Java Reference
In-Depth Information
Figure 1-5. A client/server connection
Not all applications fit easily into a client/server model. For instance, in networked
games, it seems likely that both players will send data back and forth roughly equally
(at least in a fair game). These sorts of connections are called
peer-to-peer
. The telephone
system is the classic example of a peer-to-peer network. Each phone can either call
another phone or be called by another phone. You don't have to buy one phone to send
calls and another to receive them.
Java does not have explicit peer-to-peer communication in its core networking API.
However, applications can easily offer peer-to-peer communications in several ways,
most commonly by acting as both a server and a client. Alternatively, the peers can
communicate with each other through an intermediate server program that forwards
data from one peer to the other peers. This neatly solves the discovery problem of how
two peers find each other.
Internet Standards
This topic discusses several application layer Internet protocols, most notably HTTP.
However, this is not a topic about those protocols. If you need detailed information
about any protocol, the definitive source is the standards document for the protocol.
Although there are many standards organizations in the world, the two that produce
most of the standards relevant to application layer network programming and protocols
are the Internet Engineering Task Force (IETF) and the World Wide Web Consortium
(W3C). The IETF is a relatively informal, democratic body open to participation by any
interested party. Its standards are based on “rough consensus and running code” and
