There's no need! 1. How many addresses does your 20M fiber have? 2. Divide Internet cafes according to your address. 3. There are up to 30 machines in each area, and you can't connect any LAN games (unless your Internet cafe has its own server). 4. So your 150 machine can be divided into five areas at most. Each region uses a fixed address. 5. One layer 2 switches with routing function for each fixed address (Harbor, Huawei, D-LINK, price 1500-3000). 6. After the optical fiber comes in, it is divided into five VLANs with VLAN function by a hub (which is better bought), and five addresses are set to divide the bandwidth strategy of each VALN (which can be allocated equally or by region type). 7. Instead of 150 machines in VALN. 8. Each VLAN has at most 30 machines. 9. There is no firewall. If you want, please. It's not necessary. You are not building a website. Your access provider has installed a firewall for you in your local office. If they can't stop you, it's even more hopeless. 10. That's all. If you don't understand, add Q to chat and discuss progress together (7 19407 answer: online consultation)