Download IP Address

IPv4 Addressing Overview
1
IP Address
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An IP address is a 32-bit sequence of 1s and 0s.
To make the IP address easier to use, the address
is usually written as four decimal numbers
separated by periods.
This way of writing the address is called the dotted
decimal format.
2
Every IP address has two parts:
1.
2.
Network
Host
IP addresses are divided into
classes A,B and C to define
large, medium, and small
networks.
The Class D address class
was created to enable
multicasting.
IETF (The Internet Engineering
Task Force) reserves Class E
addresses for its own
research.
3
Reserved IP Addresses
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Certain host addresses
are reserved and cannot
be assigned to devices on
a network.
An IP address that has
binary 0s in all host bit
positions is reserved for
the network address.
An IP address that has
binary 1s in all host bit
positions is reserved for
the broadcast address.
4
IP Private Addresses
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No two machines that connect to a public network can have
the same IP address because public IP addresses are global
and standardized
Private IP addresses are a solution to the problem of the
collapse of public IP addresses. Addresses that fall within
these ranges are not routed on the Internet backbone:
Connecting a network using private addresses to the Internet
requires the usage of NAT
5
Subnet Mask Address
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Determines which part of an IP address is the
network field and which part is the host field.
Follow these steps to determine the subnet
mask:
 1. Express the subnetwork IP address in
binary form.
 2. Replace the network and subnet portion of
the address with all 1s.
 3. Replace the host portion of the address with
all 0s.
 4. Convert the binary expression back to
dotted-decimal notation.
6
Establishing the Subnet Mask Address

To determine the number of bits to be used, the
network designer needs to calculate how many
hosts the largest subnetwork requires and the
number of subnetworks needed.
7
Subnetting example
8
Variable-Length Subnet Mask - VLSM

VLSM allows you to use more than one subnet
mask within the same network address space subnetting a subnet
S
Subnet Add
0
207.21.24.0/27
1
207.21.24.32/27
2
207.21.24.64/27
3
207.21.24.96/27
Sub-sub
Sub-Subnet Add
4
207.21.24.128/27
Sub 0
207.21.24.192/30
5
207.21.24.160/27
Sub 1
207.21.24.196/30
6
207.21.24.192/27
……..
7
207.21.24.224/27
Sub 5
207.21.24.212/30
Sub 6
207.21.24.216/30
Sub 7
207.21.24.220/30
9
Supernetting
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Using a bitmask to group multiple classful
networks as a single network address.
Same process with route aggregation.
supernetting is most often applied when the
aggregated networks are under common
administrative control.
In class C network addresses, supernetting
can be used so that the addresses appear as
a single large network, or supernet
10
Net #
Net IP
First IP
Last IP
Broadcast IP
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30
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