HP Rp7410 BSD Sockets Interface Programmer's Guide - Page 19

BSD Sockets Concepts Introduction socket address socket descriptor TCP UDP UNIX Domain Protocol For the internet address family (AF_INET), the socket address consists of the internet address, port address and address family of a socket. The internet and port address combination allows the network to locate a socket. For UNIX Domain (AF_UNIX), the socket address is the directory pathname bound to the socket. A socket descriptor is an HP-UX file descriptor that references a socket instead of an ordinary file. Therefore, it can be used for reading, writing, or most standard file system calls after a BSD Sockets connection is established. System calls that use file descriptors (e.g. read, write, select) can be used with socket descriptors. All BSD Sockets functions use socket descriptors as arguments. Provides the underlying communication support for stream sockets. The Transmission Control Protocol (TCP) is used to implement reliable, sequenced, flow-controlled two-way communication based on byte streams similar to pipes. Refer to the tcp(7p) man page for more information on TCP. Provides the underlying communication support for datagram sockets. The User Datagram Protocol (UDP) is an unreliable protocol. A process receiving messages on a datagram socket could find messages are duplicated, out-of-sequence, or missing. Messages retain their record boundaries and are sent as individually addressed packets. There is no concept of a connection between the communicating sockets. Refer to the udp(7p) man page for more information on UDP. In addition, the UNIX Domain protocol may be used with AF_UNIX sockets for interprocess communication on the same node. Refer to the unix(7p) man page for more information on the UNIX Domain protocol. Chapter 1 19