Glossary

The address format used to interpret addresses specified in socket operations. The internet address family (AF_INET) is supported.

An Interprocess Communication term that refers to the means of labeling a socket so that it is distinguishable from other sockets, and routes to that socket are able to be determined.

A U.S. government research agency that was instrumental in developing and using the original ARPA Services on the ARPANET.

A term used to refer to alternate names for networks, hosts and protocols. This is also an internetwork mailing term that refers an alternate name for a recipient or list of recipients (a mailing list).

The set of services originally developed for use on the ARPANET (i.e., telnet(1)) or distributed with the Berkeley Software Distribution of UNIX, version 4.3 (i.e., rlogin(1)).

The Advanced Research Projects Agency Network.

An Interprocess Communication connection (e.g., a socket) is defined by an association. An association contains the (protocol, local address, local port, remote address, remote port)-tuple. Associations must be unique; duplicate associations on the same system may not exist.

Sockets set up via ioctl with the FIOASYNC option to be notified with a SIGIO signal whenever a change on the socket occurs. Primarily used for sending and receiving data without blocking.

A version of UNIX software released by the University of California at Berkeley.

Establishing the address of a socket which allows other sockets to connect to it or to send data to it.

A communication path created by establishing a connection between sockets.

The host on which a client process is running.

A process that is requesting some service from another process.

A set of properties that describes the characteristics of processes communicating through sockets. Only the Internet domain is supported.

A communications path to send and receive data. A connection is uniquely identified by the pair of sockets at either end of the connection.

A software process that runs continuously and provides services on request.

A socket that maintains record boundaries and treats data as individual messages rather than a stream of bytes. Messages may be sent to and received from many other datagram sockets. Datagram sockets do not support the concept of a connection. Messages could be lost or duplicated and may not arrive in the same sequence sent. Datagram sockets use the User Datagram Protocol.

The military arm of the Advanced Research Projects Agency. DARPA is instrumental in defining standards for ARPA services.

A set of allowable names or values. See also, "Communication domain."

The file transfer protocol that is traditionally used in ARPA networks. The ftp command uses the FTP protocol.

The process of forwarding a mail message to another destination (i.e., another user name, host name or network).

A node that connects two or more networks together and routes packets between those networks.

A node that has primary functions other than switching data for the network.

Called "ISO," this organization created a network model that identifies the seven commonly-used protocol levels for networking.

A four-byte quantity that is distinct from a link-level address and is the network address of a computer node. This address identifies both which network is on the Internet and which host is on the network.

All ARPA networks that are registered with the Network Information Center.

A term used to mean "among different physical networks."

A facility that allows a process to communicate with another process on the same host or on a remote host. IPC provides system calls that access sockets. This facility is distinct from Bell System V IPC. See also, "Sockets."

A six-byte quantity that is distinct from the internet address and is the unique address of the LAN interface card on each LAN.

In IPC, the data sent in one UDP packet. When using sendmail a message is the information unit transferred by mail.

The person who is responsible for managing the networking services on a specific node or host.

A computer system that is attached to or is part of a computer network.

The first host name in each entry in the /etc/hosts file. The official host name cannot be an alias.

A data unit that is transmitted between processes. Also called a "frame."

An Interprocess Communication socket at the other end of a connection.

An address within a host that is used to differentiate between multiple sockets with the same internet address.

A set of conventions for transferring information between computers on a network (e.g., UDP or TCP).

A computer that is accessible through the network or via a gateway.

A port number between 1 and 1023 that is only for super-user use.

A process or host that performs operations that local or remote client hosts request.

A facility that uses Interprocess Communication to perform remote functions for a user (e.g., rlogin(1) or telnet(1)).

The internet address, port address and address family of a socket. The port and internet address combination allows the network to locate a socket.

An HP-UX file descriptor accessed for reading, writing or any standard file system calls after an Interprocess Communication connection is established. All Interprocess Communication system calls use socket descriptors as arguments.

Addressable entities that are at either end of an Interprocess Communication connection. A socket is identified by a socket descriptor. A program can write data to and read data from a socket, just as it writes and reads data to and from files.

A socket that, when connected to another stream socket, passes data as a byte stream (with no record boundaries). Data is guaranteed to arrive in the sequence sent. Stream sockets use the TCP protocol.

A virtual terminal protocol traditionally used on ARPA networks that allows a user to log into a remote host. The telnet command uses the Telnet protocol.

A protocol that provides the underlying communication support for AF_INET stream sockets. TCP is used to implement reliable, sequenced, flow-controlled two-way communication based on a stream of bytes similar to pipes.

A character string containing the UNIX pathname to a UNIX Domain socket.

A protocol providing fast communication between processes executing on the same node and using the AF_UNIX socket address family.

A protocol that provides the underlying communication support for datagram sockets. UDP is an unreliable protocol. A process receiving messages on a datagram socket could find that 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.

A protocol that provides terminal access to interactive services on remote hosts (e.g., telnet(1)).