Information Technology Reference
In-Depth Information
Internationally, three nonprofit organizations assign and distrib
ute IP numbers:
The American Registration for Internet Numbers (ARIN) as
signs and manages IP addresses for North America, South
America, the Caribbean, and subSaharan Africa.
The Réseaux IP Européns (RIPE) assigns and manages IP ad
dresses for Europe, the Middle East, and the rest of Africa.
The AsiaPacific Network Information Center (APNIC) as
signs and manages IP addresses for Asia and the Pacific basin.
Ethernet Address: The third level of an Internet address is the
Ethernet address, a 48bit address that is built into each actual ma
chine or Ethernet board. Manufacturers register these numbers with
the IEEE Registration Authority, a body within the Institute of
Electrical and Electronics Engineers. When machines are repaired or
when Ethernet cards are replaced, new circuitry has a new Ethernet
address, even though the rest of the computer may be the same. This
underlies the distinction between IP numbers and Ethernet ad
dresses: IP numbers are associated with specific computers and do
not change, whereas Ethernet addresses correspond to Ethernet cir
cuitry and can be attached to any computer. New Ethernet hard
ware warrants new Ethernet addresses, because you are using a
physically different chip or board. However, when you replace the
Ethernet hardwired in your computer, your IP number likely re
mains the same as the designation for your machine within the com
munication network.
addresses related?
When a user wants to send a message, she or he normally desig
nates a domain name, such as cs.utexas.edu. The machine then must
translate this to the Internet IP number and communicate it to the
network. IP numbers in turn must be translated to Ethernet ad
dresses when machines send actual packets of information over spe
cific cables.
The translation between domain and IP numbers, or between IP
numbers and Ethernet addresses, requires your computer to consult
