Glossary
EN/LZT 108 6492 R1 95 (98)
April 2003
IGMP
Short for Internet Group Management Protocol, the standard for IP multicasting in the
Internet.
It's used to establish host memberships in particular multicast groups on a single
network. The mechanisms of the protocol allow a host to inform its local router, using
Host Membership Reports, that it wants to receive messages addressed to a specific
multicast group.
IP address
An identifier for a computer or device on a TCP/IP network. Networks using the
TCP/IP protocol route messages based on the IP address of the destination. The format
of an IP address is a 32-bit numeric address written as four numbers separated by
periods. Each number can be zero to 255. For example, 1.160.10.240 could be an IP
address.
Within an isolated network, you can assign IP addresses at random as long as each one
is unique. However, connecting a private network to the Internet requires using
registered IP addresses (called Internet addresses) to avoid duplicates.
ISDN
Abbreviation of Integrated Services Digital Network, an international communications
standard for sending voice, video, and data over digital telephone lines or normal
telephone wires.
ISP
Short for Internet Service Provider, a company that provides access to the Internet.
LAN
Short for Local Area Network, a computer network that spans a relatively small area.
Most LANs are confined to a single building or group of buildings and connect
workstations and personal computers. However, one LAN can be connected to other
LANs over any distance via telephone lines and radio waves. A system of LANs
connected in this way is called a wide-area network (WAN).
There are many different types of LANs Ethernets being the most common for PCs.
LED
Abbreviation of Light Emitting Diode, a type of control lamp on devices that indicates
the status of a device.
NAT
Short for Network Address Translation, an Internet standard that enables a local-area
network (LAN) to use one set of IP addresses for internal traffic and a second set of
addresses for external traffic. A NAT box located where the LAN meets the Internet
makes all necessary IP address translations.
NIC
Short for Network Interface Card, an expansion board you insert into a computer so
the computer can be connected to a network. Most NICs are designed for a particular
type of network, protocol, and media, although some can serve multiple networks.
Packet
A piece of a message transmitted over a packet-switching network. One of the key
features of a packet is that it contains the destination address in addition to the data.
