Subnetting and subnet masks in Computer Networks - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the number of hosts in a subnet given the subnet mask bits.

Computer Networks

hosts = (2 ** (32 - [1])) - 2

Drag options to blanks, or click blank then click option'

A24

B26

C16

D30

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to subtract 2 for network and broadcast addresses.

Using the subnet mask bits directly instead of subtracting from 32.

The subnet mask bits represent the network portion. Subtracting from 32 gives the host bits. The number of hosts is 2 to the power of host bits minus 2 (for network and broadcast addresses).

2fill in blank

medium

Complete the code to find the subnet mask in dotted decimal notation from the number of mask bits.

Computer Networks

mask = [[1] for i in range(4)]

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A0

B128

C192

D255

Attempts:

3 left

💡 Hint

Common Mistakes

Using 128 or 192 for all bytes instead of 255 for full bytes.

Confusing mask bits with decimal values.

Each full byte in the subnet mask is 255 in decimal. For example, a /24 mask has three full bytes of 255.

3fill in blank

hard

Fix the error in the code to calculate the number of subnets given the borrowed bits.

Computer Networks

subnets = 2 ** [1]

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Ahost_bits

Bborrowed_bits

Cmask_bits

Dnetwork_bits

Attempts:

3 left

💡 Hint

Common Mistakes

Using host bits or mask bits instead of borrowed bits.

Confusing network bits with borrowed bits.

The number of subnets is 2 raised to the power of the number of bits borrowed from the host portion.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps subnet numbers to their subnet masks in binary.

Computer Networks

subnet_masks = {n: bin(255 << (8 - [1])) for n in range([2])}

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Aborrowed_bits

Bhost_bits

Csubnets

Dmask_bits

Attempts:

3 left

💡 Hint

Common Mistakes

Using host bits or mask bits incorrectly in the shift.

Using mask bits instead of number of subnets in range.

The subnet mask for each subnet is calculated by shifting 255 left by (8 - borrowed_bits). The range is the number of subnets.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps subnet numbers to their broadcast addresses.

Computer Networks

broadcasts = {n: network_base + ([1] * n) + [2] for n in range([3])}

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Asubnet_size

Bsubnet_size - 1

Cnumber_of_subnets

Dhost_bits

Attempts:

3 left

💡 Hint

Common Mistakes

Using host bits instead of subnet size.

Confusing number of subnets with host bits.

The broadcast address for each subnet is calculated by adding the subnet size times the subnet number plus subnet size minus one to the network base. The range is the number of subnets.