Subnet Options for 192.168.0.0/20
Question
A network technician is manually configuring the network settings for a new device and is told the network block is 192.168.0.0/20
Which of the following subnets should the technician use?
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D.C.
The network block 192.168.0.0/20 specifies that the network address is 192.168.0.0 and the subnet mask is 255.255.240.0. To understand this, you need to know how subnet masks work.
A subnet mask is used to divide an IP address into two parts: the network address and the host address. The network address identifies the network that the device is on, while the host address identifies the specific device on that network.
In the case of the network block 192.168.0.0/20, the first 20 bits of the IP address are used for the network address, leaving 12 bits for the host address.
To convert the subnet mask 255.255.240.0 to binary, you can use the following method:
255 = 11111111 in binary 240 = 11110000 in binary
So the subnet mask in binary is:
11111111.11111111.11110000.00000000
This means that the first 20 bits are set to 1 (because they are part of the network address) and the remaining 12 bits are set to 0 (because they are part of the host address).
Now, to answer the question, you need to choose the subnet mask that corresponds to the desired number of subnets. The number of subnets is determined by the number of bits in the subnet mask that are set to 1.
To calculate the number of subnets, you can use the formula:
2^(number of 1 bits in subnet mask)
In the case of the subnet mask 255.255.240.0, there are 20 bits set to 1, so the number of subnets is:
2^20 = 1,048,576
So the network technician can choose any subnet mask that has at least 20 bits set to 1, but no more than 32 bits set to 1 (because an IP address has 32 bits).
Let's check each of the answers:
A. 255.255.128.0: This subnet mask has 9 bits set to 1, which would allow for 512 subnets. This is not enough, so this answer is incorrect.
B. 255.255.192.0: This subnet mask has 10 bits set to 1, which would allow for 1,024 subnets. This is more than enough, so this answer is correct.
C. 255.255.240.0: This subnet mask is already given in the question and has 20 bits set to 1, which allows for 1,048,576 subnets. This is also more than enough, so this answer is correct.
D. 255.255.248.0: This subnet mask has 13 bits set to 1, which would allow for 8 subnets. This is not enough, so this answer is incorrect.
Therefore, the correct answers are B and C.
