The MODERN working group will define a set of Internet-based mechanisms for the purposes of managing and resolving telephone numbers (TNs) in an IP environment. Existing mechanisms for these purposes face obsolescence as the voice communications infrastructure evolves to IP technology and new applications for TNs become possible. The traditional model of a TN having an association to a single service provider and a single application is breaking down. Its use as a network locator is going away, but its use as an identifier for an individual or an organization will remain for some time. Devices, applications, and network tools increasingly need to manage TNs, including requesting and acquiring TN delegations from authorities. The working group will define a framework for the roles and functions involved in managing and resolving TNs in an IP environment. This includes a protocol mechanism for acquiring TNs, which will provide an enrollment process for the individuals and entities that use and manage TNs. TNs may either be managed in a hierarchical tree, or in a distributed peer-to-peer architecture. Privacy of the enrollment data and security of the resource will be primary considerations. Additionally, the working group will deliver a protocol mechanism for resolving TNs which will allow entities such as service providers, devices, and applications to access data related to TNs, possibly including caller name data (CNAM). Maintaining reliability, real time application performance, security and privacy are primary considerations. The working group will take into consideration existing IETF work including ENUM, SPEERMINT, STIR, and DRINKS. The work of this group is limited to specifying a solution for TNs and covers any service that can be addressed using a TN. Expanding the work to other identifiers is out of scope. Solutions and mechanisms created by the working group will be flexible enough to accommodate different policies, e.g., by different regulatory agencies. The work group will deliver the following: - An architecture overview document that includes high level requirements and security/privacy considerations - A document describing the enrollment processes for existing and new TNs including any modifications to metadata related to those TNs - A document describing protocol mechanisms for accessing contact information associated with enrollments - A document describing mechanisms for resolving information related to TNs