Constructing a Network Addressing Scheme

In all small network environments subnets which are also known as Subnetworks will segmenting into smaller divisions which have their own sort of IP address. In this some bits are used in host portion of an IP address in order to create a subnet address.

Subnetworks:

The networks are often divide into Subnetworks when there are in large networks to provide the addressing flexibility

In the subnet segments are hosts in the network itself. And without the subnet then the network will have a flat topology. Where it has short routing tables and relies on layer 2 MAC addresses to submit the packages. There was no hierarchical structure for the MAC addresses. Growth of the network leads to the use of the network bandwidth becomes less and less efficient.

The following are the disadvantages of the flat network:

• Layer 2 broadcast system is used by all the devices at the same time
• Bandwidth was shared among all the other devices which are on same network
• The lack of boundaries between the devices results in difficult to apply security policies.

The following are the advantages of subnetting a network:

• Performance can be improved when, Overall network traffic was reduced.
• It is easy to manage and map to geographical and functional requirements in the smaller networks.
• Network security can be applied through the interconnections between subnets than the entire network.

In a multiple network environments there is a connection in between Subnetworks and router which are connected to the internet. In the actual details of the internal the network is divided into several multiple Subnetworks which are inconsequential to other IP networks.

The IP addresses must provide an identification for both the network and the hosts of all devices.

Two-Level and Three-Level Addresses: 

In identifying the addresses by IPv4 method and there address classes was developed, a two- level address connection between network and host are seemed sufficient. Mask is associated with all the three address classes A, B, and C they are predefined on it, and it is not required to explicitly configure of the mask.

When the connected networks are increased, it will be clear that inefficient use of the network addresses. And to solve this problem a third level was introduced of addressing, subnets was developed.

Subnet Creation: 

This is created by taking the address bits from all the three cases host portion Class A, Class B, Class C. It is basically assigned by the network administrator. And in the same manner of the IP addresses they must be unique.

The powers of 2 are used in the algorithm to compute the number of subnets.

When the bits are borrowed from the host field, then the additional subnets are being created will be doubled at each certain time and one another is borrowed. While on bit is carried out one bit creates two more possible subnets (2¹=2) and the count goes on when bits are being borrowed.

• When 1 bit is used for the subnet filed then it is resulted in 2 possible subnets (2¹=2).
• When 2 bit is used for the subnet filed then it is resulted in 4 possible subnets (2²=4).
• When 3 bit is used for the subnet filed then it is resulted in 8 possible subnets (2³=8).
• When 4 bit is used for the subnet filed then it is resulted in 16 possible subnets (2⁴=16).
• When 5 bit is used for the subnet filed then it is resulted in 32 possible subnets (2⁵=32).
• When 6 bit is used for the subnet filed then it is resulted in 64 possible subnets (2⁶=64).

And in the general form the formulae can be stated as:

Number of subnets=2^s (where s is bits borrowed by the subnet).