IP Addressing Plan for Maximum Subnets and Hosts

# 10.188.30.0/27

### Question

You are working in a data center environment and are assigned the address range 10.188.31.0/23. You are asked to develop an IP addressing plan to allow the maximum number of subnets with as many as 30 hosts each. Which IP address range meets these requirements?

### Explanations

Click on the arrows to vote for the correct answer

A. B. C. D. E.

D

Each subnet has 30 hosts &lt; 32 = 25 so we need a subnet mask which has at least 5 bit 0s -&gt; /27. Also the question requires the maximum number of subnets

(which minimum the number of hosts- per-subnet) so /27 is the best choice -&gt; .

To create an IP addressing plan to allow the maximum number of subnets with as many as 30 hosts each, we need to subnet the given network 10.188.31.0/23. The subnet mask for this network is /23, which means the first 23 bits of the IP address are fixed, and the remaining 9 bits are available for subnetting.

To determine the number of subnets we can create, we need to calculate the number of subnet bits required. Since we need to create subnets with as many as 30 hosts each, we need to calculate the number of host bits required. To do this, we can use the formula:

2^n >= H + 2

where n is the number of subnet bits, H is the number of hosts required, and 2 is added for the network and broadcast addresses.

Substituting the values, we get:

2^n >= 30 + 2 2^n >= 32

The smallest value of n that satisfies this inequality is n=5. Therefore, we need to borrow 5 bits from the host portion of the IP address for subnetting, leaving 4 bits for hosts.

The new subnet mask would be /28 (23 + 5), which means the first 28 bits of the IP address are fixed, and the remaining 4 bits are available for hosts.

To determine the number of subnets we can create, we can use the formula:

2^n = 2^5 = 32 subnets

Therefore, we can create up to 32 subnets with a /28 subnet mask.

To determine the IP address range for each subnet, we can use the formula:

where Subnet size is the number of IP addresses in each subnet, which is 2^4 = 16.

The network address for the given range is 10.188.31.0, so the first subnet address would be:

Subnet 0: 10.188.31.0/28 (subnet mask 255.255.255.240)

Subnet address = 10.188.31.0 + (0 x 16) = 10.188.31.0

The second subnet address would be:

Subnet 1: 10.188.31.16/28 (subnet mask 255.255.255.240)

Subnet address = 10.188.31.0 + (1 x 16) = 10.188.31.16

Similarly, we can calculate the subnet addresses for the remaining subnets up to subnet 31.

Based on this calculation, the answer that meets the requirements is option B. 10.188.31.0/25, which allows for 128 hosts per subnet and up to 2 subnets. Option A, C, D, and E do not meet the requirement for subnets with 30 hosts each.