Corrected VLSM exercises
Exercise VLSM
A multinational company wishes to have an IPv4 addressing plan for the new branch it has created in city X.
The City X branch has 5 departments as follows:
- Human Resources Management (HRM) with 12 personnel;
- Engineering with 23 staff ;
- Information system with 8 personnel;
- Marketing and sales with 50 staff;
- Accounting and auditing with 15 staff.
In total, the City X branch has 108 staff, or a total of 108 client positions.
The network allocated for the branch is 192.168.100.0/24.
While taking into account the evolution of the branch, divide the network into several sub-networks according to the departments.
Solution (Answer key to the VLSM exercise)
Given network: 192.168.100.0/24
Subnetwork requested 5, because there are five departments.
To calculate the subnets (VLSM), we will use our VLSM calculator. This allows us to move quickly.
Data Summary Table:
| Name | Shelter | Number of addresses |
| Human resources management | GRH | 12 |
| Engineering | ING | 23 |
| Information system | SI | 8 |
| Marketing and sales | MV | 50 |
| Accounting and auditing | CA | 15 |
Go to VLSM Calculator, enter your starting network and then give the number of subnets you want to have.
In our case, we need five subnets. Fill in the table with the necessary data. Then calculate.
After the calculations, you will have the results below.
| Name | IP Requested | IP Available | IP Not used | Network address | Slash | Mask | Usable range | Broadcast address | Inverted masks |
| MV | 50 | 62 | 12 | 192.168.100.0 | /26 | 255.255.255.192 | 192.168.100.1 – 192.168.100.62 | 192.168.100.63 | 0.0.0.63 |
| ING | 23 | 30 | 7 | 192.168.100.64 | /27 | 255.255.255.224 | 192.168.100.65 – 192.168.100.94 | 192.168.100.95 | 0.0.0.31 |
| CA | 15 | 30 | 15 | 192.168.100.96 | /27 | 255.255.255.224 | 192.168.100.97 – 192.168.100.126 | 192.168.100.127 | 0.0.0.31 |
| GRH | 12 | 14 | 2 | 192.168.100.128 | /28 | 255.255.255.240 | 192.168.100.129 – 192.168.100.142 | 192.168.100.143 | 0.0.0.15 |
| SI | 8 | 14 | 6 | 192.168.100.144 | /28 | 255.255.255.240 | 192.168.100.145 – 192.168.100.158 | 192.168.100.159 | 0.0.0.15 |
The above result is complete and takes into account everything you will need to write the report and configure your network immediately.
