Fujitsu LifeBook UH572 User Manual page 90

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.
The four numbers in an IP address are used in different ways to identify a particular network and a host on that
network. Three regional Internet registries -- ARIN, RIPE NCC and APNIC -- assign Internet addresses from the following
three classes.
Class A - supports 16 million hosts on each of 126 networks
Class B - supports 65,000 hosts on each of 16,000 networks
Class C - supports 254 hosts on each of 2 million networks
The number of unassigned Internet addresses is running out, so a new classless scheme called CIDR is gradually
replacing the system based on classes A, B, and C and is tied to adoption of IPv6.
IRQ
Interrupt Request. An acronym for the hardware signal to the CPU that an external event has occurred which needs
to be processed.
KB
Kilobyte. One thousand bytes.
LCD
Liquid Crystal Display. A type of display which makes images by controlling the orientation of crystals in a crystalline
liquid.
MAC Address
Media Access Control Address. A unique physical address of a network card. For Ethernet, the first three bytes are used
as the vendor code, controlled and assigned by IEEE. The remaining three bytes are controlled by each vendor
(preventing overlap), therefore, every Ethernet card is given a unique physical address in the world, being assigned
with a different address from other cards. For Ethernet, frames are sent and received based on this address.
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