The Client-Server Model; Creating A Connection: The Client-Server Model - HP Rp3440-4 - 9000 - 0 MB RAM Programmer's Manual

BSD Sockets Concepts

The Client-Server Model

The Client-Server Model
Typical BSD Sockets applications consist of two separate application
level processes; one process (the client) requests a connection and the
other process (the server) accepts it.
The server process creates a socket, binds an address to it, and sets up a
mechanism (called a listen queue) for receiving connection requests. The
client process creates a socket and requests a connection to the server
process. Once the server process accepts a client process's request and
establishes a connection, full-duplex (two-way) communication can occur
between the two sockets.
This set of conventions must be implemented by both processes.
Depending upon the needs of your application, your implementation of
the model can be symmetric or asymmetric. In a symmetrical application
of the model, either process can be a server or a client. In an
asymmetrical application of the model, there is a clearly defined server
process and client process. An example of an asymmetrical application is
the ftp service.
Creating a Connection: the Client-Server
Model
The following figures illustrate conceptual views of the client-server
model at three different stages of establishing a connection. The
completed steps are included in each figure.
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