The Domain Registrar provides services to register & manage domains. The Domain Registrar also provides the Domain Information System with real-time domain information. Any changes to a domain such as ownership, routing, or cryptography will automatically notify the DIS. Another important feature of the Domain Registrar is signing domain certificates.
The Domain Information System hosts all domain certificates and serves them on request. Clients send requests to the DIS to retrieve a domains routing information and cryptographic details in order to establish a UDSP stream. The Domain Information System takes in a hostname and responds with the corresponding certificate.
Domain certificates provide hostname routing and cryptographic details. Clients use a D.C. to establish a UDSP stream with a destination domain.