RFC3026 - Liaison to IETF/ISOC on ENUM

Network Working Group R. Blane

Request for Comments: 3026 ITU

Category: Informational January 2001

Liaison to IETF/ISOC on ENUM

Status 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.

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 RFC2916:

"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.

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 RFC2916) 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.

* 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.

2. 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 RFC2826 [1]).

4. References

[1] IAB, "IAB Technical Comment on the Unique DNS Root", RFC2826,

May 2000.

5. Author's Address

Roy Blane

ITU

EMail: Roy_Blane@inmarsat.com

URI: http://www.itu.int

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