If a Class B network on the internet has a subnet mask of 255.255.248.0, what…

2024

If a Class B network on the internet has a subnet mask of 255.255.248.0, what is the maximum number of hosts per subnet?

  1. A.

    1023

  2. B.

    1022

  3. C.

    1024

  4. D.

    2046

  5. E.

    Question not attempted

Attempted by 155 students.

Show answer & explanation

Correct answer: D

We are given a subnet mask: 255.255.248.0

Let’s analyze it using Class B IP addressing logic.

Step 1: Convert subnet mask to prefix

255.255.248.0 in binary:

255 = 8 bits

255 = 8 bits

248 = 11111000 → 5 bits

0 = 8 bits

So total network bits =

👉 8 + 8 + 5 = 21 bits

So subnet mask = /21

🔍 Step 2: Host bits

IPv4 has 32 bits total:

Host bits = 32 − 21 = 11 bits

🔍 Step 3: Calculate usable hosts

Formula:

2host bits −2

211 − 2=2048−2=2046

⚠️ Important correction

We must be careful:

Since it is a Class B network, default is /16, but mask is /21 → still correct subnet calculation is valid.

However, the question asks maximum hosts per subnet, so we use correct host bits = 11.

👉 So correct answer = 2046

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