A company has been allocated the address block $10.0.0.0/8$. It must create sub‑nets for three departments with the following host requirements:

- Department B: 2000 hosts
- Department A: 500 hosts
- Department C: 120 hosts

Using variable‑length subnet masking (VLSM) and allocating sub‑nets in order of decreasing host requirement, determine:

1. The network address and CIDR mask for each department.
2. The first usable IP address in Department B's sub‑net.

Present the answer for Department B in the form "network / mask, first usable IP".

Question

A company has been allocated the address block $10.0.0.0/8$. It must create sub‑nets for three departments with the following host requirements:

- Department B: 2000 hosts
- Department A: 500 hosts
- Department C: 120 hosts

Using variable‑length subnet masking (VLSM) and allocating sub‑nets in order of decreasing host requirement, determine:

1. The network address and CIDR mask for each department.
2. The first usable IP address in Department B's sub‑net.

Present the answer for Department B in the form "network / mask, first usable IP".

Accepted Answer

10.0.0.0/21, first usable IP 10.0.0.1

City Guilds Model Questions Vol1 2021 Information Technology Question 32