Transcript IP4

IP4 Address
Scheme
The IP4 addressing scheme uses a
series of 4 bytes. This is called
dotted decimal notation when
viewed in Base 10.
Example: 124.34.77.3
Networking equipment, of course,
sees them in Binary, which looks to
them like this:
1111100 . 100010 . 1001101 . 00000011
1111100 . 100010 . 1001101 . 00000011
Each number is one byte in size
(256 possible numbers from 0 to
255). This gives us 232 possible
address ID numbers for the whole
Internet. Each number is called an
Octet.
We don’t see or type the address
numbers. We type in words or
phrases like www.google.com and
a DNS (Domain Name Server) in
the system translates our words
into the appropriate numbers.
The IP4 addressing scheme is
broken down into groups of
networks based on size, and
distributed using the binary
numbering system to segment the
entire network into these groups.
Since it is binary, every time we cut
a slice, we have to do it exactly in
half, or by 2.
Let’s use a circle to represent the
entire Internet.
The first group of addresses are Class
A. These start with the addresses
0.0.0.0 and go thru 127.255.255.255.
Think of the addresses as working like
an automobile speedometer. It starts
with 0.0.0.0 The next number is
0.0.0.1 then 0.0.0.2 etc. till you get to
0.0.0.255 Then it rolls over to
0.0.1.0 and starts all over again. It all
ends with 255.255.255.255.
Networks are determined by the first
octet.
The first group of addresses are
Class A. These start with the
addresses 0.0.0.0 and go thru
127.255.255.255.
Class A networks 0 – 127 have the
first octet assigned, but are free to
use the other numbers for their
equipment, often called hosts.
113.0.0.0 can be considered:
Network . Host . Host . Host
This gives Class A networks 224
hosts in each network. 2 to the
power of 24 = 16 777 216
113.0.0.0 network includes all
numbers from 113.0.0.0 thru
113.255.255.255.
There are few Class A networks
(128), but each one is huge in size.
Cutting the remainder of the
available numbers in half gives us
our Class B networks. These run
from 128.0.0.0 to 191.255.255.255.
Like the Class A’s, the Class B
networks are also divided into an
assigned network number, and the
remaining host segments, however
the assigned number not only takes
the first octet, but the second one
as well.
103.60.0.0 can be considered:
Network . Network . Host . Host
This gives Class B networks 216
hosts in each network. 2 to the
power of 16 = 65 536
103.60.0.0 includes all numbers
from 103.60.0.0 to 103.60.255.255.
103.61.0.0 is a completely different
Class B network.
Consider the 103.255.0.0 network.
The next Class B network would be
the 104.0.0.0 network, followed by
the 104.1.0.0 network……etc…..
There are a lot more Class B’s than
Class A’s.
There are more Class B networks
(65,536), but each one is smaller
than a Class A in size. 65,536 hosts
in each Class B network.
Class C networks do the process all
over again. Cut the remaining
portion in half, and 12.5% of the
numbers are left.
Class C networks run from
192.0.0.0 to 223.255.255.255.
Class C’s, like Class B’s, take more
octets for their network portion of
their address. This leaves very little
left for the hosts.
213.10.44.0 can be considered:
Network . Network . Network . Host
This gives Class C networks 28 or
256 hosts in each network.
However, there are 2 to the power
of 24 = 16 777 216 networks ! ! !
213.10.44.0 includes all numbers
from 213.10.44.0 to 213.10.44.255.
Network . Network . Network . Host
213.10.45.0 is a completely
different Class C network, as is
213.10.46.0, or even 219.75.89.0.
There are a lot more Class C’s than
Class B’s, but each one is very
small.
The remaining 12.5% is officially
Class D & E, but these addresses
are not issued to users, and are not
discussed here. They are used for
multicasting and experimentation.
If you look closely at binary numbers, you
will see a lot of patterns and numbers that
repeat. Hard drives, RAM, and other PC
components use binary numbers to
determine size. Notice the pattern of the
zeros in the first octet in each network
class.
Since IP4 has limited space for new
network hosts, and the Internet is growing
daily, Scientist and Engineers have
developed a new networking strategy called
IP6. IP6 uses Base 16 or Hexadecimal
instead of base 2 for addressing. When IP6
is fully implemented, every square inch of
the world’s surface can have its own IP
address.