TCP/IPv6 Migration Guide

Glossary
HP NonStop TCP/IPv6 Migration Guide—524524-004
Glossary-11
International Telecommunications Union
Telecommunications (ITU-T)
International Telecommunications Union Telecommunications (ITU-T). An international
body of member countries whose task is to define recommendations and standards
relating to the international telecommunications industry. The fundamental standards
for ATM have been defined and published by the ITU-T (previously CCITT).
Internet. Physically, a collection of packet switching networks interconnected by gateways,
along with protocols that allow them to function logically as a single, large, virtual
network. When written in uppercase, INTERNET refers specifically to the DARPA
Internet and the TCP/IP protocols it uses.
Internet address. The 32-bit address assigned to hosts that want to participate in the
Internet using TCP/IP. Internet addresses are the abstraction of physical hardware
addresses, just as the Internet is an abstraction of physical networks. Actually
assigned to the interconnection of a host to a physical network, an Internet address
consists of a network portion and a host portion. The partition makes routing efficient.
Internet Control Message Protocol (ICMP). An integral part of the Internet Protocol (IP)
that handles error and control messages. Specifically, gateways and hosts use ICMP to
send reports of problems about datagrams back to the original source that sent the
datagram. ICMP also includes an echo request/reply used to test whether a destination
is reachable and responding.
Internet Engineering Note (IEN). A series of notes developed in parallel to RFCs and
available across the Internet from the INIC. IENs contain many of the early theories on
the Internet.
Internet Protocol. The Internet standard protocol that defines the Internet datagram as the
unit of information passed across the Internet, and that provides the basis for the
Internet, connectionless, best-effort, packet-delivery service.
interoperability. The ability of software and hardware on multiple machines from multiple
vendors to communicate meaningfully.
invalid address. An address that is not assigned to any interface. A valid address becomes
invalid when its valid lifetime expires. Invalid addresses should not appear as the
destination or source address of a packet. In the former case, the Internet routing
system cannot deliver the packet; in the latter case, the recipient of the packet cannot
respond to it.
IOP. Input/output process. An input/output process (IOP) is a privileged process, residing in
a fault-tolerant system processor, which provides an application access to a
communications line.
IP. See Internet Protocol.
IP datagram. The basic unit of information passed across the Internet. An IP datagram is to
the Internet as a hardware packet is to a physical network. It contains source and
destination addresses, along with data.