Design a wireless local area network (LAN)

Assignment Brief

You need to design a wireless local area network (LAN) to interconnect two buildings (A and B).

• Block A and B are 1 Km apart.
• The land between these two buildings is owned by a second party that does not allow any kind of cable installation.

Note that:

• Each building has an area of 30 x 20 m2 and is 5 floors high.
• There are 20 offices on each floor.
• The LAN is to provide file and print server facilities and to interconnect all the computers spread over the network.
• There is a database placed in building A.
• There is one PC in each office and several printers are connected to the network also.

The following activities exist on the network during the peak time:

• Each PC downloads 300 Mbytes file every 10 minutes from the database server.
• Each PC updates the database with a 500 Kbytes every 5 minutes.
• Each PC sends a 300 Kbytes file for printing every 30 minutes.
• Messages of 100 Kbytes are transmitted and received every 30 seconds.

In this project, you are supposed to do the following:

1. Give a short introduction to the problem in hand
2. Recommend a type of LAN and justify your recommendation.
3. Determine the average load in bps per user at peak time.
4. Determine where you should put the database, the repeaters, the bridges, the hubs, etc.
5. Draw in detail the LAN you have designed, and give the exact length and the type of the cables required. Calculate the total cost of your LAN by giving details of the costs of all its components.
6. Write a Conclusion
7. Insert all used references

Sample Answer

Wireless LAN Design Report for Interconnecting Building A and B

1. Introduction

This project aims to design a wireless Local Area Network (LAN) to interconnect two buildings, A and B, which are 1 km apart. The main challenge is that no cabling is allowed between the buildings due to land ownership restrictions. Each building has 5 floors, with 20 offices per floor, totalling 100 PCs per building. The network will support database access, printing, and messaging.

2. Recommended Type of LAN

Since physical cabling between buildings is not allowed, the most suitable option is a Wireless LAN (WLAN) using point-to-point Wi-Fi bridge technology, such as IEEE 802.11ac/ax (Wi-Fi 5/6), combined with internal Ethernet LANs inside each building.

• Justification:

  • Wireless point-to-point bridges allow inter-building communication over 1 km.

  • High data rates (up to several Gbps) are achievable using directional antennas.

  • It avoids legal and physical restrictions of laying cables.

  • Scalable and cost-effective for future expansion.

3. Average Network Load per User at Peak Time

Let’s calculate the total load per PC:

Total per PC = 4.24 Mbps

Total for 100 PCs per building ≈ 424 Mbps (per building at peak)

Continued...