Question

Explain with an example a scenario where both the class full and classless IP addressing scheme can be used to configure the IP address for the network.

Answer 1

IP Address:

An IP address is an identifier or label used to identify a machine on the internet or a particular network. Each of the devices on the internet must have an IP address for identification.

IPv4 is the first version of Internet Protocol that uses a 32-bit address and this protocol is most widely used.

Total number of IP address supported by IPv4 = 2³²

The netmask and subnet mask is used to divide the IP address as given below:

The netmask is a sequence of '1' followed by a sequence of '0' and it is used to divide an IP address into multiple subnets.

The subnet mask is a sequence of '1' followed by a sequence of '0' and it is used to separate a big network into smaller multiple networks.

The subnet mask is used to separate the IP address into a network address and host address.

It is made by setting '1' to all network bits and '0' to all host bits. In a network, the first and last IP addresses are used for the special purpose and the remaining addresses are used as a host address.

Classful Addressing:

In classful addressing, an IP address is related to a class and we need to purchase a class of the IP addresses as per the requirement.

Address class:

Class A:

The range of the first octet: 0 to 127

Subnet mask = 255.0.0.0

Class B:

First octet range: 128 to 191

Subnet mask = 255.255.0.0

Class C:

First octet range: 192 to 223

Subnet mask = 255.255.255.0

Class D:

First octet range: 224 to 239

This class is reserved for multicasting, so there is no need for the subnet mask.

Class E:

First octet range: 240 to 254

This class is reserved for experimental purposes, so there is no need for the subnet mask.

For example:

If we required to purchase 255 IP addresses, then we must purchase class C because in class C we can use 255 addresses for each of the network ids.

But if an organization needs 260 addresses, then he must go to class B and there is a lot of wastage of the IP addresses. This problem was resolve by a classless addressing scheme.

Classless addressing:

The previous system of allocating the IP address that was based on classes like class A, class B, etc. and classless addressing is based on variable-length subnet masking.

For example:

Let us suppose the given IP address is:

193.62.83.0/23

The netmask in binary representation will be:

11111111 11111111 11111110 00000000

The netmask in decimal representation will be:

255 255 254 0

Here, 23 bits are used for network id, and the last 9 bits are used for host id.

Total number of IP addresses will be = 2⁹ = 512

In a network, the first and last IP addresses are used for the special purpose and the remaining addresses are used as a host address.

The total number of the host in this network will be = 512 - 2 = 510

So, there is less wastage of the IP addresses in the classless addressing scheme.