Designing applications with address families

These scenarios illustrate how to design applications with each of the socket address families, such as AF_INET address family, AF_INET6 address family, AF_UNIX address family, and AF_UNIX_CCSID address family.

Using AF_INET address family
AF_INET address family sockets can be either connection-oriented (type SOCK_STREAM) or connectionless (type SOCK_DGRAM). Connection-oriented AF_INET sockets use Transmission Control Protocol (TCP) as the transport protocol. Connectionless AF_INET sockets use User Datagram Protocol (UDP) as the transport protocol.
Using AF_INET6 address family
AF_INET6 sockets provide support for Internet Protocol version 6 (IPv6) 128 bit (16 byte) address structures. Programmers can write applications using the AF_INET6 address family to accept client requests from either IPv4 or IPv6 nodes, or from IPv6 nodes only.
Using AF_UNIX address family
Sockets that use the AF_UNIX or AF_UNIX_CCSID address family can be connection-oriented (type SOCK_STREAM) or connectionless (type SOCK_DGRAM).
Using AF_UNIX_CCSID address family
AF_UNIX_CCSID address family sockets have the same specifications as AF_UNIX address family sockets. AF_UNIX_CCSID address family sockets can be connection-oriented or connectionless. They can provide communication on the same system.

Parent topic: Basic socket design