Liaison statement
In Response to Member State consultation on closure of delegation of E.164 country codes in the Domain Name System in e164.arpa

The Internet Architecture Board (IAB) has noted ITU-T TSB Circular 123, which
solicits “Member States’ views on the possible closure of the ENUM system under
e164.arpa”.

The IAB wishes to clarify the architectural and operational context of
e164.arpa, as well as the respective roles of the involved parties.

The e164.arpa domain is part of the “arpa” domain, for which the IAB has
responsibility, in cooperation with the Internet Corporation for Assigned Names
and Numbers (ICANN), as described in RFC 3172. The IAB has delegated the
operation of the e164.arpa zone to the RIPE NCC, which acts as the designated
operator on its behalf, as documented in the IAB instructions to RIPE NCC and
consistent with the cooperative framework described in RFC 3245.

As described in RFC 3245, ENUM was developed through coordination between the
IETF and ITU-T, with delegation of E.164 numbering resources consistent with
their administration by ITU Member States. These arrangements reflect
long-standing agreed roles and procedures among the IAB, ITU-T, and the
designated operator, dating back to 2002, which have provided stability and
clarity over time. RFC 6116 is the current IETF Standards Track specification
for ENUM. ENUM domain names within e164.arpa are derived from E.164 numbers and
delegated in accordance with the E.164 numbering plan. The ENUM protocol and
its use of the DNS are specified by the IETF.

The IAB recognizes that the consultation initiated by ITU-T to solicit input
from Member States may provide useful operational perspectives. At the same
time, such consultation should not, on its own, determine the disposition of
the e164.arpa domain nor the status of the ENUM system. Decisions affecting the
technical status of ENUM, including any consideration of transitioning RFC 6116
to Historic status, are to be made through the open, consensus-driven standard
processes at the IETF, informed by input from all relevant stakeholders,
including ITU-T Study Group 2.

Further, any decision to retire the use of e164.arpa would require coordination
across the relevant technical and operational bodies, including the IAB, RIPE
NCC, and ITU-T. Such coordination reflects the long-standing arrangements
between the IAB, ITU-T, and the designated operator for e164.arpa (RIPE NCC),
and is necessary for any changes to its operation.

The IAB remains committed to working collaboratively with ITU-T, RIPE NCC, and
other stakeholders to ensure that any future actions concerning ENUM and
e164.arpa are undertaken in a manner consistent with established roles,
responsibilities, and open processes.