Sockets are the endpoints of a bidirectional communications channel. Sockets may communicate within a process, between processes on the same machine, or between processes on different continents.

    domain  The family of protocols that is used as the transport mechanism. 
            These values are constants such as AF_INET, PF_INET, PF_UNIX, PF_X25, and so on.
    
    type    The type of communications between the two endpoints
            -- SOCK_STREAM for connection-oriented protocols
            -- SOCK_DGRAM for connectionless protocols.

    protocol Typically zero, this may be used to identify a variant of a protocol within a domain and type.

    hostname The identifier of a network interface:
             A string, which can be a host name, a dotted-quad address, or an IPV6 address in colon (and possibly dot) notation
             A string "<broadcast>", which specifies an INADDR_BROADCAST address.
             A zero-length string, which specifies INADDR_ANY, or An Integer, interpreted as a binary address in host byte order.

    port    Each server listens for clients calling on one or more ports.
            A port may be a Fixnum port number, a string containing a port number, or the name of a service.

Server Socket Methods
    s.bind()    This method binds address (hostname, port number pair) to socket.
    s.listen()  This method sets up and start TCP listener.
    s.accept()  This passively accept TCP client connection, waiting until connection arrives (blocking).

Client Socket Methods
    s.connect() This method actively initiates TCP server connection.

General Socket Methods
    s.recv()    This method receives TCP message
    s.send()    This method transmits TCP message
    s.recvfrom()    This method receives UDP message
    s.sendto()  This method transmits UDP message
    s.close()   This method closes socket
    socket.gethostname()    Returns the hostname.