How to create a subnet in a network?

Question

Computer networks

Hello. student, moonlighting as an administrator at the enterprise, I am one administrator. there is a task.
Given: building number 1, the Internet comes in, in the closet there is a tp-link archer c50 router and an unmanaged switch, about 6 computers in the building. from the router Ubiquiti bridge to another building number 2 in 300 meters. there is a cabinet and a managed switch, there are no computers. optics will be thrown from building No. 2 into building No. 3 another 300 meters away. in buildings #2 and #3 there will be about 5 specialized computers in total.
question. how to make a subnet for these five computers, which will be randomly distributed over buildings #2 and #3. given that in addition to them, these buildings will also have user computers. but these 5 must be combined into a subnet. I'm just a teapot, please point me in the right direction, what equipment, what, where and why. topic is unfamiliar. thanks in advance

Answer 1

The classic scheme is a separate VLAN on a managed switch for a separate group of computers, it is plugged into a router that can understand the VLAN trunk and route between them. Problem solved.
Managed switches in different buildings are connected by optics, the optics are plugged into the SFP module, which is plugged into the SFP port of the switch / router.
VLAN100 - invisible computers
VLAN200 - all the rest.
TRUNK - a communication channel through which managed switches can forward several networks at once without mixing them together. Please note that all intermediate devices up to the output router must be able to do this in order to be able to bring special computers from 2-3 buildings to the Internet without showing them to anyone.
Difficulty in two places:
1. As a result, all networks should be resolved by TP-LINK, and I only found a mention with a pair of non-standard OPENVRT firmware that vlans can be created and managed on it. Standard firmware only allows you to allocate IP / TV vlanes, which is most likely not enough to solve the current problem.
2. The problem with the wi-fi bridge - if the killers are able to raise the trunk between themselves, then everything is super. If not, the question is how to push two independent locales through a common channel so that they do not intersect.
You will need a managed switch in buildings 1 and 3, plug in
tplink to distribute the Internet to guests, and to resolve all routes and vlans - put a microtic or something else smart enough.
A load from a couple of dozen people will be destroyed by a Mikrotik that is quite compact in power.
Cool option - tsiska. Even used ones with Avito. Just flip through CCNA to understand the whole logic.

Answer 2

Make VLANs on managed switches and bring them together on a router where you will route between your subnets.
Stick optics directly into the switches, and do not spare the money, immediately buy managed ones and with SFP ports (buy transceivers for optics and there will be a touch).
Take for example dlink dgs 1100 series. And don't wait on switches! It's cheaper to go round.