Socket Address Spaces

Sockets exist in communication domains. A socket domain is an abstraction that provides an addressing structure and a set of protocols. Sockets connect only with sockets in the same domain. Twenty three socket domains are identified (see <sys/socket.h>), of which only the UNIX and Internet domains are normally used in Solaris 7 and compatible operating environments.

Sockets can be used to communicate between processes on a single system, like other forms of IPC. The UNIX domain (AF_UNIX) provides a socket address space on a single system. UNIX domain sockets are named with UNIX paths.

Sockets can also be used to communicate between processes on different systems. The socket address space between connected systems is called the Internet domain (AF_INET). Internet domain communication uses the TCP/IP internet protocol suite.