B2B Integration : A Practical Guide to Collaborative E-commerce

B2B to P2P Evolution 475
1. Core Platform — This layer enables interoperability among all
P2P devices. It encapsulates services that are mandatory for P2P
networking, such as peers, peer groups and peer monitoring.
2. Services — This layer encapsulates the non-mandatory but desired
network services, such as searching, indexing and file sharing.
3. Applications — This layer includes P2P applications, such as instant
messaging, content management and delivery.
JXTA protocols, messages and advertisements
JXTA protocols are the common threads among JXTA peers. Each
protocol, as defined by JXTA, involves exchange of one or more
messages (based on a pre-defined format) and advertisements among
the peers.
A JXTA message consists of an envelope, which defines fields such
as destination address and source address and a stack, which contains
the body of the message and its relevant information (see Figure 16.4).
An advertisement is an XML-structured document and, therefore,
platform independent, that names, describes and publishes the existence
of a resource, such as a peer, a peer group, a pipe, or a service.
Envelope
Stack of
Messages
9 Ixta:// I Envelope Version
i C«1MIRWeMmBttMaiiaiIIHBIHIHH^iMH«;
Figure 16.4. — JXTA message definition