MAC addresses are considered physical addresses
because they are assigned to pieces of hardware by
the manufacturer and cannot be reassigned.
IP addresses are assigned by a network administrator
and have meaning only in a TCP/IP network.
These addresses are used solely for routing purposes
and can be reassigned.
Host and network: Rather than assigning numbers
at random to various endpoints (which would be
extremely difficult to manage), every company and
organization listed on the Internet is given a block
of public address numbers to use. This is accomplished
by using a two-part addressing scheme that
identifies a network and host. This two-part
scheme allows the following:
• All the endpoints within a network share the
same network number.
• The remaining bits identify each host within
that network.
In the figure, the first two octets (128.10) identify
a company with an Internet presence (it’s the
address of the router that accesses the Internet).
All computers and servers within the company’s
network share the same network address. The next
two octets identify a specific endpoint (computer,
server, printer, and so on). In this example the
company has 65,536 addresses it can assign (16
bits, or 216). Therefore, all devices in this network
would have an address between 128.10.0.1 and
128.10.255.255.