A "thin" registry-registrar model is currently used for the .org
registry. In this model, information associated with each registered domain name
is distributed between the registry and the sponsoring registrar. The registry
maintains delegation information needed to publish the .org zone, while the
registrar maintains information describing the registrant and other contacts
(such as technical, administrative and billing contacts) associated with the
domain. The NSI Registry-Registrar Protocol (RRP) (described in RFC 2832) is
used to exchange information between registrars and the .org registry in real
time. Registrants register and manage domain name information through one of
several ICANN-accredited registrars.
A "thick" registry model is one in which the registry maintains
copies of all information associated with registered domains, including
registrant and contact information. Registrars typically maintain their own
copies of registration information, thus registry-registrar synchronization is
required to ensure that both registry and registrar have consistent views of the
technical and social information associated with registered domains. The
Extensible Provisioning Protocol (EPP), first published by VGRS and later
adopted by the Internet Engineering Task Force (IETF) provreg working group,
provides features to support both thick and thin registry models.
The basic registrant-registrar-registry model for the .org gTLD has become
familiar and stable over the course of three years of ongoing operations. The
UIA Team will preserve the "thin" registry model as-is, initially
continuing support for RRP while gradually transitioning to a "thin"
registry served by the Extensible Provisioning Protocol.
Continued use of RRP at the outset of registry operations provides several
advantages that help preserve the stability of the .org gTLD:
- Registrars have gained significant operational and business logic
experience with RRP. Initial use of RRP using the existing VGRS
infrastructure ensures that transition risk is absolutely eliminated.
- VGRS has been able to optimize its RRP implementation to the point of
being able to support peaks of more than 150 million transactions per day,
and a sustained daily average of more than 130 million transactions per day.
No other registry operator has demonstrated similar processing capabilities
- EPP is not yet an IETF proposed standard. There is significant risk in
deploying an implementation of EPP before the first proposed standards are
published as the protocol is still evolving, and revisions mean code changes
for both registry and registrars.
- RRP is stable. Initial use of RRP will allow for initial registry
operations that have no timetable dependencies on the development of EPP.
- Both registries and registrars are still gaining experience with EPP.
Initial implementations are likely to have defects and performance
limitations that can only be discovered and corrected over time.
The UIA Team will use the existing VGRS RRP implementation, designed and
developed by the original authors of the protocol, at the start of registry
operations. This implementation has been refined, optimized and tailored to
ICANN processes over the course of three years of high-pressure, high-volume
registry operations, providing registrars with levels of real-time service and
performance unmatched in the domain name industry. Satisfactory levels of
stability, reliability and error-free performance are guaranteed with this
implementation of RRP.
While initial use of RRP provides significant stability advantages at the
start of registry operations, support for EPP is required in the future. EPP
includes many features and improvements that help make the transition possible
and worthwhile, including:
- Extensibility (adding new features, such as support for ENUM and DNS
security) gained through the use of XML and a well-defined protocol extension
- Multiple transport protocol options,
- Improved features to authenticate and streamline transfer operations,
- Real-time client notification and message queuing,
- Support for IPv6 name server addresses,
- Improved pre-sales query mechanisms, and
- Specification refinement and eventual standardization through the open
processes of the IETF.
VGRS has been developing implementations of EPP for several months, and has
already released an implementation for the provisioning of Internet keywords
based on Internet-Draft EPP specifications. An active project to develop an
implementation for use in the .com and .net registries has been following the
ongoing efforts of the IETF's provreg working group, with finalization and
deployment planning dependent on the publication of proposed standards by the
Our early implementations of EPP have already been subjected to several
rounds of development and formal quality assurance testing. With protocol
stability and transition costs being a significant concern in the ongoing
management of .org, the UIA team will fully deploy an implementation of EPP only
after the IETF has published Proposed Standard protocol documents. Free client
Software Development Kits (SDKs) that interoperate with other EPP servers will
be available in multiple programming languages to minimize the amount of
software development required of registrars. An isolated Operational Test &
Evaluation (OT&E) environment will be available for registrar testing prior
to "live" operations, allowing registrars to develop and test their
software systems with no risk to "live" data or systems. Issues,
defects, and errors noted during OT&E testing will be corrected rapidly and
deployed in both the OT&E and "live" environments, ensuring that
both environments use the exact same software code bases and that transition
will require little more than minor changes to client configuration parameters.
A detailed description of the transition plan for retiring RRP and deploying
EPP can be found in Section C22.