A basic building block for communication is the socket.
A socket is an endpoint of communication to which a name may be
Each socket in use has a type
and one or more associated processes.
Sockets exist within communications domains.
Domains are abstractions
that imply both an addressing structure (address family) and a set of
protocols which implement socket types within the domain (protocol
Communications domains are introduced to bundle common properties
of processes communicating through sockets.
One such property is the
scheme used to name sockets.
In the UNIX domain, sockets are named with UNIX pathnames; for example,
a socket may be named
exchange data only with sockets in the same domain (it may be possible to
cross between communications domains, but only if some translation process
system socket interface facilities
support several separate communications domains: for example, the
for on-system communication; and the Internet domain, which is used by
processes that communicate using the DARPA standard communication
The underlying communication facilities provided by these domains have a
significant influence on the internal system implementation as well as the
interface to socket facilities available to a user.
For example, a socket operating in the UNIX
domain sees a subset of the
error conditions that are possible when operating in the Internet
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 -- 02 June 2005