Ad Hoc US Study Group A ENUM
Stephen J. Engelman
N. Glenville Road
E164.arpa and Tier 1 Registries discussion
contribution has been prepared by WorldCom to assist Ad Hoc SGA in its
discussions, and it should not to be considered a binding proposal on
or any of its representatives.
reserves the right to change, amend or withdraw this
at any time.
The following are discussion points on some of the issues
raised at the February SG A ENUM meeting:
SG A Queston : Should E.164.arpa be an implemenation of ENUM in
Comment: Yes, if there is to be an ENUM
implementation in the US, then the e164.arpa domain should be the
single root for ENUM service. Alternatively, implementations using
multiple root servers should not be considered due to performance issues
associated with multiple ENUM lookups.
Figure 1 depicts a potential US ENUM DNS structure using the
Potential US ENUM DNS Implementation
SG A Queston: What are the implications for other
countries in the NANP?
Comment: Canada and the NANP Carribean countries could
participate in a US Tier 1 structure, or they could alternatively provide
their own Tier 1 DNS. Should Canada or the NANP Carribean countries decide
to have their own Tier 1 DNS, then the e164.arpa domain will need to have
a 1+NPA table for routing to the US, Canadian or Carribean Tier 1 domains.
SG A Question: Should there be multiple Tier 1 Registries
(1.E164.arpa) in the US (e.g. regionalization of Tier 1 domains based on
area code with no area code in more than one Tier 1)?
Comment: It is premature to determine if its desireable to have
multiple Tier 1 Registries. Descriptions of Tier 1 and Tier 2 functional
requirements and administrative issues need to be developed and understood
prior to making this decision.