An ISP has the IP addresses in the range of 1491640018 Suppo

An ISP has the IP addresses in the range of 149.164.0.0/18. Suppose that four organizations, A, B, C, and D, request 8000, 4000, 2000, and 2000 IP addresses, respectively, and in that order. For each of these, give the first IP address assigned, the last IP address assigned, and the mask in the w.x.y.z/s notation.

Solution

We cannot be done with that IP 198.16.0.0 because 198 is a class C IP address

Class C (deafault) address has a subnet mask of 255.255.255.0. So that you can only take from the presented host bits to expand the network portion, the biggest number of hosts per subnet for a class C address is 255, through 254 hosts per network with no subnetting - if you subnetted the class C address, you would ending up through:

We can use a class B address of 98.16.0.0, in which case - assume that you are not going to use VLSM, you could use:

Network: 98.16.0.0/19

Initial Valid IP: 98.16.0.1/19

Final Valid IP: 98.16.31.254/19

Broadcast: 98.16.31.255/19

Network: 98.16.32.0/19

Initial Valid IP: 98.16.32.1/19

Final Valid IP: 98.16.63.254/19

Broadcast: 98.16.63.255/19

Network: 98.16.64.0/19

Initial Valid IP: 98.16.64.1/19

Final Valid IP: 98.16.95.254/19

Broadcast: 98.16.95.255/19

Network: 98.16.96.0/19

Initial Valid IP: 98.16.96.1/19

Final Valid IP: 98.16.127.254/19

Broadcast: 98.16.127.255/19