The Core Protocol Specification defines the required components and behaviors for all JXTA implementations. In order to create a JXTA implementation there may be some additional service protocols that need to be provided. The JXTA protocols specify a set of Standard Services protocols. The Standard Services protocols are optional, but their implementation is strongly recommended. Implementing these services will provide greater interoperability with other implementations and broader functionality.
The JXTA protocols specify four service protocols:
Peer Discovery Protocol (PDP)
Pipe Binding Protocol (PBP)
Rendezvous Protocol (RVP)
Peer Information Protocol (PIP)
The PDP is used for publishing and discovering any available network resource. Every network resource is represented by an advertisement (see Chapter 14). A resource can be a peer, a peergroup, a pipe, a module, or any other resource, such as disk storage or a CPU.
The PDP enables a peer to find advertisements within a specified peergroup context.
The PDP is the default discovery protocol of the World Peergroup.
Custom discovery services may choose to leverage the PDP. If a peergroup does not need to define its own discovery protocol, it may use the World Peergroup’s PDP.
The intent is for the PDP to provide the minimal but essential discovery infrastructure for building and bootstrapping high-level discovery services.
In many ...