JN0-102: Subnetting Your Internal Network | Juniper Exam Guide

Subnetting Your Internal Network

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Question

You must segment your internal /24 network into a minimum of 12 subnets, each containing a minimum of 12 hosts.

Which network mask do you use?

Answers

Explanations

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A. B. C. D.

C

To segment the internal /24 network into a minimum of 12 subnets, each containing a minimum of 12 hosts, we can use the following process:

Step 1: Determine the number of bits required for subnetting

Since we need to create a minimum of 12 subnets, we need to borrow bits from the host portion of the address to create additional network bits. To determine the number of bits required for subnetting, we can use the following formula:

2^n >= number of subnets

where n is the number of bits required for subnetting.

In this case, we need at least 4 bits for subnetting since:

2^4 = 16 >= 12

Step 2: Determine the number of bits for the host portion

Since the original network mask is /24, it has 8 bits for the network portion and 24-8=16 bits for the host portion. We borrowed 4 bits in Step 1 for subnetting, so we are left with 16-4=12 bits for the host portion.

Step 3: Determine the new subnet mask

The new subnet mask is the combination of the network portion and the subnet portion. In this case, the network portion is 8 bits and the subnet portion is 4 bits. Therefore, the new subnet mask is:

11111111.11111111.11110000.00000000

or /28 in CIDR notation.

Therefore, the answer is option C (/28).