Correct Answer - Option 3 : Wasted
The correct answer is option 3
In classful addressing, once a network id is assigned to an organization, there is no method available to allocate the unused IP addresses of that network to other organizations. Hence a large part of the available addresses is wasted.
To overcome this wastage CIDR blocking scheme is developed.
In this scheme, a network can be formed in chunks of IP addresses required and can be used by different organizations.
Subnets can also be formed within the network block.
Classful addressing scheme
Class
|
Leading bits (Reserved)
|
Network ID (bits)
|
Number of Networks
|
Host ID (bits)
|
Start Address
|
End Address
|
Class A
|
0
|
8
|
27
|
24
|
0.0.0.0
|
127.255.255.255
|
Class B
|
10
|
16
|
214
|
16
|
128.0.0.0
|
191.255.255.255
|
Class C
|
110
|
24
|
221
|
8
|
192.0.0.0
|
223.255.255.255
|
Class D
|
1110
|
Not Defined
|
Not Defined
|
Not Defined
|
224.0.0.0
|
239.255.255.255
|
Class E
|
1111
|
Not Defined
|
Not Defined
|
Not Defined
|
240.0.0.0
|
255.255.255.255
|