENUM protocol.  Consequently, in   addition to the WP1/2 collaborators, there were several members of   the IETF present to assist with the discussion of issues contained in   the aforementioned contributions.   This liaison from WP1/2 to the IETF/ISOC conveys the understandings   of the WP1/2 collaborators resulting from the discussions.1. Considerations under Question 1/2 (Numbering)   Throughout this document, the terms "administration" or   "administrative functions" refer to the provision and update of the   E.164 numerical values, to be contained in the zones of a domain name   in the "e164.arpa" domain, in the DNS.   It is noted that most ENUM service and administrative decisions are   national issues under the purview of ITU Member States, since most of   the E.164 resources are utilized nationally.   These understandings are relative only to the provision of E.164   information for DNS administrative functions, not policy or   operational functions.Blane                        Informational                      [Page 1]RFC 3026              Liaison to IETF/ISOC on ENUM          January 2001   In order to advance a common terminology for the purpose of this   liaison, we have defined the zones of a domain name as follows.   Using an example, domain name "1.5.1.5.0.2.0.4.1.3.3.e164.arpa" (as   in RFC 2916) is segmented into zones as follow:      E164.arpa - domain zone      3.3. - country code zone (1, 2, or 3 digits dependent on CC)      1.5.1.5.0.2.0.4.1. - national zone   The first understandings to be conveyed are those regarding the   responsibilities for administration of the various zones within the   "e164.arpa" domain:   o  The domain zone administration was agreed to be outside the scope      of this meeting and WP1/2.   o  For all E.164 Country Code Zone resources (Country Codes and      Identification Codes), the ITU has the responsibility to provide      assignment information to DNS administrators, for performing the      administrative function.  The ITU will ensure that each Member      State has authorized the inclusion of their Country Code      information for input to the DNS.  For resources that are spare or      designated as test codes there will normally be no entry in the      DNS.  However, the ITU will provide spare code lists to DNS      administrators for purposes of clarification.  The entity to which      E.164 test codes have been assigned will be responsible for      providing any appropriate assignment information to DNS      administrators.   o  The administration of National Zone numbering information is      determined by the type of Country Code resource that a National      Zone is behind:      *  The national zone, for geographic resources, is a national         matter and is, therefore, administered by the ITU Member         State(s) to which the country code is assigned.  In an         integrated numbering plan, e.g., CC "1", each Country within         the plan may administer their portion of the resource in a         different manner.      *  For national zone resources behind the Country Codes assigned         to and shared by Networks, the entity to which the resource is         assigned provides the E.164 assignment information, to DNS         administrators for performing the administrative function.Blane                        Informational                      [Page 2]RFC 3026              Liaison to IETF/ISOC on ENUM          January 2001      *  For national zone resources behind the Country Codes assigned         to and shared by Groups of Countries, the administrative entity         identified by the Countries of the Group provides the E.164         assignment information, to DNS administrators, for performing         the administrative function.  Note that the creation of this         category is dependent upon the approval of draft Recommendation         E.164.3.   o  Each of the administrative entities responsible for the      administration of resources within the zones (as identified above)      is individually and separately responsible for ensuring that DNS      administrators are aware of appropriate changes to their resources      once they have agreed to their input into the DNS.   o  Assigned geographic E.164 resources, for all zones, not authorized      for input by the appropriate administrative entity will not be      entered into the DNS under any circumstance.  For example, if the      ENUM service is not approved for use in a country, by the      appropriate ITU Member States, the E.164 numbers of that country      will not be input to the DNS.   o  With regard to Number Portability, it was agreed that WP1/2 would      further study this issue, in the context of ENUM.  However, it is      currently understood that this study and its result will not      impact the IETF and its work.   o  The study being undertaken within WP1/2 (referred to above) will      also attempt to identify options and provide guidance to assist      those entities charged with the task of providing the      administrative information to DNS administrators.   o  All administrative entities, including DNS administrators, will      adhere to all the applicable tenets of all pertinent ITU      Recommendations, e.g., E.164, E.164.1, E.190, and E.195, with      regard to the inclusion of the E.164 resource information in the      DNS.   o  The ITU, IETF, and IAB will jointly cooperate fully to ensure that      the agreed administrative procedures to accommodate the above      understandings, and any other mutually agreed appropriate future      understandings, will be implemented and adhered to on an ongoing      basis.  The ITU may request the consultation of the WP1/2 experts      as necessary and as prescribed in Resolution 20.Blane                        Informational                      [Page 3]RFC 3026              Liaison to IETF/ISOC on ENUM          January 20012. Additional items below are from Q.10/2 Rapporteur Group (Service   Issues)   o  The issues surrounding number portability are to be addressed in      the draft supplement to Recommendation E.370   o  This issue surrounding freephone service was expanded to include      other global services (i.e., International Premium Rate Service      and International Shared Cost Service).  Preliminary findings      would indicate that routing the call to the appropriate      destination will depend on successfully receiving information      about the geographic point of origination (e.g., calling      "telephone Number").  A proxy server would process such      information and either redirect or forward the call (based on the      proxy owner's decision) on to the appropriate destination.   o  The issue surrounding selection of the IP gateway within a PSTN-      to-IP call flow may depend on options that may be available to      telephony carriers in such selection.   The WP1/2 collaborators thank their IETF counterparts who attended   this meeting and assisted in the resolution of these issues.   Any questions regarding the contents of this liaison should be   referred to the WP1/2 Chairman Roy Blane at Roy_Blane@inmarsat.com.3. Security Considerations (added by the IESG)   The ENUM solution uses the Domain Name System (DNS) for storage of   information.  Delegation and distributed administration is done   according to DNS routines.  The E.164 numbers are though distributed   according to a different algorithm than domain names.   This Liaison Statement describes how mapping E.164 number   administration and DNS administration can work together, and how   further discussions are delegated to each administrative body for the   country codes in E.164 space.   If delegation and mapping is not done carefully between E.164 and DNS   there is a risk of "napping" of E.164 numbers when they are stored in   DNS.  It is also important that the DNS strictly hierarchal system is   preserved (see RFC 2826 [1]).4. References   [1] IAB, "IAB Technical Comment on the Unique DNS Root", RFC 2826,       May 2000.Blane                        Informational                      [Page 4]RFC 3026              Liaison to IETF/ISOC on ENUM          January 20015. Author's Address   Roy Blane   ITU   EMail: Roy_Blane@inmarsat.com   URI:   http://www.itu.intBlane                        Informational                      [Page 5]RFC 3026              Liaison to IETF/ISOC on ENUM          January 20016. 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