Grapevine was developed at Xerox by the same research group the developed the Ethernet. Among other things, Grapevine provides a distributed, replicated database, implemented by servers residing at various locations around the internet. Clients can query, add new entries or modify existing entries in the database. The Grapevine database maps character string keys to entries called RNames. Each server registers the transport address at which its service can be accessed and every instance of an interface is registered as an individual entry.
Individual entries map instances to their corresponding transport addresses.
The type of an interface, which consists of a list of individual RNames . Group entries contain RNames that point to servers providing the service having that group name. Normally, a client will send a request, the server will execute the request and then return a response to the client. Just hang forever waiting for the reply that will never come. This models regular procedure call.