[Techweb] (Internet
Protocol address) The address of a computer attached to a TCP/IP network. Every client and
server station must have a unique IP address. Client workstations have either a permanent
address or one that is dynamically assigned to them each dial-up session. IP addresses are
written as four sets of numbers separated by periods; for example, 204.171.64.2. The
TCP/IP packet uses 32 bits to contain the IP address, which is made up of a network and
host address (netid and hostid). The more bits used for network address, the fewer remain
for hosts. Certain high-order bits identify class types and some numbers are reserved. The
following table shows how the bits are divided. The Class Number is the decimal value of
the high-order eight bits, which identifies the class type.
Class Maximum Maximum bits
in-----
Class Number Networks Hosts NetID
HostID
A 1-127 127 16,777,214 7 24
B 129-191 16,383 65,534 14 16
C 192-223 2,097,151 254 21 8
Class C addresses have been expanded using the CIDR addressing scheme, which uses a
variable network ID instead of the fixed numbers shown above. Network addresses are
supplied to organizations by the InterNIC Registration Service. See CIDR, InterNIC, IPv6,
TCP/IP abc's and IP on Everything. Logical or Physical? : An IP address is somewhat of a
hybrid, which can be thought of as either logical or physical depending on how you view
it. It is a unique number assigned to a node, which makes it seem physical, especially
because there is so much name to IP address resolution going on in the network. Yet, there
is also the Ethernet address that is built into the network adapter. That is indeed
physical, and it does not change, which is very typical of physical device names. However,
since IP addresses can be dynamically assigned, causing the same client workstation to
have a different IP address every day, the IP address seems more like a logical address.
Regardless of what it is, it would make a great debate in a computer science class. See
logical vs physical.
> DNS, domain name
®WNB.274
Class A: A.x.x.x - 126 networks - 16,777,214 hosts
10.x.x.x - private - not valid on Internet
Class B: A.B.x.x - 16,384 networks - 65,534 hosts
169.254.x.x - private - not valid on Internet
Class C: A.B.C.x - 2,097,151 networks - 254 hosts