What is DUNDi

DUNDi (Distributed Universal Number Discovery) is a peer-to-peer system for locating Internet gateways to telephony services. In order to do so, it publishes routes and this routes can be accessed with the use of protocols sucs as H323, IAX(2) or SIP.

From Another DUNDi site: DUNDi is essentially a trusted, peer-to-peer system for being able to call any phone number from the Internet. DUNDi works by creating a network of nodes called the "DUNDi E.164 Trust Group" which are bound by a common peering agreement known as the General Peering Agreement or GPA. The GPA legally binds the members of the Trust Group to provide good-faith accurate information to the other nodes on the network, and provides standards by which the community can insure the integrity of the information on the nodes themselves. Unlike ENUM or similar systems, DUNDi is explicitly designed to preclude any necessity for a single centralized system which could be a source of fees, regulation, etc.