Question

A large organization with a large block address (12.44.184.0/21) is split into one medium size company using the block address (12.44.184.0/22) and two small organizations. If the first small company uses the block (12.44.188.0/23), what is the remaining block that can be used by the second small company? Explain how the datagrams destined for the two small companies can be correctly routed to these companies if their address blocks still are part of the original company.

Answer 1

Answer:

The answer is explained below

Explanation:

The Organization mask is 21 so number of addresses granted to organization are 32 - 21 = 2048 addresses

Now, medium-size company has mask as 22 so number of addresses to medium-size organization are 32 - 22 = 1024 addresses

Each small organization has 32 - 23 = 512 addresses as mask is 23

That implies the range of addresses for each organization

Large Organization = 12.44.184.0/21 - 12.44.191.255/21

Medium organization = 12.44.184.0/22 - 12.44.187.255/22

small Organization 1: 12.44.188.0/23 - 12.44.189.255/23

small Organization 2: 12.44.190.0/23 - 12.44.181.255/23

so now if we have a router then we need to configure it so that when an address is routed correctly.

So router should be installed or configured for forward lookup which are defined in forwarding table

The forwarding table is configured o bases of longest prefix match

So Forward table will be:

00001100 00101100 10111110           small organization1

00001100 00101100 10111111           small organization2

00001100 00101100 1011110           medium-size organization

For each of them we can take an example in the range of its IP address and check this forwarding table  will correctly identify the other inner organizations