TCP/IPv6 Migration Guide

Glossary
HP NonStop TCP/IPv6 Migration Guide—524524-004
Glossary-22
unicast address
unicast address. An identifier for a single interface. A packet sent to a unicast address is
delivered to the interface identified by that address.
User Datagram Protocol (UDP). The Internet standard protocol that allows an application
program on one machine to send a datagram to an application program on another
machine. UDP uses the Internet Protocol to deliver datagrams. Conceptually, the
important difference between UDP and IP is that UDP messages include a protocol
port number, allowing the sender to distinguish among multiple destinations
(application programs) on the remote machine. In practice, UDP also includes a
checksum over the data being sent.
valid address. A preferred or deprecated address. A valid address may appear as the
source or destination address of a packet, and the internet routing system is expected
to deliver packets sent to a valid address to their intended recipients.
valid lifetime. The length of time an address remains in the valid state (for example, the
time until invalidation). The valid lifetime must be greater than or equal to the preferred
lifetime. When the valid lifetime expires, the address becomes invalid.
wait mode. In the Guardian operating system, the mode in which the called procedure waits
for the completion of an I/O operation before returning a condition code to the caller.
Compare nowait mode.
WAN. See wide area network (WAN).
WAN manager process. The WAN manager process starts and manages the WAN
subsystem objects including the ConMgr and WANBoot processes.
WAN subsystem. See wide area network (WAN) subsystem.
Warning. In DSM interfaces, a condition encountered in performing a command or other
operation, that can be significant but does not cause the command or operation to fail.
A warning is less serious than an error. Compare error.
well-known port. Any of a set of protocol ports preassigned for specific uses by transport
level protocols (that is, TCP and UDP). Servers follow the well-known port assignments
so clients can locate them. Examples of well-known port numbers include ports
assigned to echo servers, time servers, remote login (TELNET) servers, and file
transfer (FTP) servers.
wide area network (WAN). A network that operates over a larger geographical area than a
local area network (LAN)—typically, an area with a radius greater than one kilometer.
The elements of a WAN may be separated by distances great enough to require
telephone communications. Contrast with local area network (LAN).
wide area network (WAN) subsystem. The Subsystem Control Facility (SCF) subsystem
for configuration and management of WAN objects in G-series RVUs.