IP Addressing Plan for Maximum Subnets and 30 Hosts Each - Cisco Certified Network Associate Exam - 200-125

# How to Develop an IP Addressing Plan for Maximum Subnets and 30 Hosts Each

### 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.

A

To determine the correct answer, we need to do some calculations based on the requirements given in the question.

The address range given is 10.188.31.0/23, which means that the network address is 10.188.31.0 and the subnet mask is 255.255.254.0. This gives us a total of 512 IP addresses (2^9 - 2) in the range.

We need to create subnets with as many as 30 hosts each. This means that we need to find a subnet mask that will give us at least 30 usable IP addresses in each subnet.

To calculate the number of subnets and hosts per subnet that can be created from the given address range, we can use the following formula:

Number of subnets = 2^(n) Number of hosts per subnet = 2^(m) - 2

where n is the number of subnet bits and m is the number of host bits.

Let's try each of the answer choices and see which one meets the requirements:

A. 10.188.31.0/27 Subnet mask is 255.255.255.224 Number of subnets = 2^(5) = 32 Number of hosts per subnet = 2^(3) - 2 = 6 This subnet mask does not meet the requirement of at least 30 hosts per subnet.

B. 10.188.31.0/26 Subnet mask is 255.255.255.192 Number of subnets = 2^(6) = 64 Number of hosts per subnet = 2^(2) - 2 = 2 This subnet mask does not meet the requirement of at least 30 hosts per subnet.

C. 10.188.31.0/29 Subnet mask is 255.255.255.248 Number of subnets = 2^(3) = 8 Number of hosts per subnet = 2^(5) - 2 = 30 This subnet mask meets the requirement of at least 30 hosts per subnet.

D. 10.188.31.0/28 Subnet mask is 255.255.255.240 Number of subnets = 2^(4) = 16 Number of hosts per subnet = 2^(4) - 2 = 14 This subnet mask does not meet the requirement of at least 30 hosts per subnet.

E. 10.188.31.0/25 Subnet mask is 255.255.255.128 Number of subnets = 2^(7) = 128 Number of hosts per subnet = 2^(1) - 2 = 0 This subnet mask does not meet the requirement of at least 30 hosts per subnet.

Therefore, the correct answer is C. 10.188.31.0/29, which allows us to create 8 subnets with up to 30 hosts each.