Answer to Question #317712 in Computer Networks for fal

Question

An organization is granted a block of addresses with the beginning address

150.25.0.0/24. The organization needs to have 3 subblocks of addresses to use in its three

subnets: one subblock of 11 addresses, one subblock of 40 addresses, and one subblock of

125 addresses. Design the network and plot it completely with respective subnets, IP range,

Network IDs

Answer 1

There are$2^{32 -24} =256$ addresses in this block. the first address is 14.24.74.0/24; The last address is 14.24.74.255/24.

To satisfy the third requirement ,we assign addresses to sub blocks, starting with the the largest and ending with the smallest one.

1) The number of addresses in the largest sub block ,which requires 120 addresses, is not power of 2, we allocate 128 addresses .The subnet mask for this subnet can be found as 32 -log₂128 =25. The first address in this block is 14.24.74.0/25 ; the last address is 14.24.74.127/25.

2)The number of addresses in the second largest sub block , which requires 60 addresses , is not a power of 2 either, we allocate 64 addresses .The subnet mask for this subnet can be found as $32 - log_{2}64 = 26$ .The first address in this block is 14.24.74.128/26;The last address is 14.24.74.191/26

3) The number of addresses in the smallest sub block ,which requires 10 addresses, is not a power of 2 either we allocate 16 addresses. The subnet mask for this subnet can be found as $32-log_{2}16 = 28.$ The first address in this block is 14.24.74.192/28; The last address is 14.24.74.207/28.