Domain Description 
AF_INET IPv4 Internet based protocols. TCP and UDP are common protocols of this protocol family.  
AF_UNIX Local communication protocol family. High efficiency and low overhead make it a great form of IPC (Interprocess Communication).  

The type parameter selects the type of communication to be used by the socket. 

Table 2. Available socket types

Type Description 
SOCK_STREAM Provides sequenced, reliable, full-duplex, connection-based byte streams. An out-of-band data transmission mechanism may be supported. The TCP protocol is based on this socket type.  
SOCK_DGRAM Supports datagrams (connectionless, unreliable messages of a fixed maximum length). The UDP protocol is based on this socket type.  
SOCK_SEQPACKET Provides a sequenced, reliable, two-way connection-based data transmission path for datagrams of fixed maximum length; a consumer is required to read an entire packet with each read call.  
SOCK_RAW Provides raw network protocol access. This special type of socket can be used to manually construct any type of protocol. A common use for this socket type is to perform ICMP requests (like ping, traceroute, etc).  
SOCK_RDM Provides a reliable datagram layer that does not guarantee ordering. This is most likely not implemented on your operating system.