Allocating each of the 8 subnets

By creating 8 subnets, we basically created 8 different networks that can be allocated through different departments in the organization. These eight sub-networks will be numbered from 0 through 7.

Therefore:
Our source network is: 192.168.1.0/24

Base Net:	11000000. 10101000. 00000001. 00000000 = 192.168.1.0 /24

Rule of RFC 950

When RFC 950 was introduced, almost all routers were classful (RIP-1 Protocol); eventually classless (BGP-4 Protocol) routers were implemented. Because of the classful routers, RFC 950 prohibited the use of subnet 0s and subnet 1s.

But how does a router knows what is a 0s subnet? The answer is it doesn't. It is not an easy task for a classful router using RIP protocol, because RIP does not provide mask or prefix-length information. Therefore the router does not know which is a 0s subnet and which is the entire network. Here is why!

As you can see, they look identical, but the true answer lies in the prefix length or mask. Refer to Figure 8.8. The solution to this 0's problem is the router's entry needed to be updated to include the prefix length in order to recognize which one was the 0's subnet and which one was the entire network.

For the subnet of 1s, the router requires the prefix length to determine whether the incoming package referred to broadcast of subnets 1's or to the broadcast of the entire network.

You should also know that NET Builder software could automate solutions in relation to the 0s and 1s problem. This software allows the network administrator to Forward Subnet-Cast. Other solutions were implemented with the introduction of IGP (Internal Gateway Protocol).