How to split an already functioning network into VLANs?

Question

System administration

Good evening/afternoon!

Please advise how to split an already functioning network into VLANs?
There is a network 10.10.0.0/21, ip addresses in this range for everyone (there are 10.10.0.23, and 10.10.1.255 and 10.10.7.221, etc., etc.)
There is a desire to break the network into VLANs, but how I understand that then it will be necessary to divide this network into subnets with masks 23, 24, etc. and configure routing between VLANs so that workers can work.
Is this the only way or is there another way to share?

Answer 1

It is necessary to be defined, what for to break into vlana. This is usually done to be able to control (and limit) traffic between different logical parts of the infrastructure. In this case, of course, it is necessary that data that is not intended for "its" vlan pass through some kind of L3 device, and therefore there must be a non-local route.
In your case - yes, split into smaller ranges.

Answer 2

VLAN is not about IP, it's at a lower level.
https://asp24.ru/novichkam/vlan-dlya-chaynikov/

Answer 3

If the network is one physical, nothing needs to be divided. Just write down the correct address. If the task is not to prohibit access of some network hosts to others. And yes, find and give a good kick to the one who organized it all like that, with addresses.

Answer 4

How many computers are on your subnet?
If there are more than 20-30 PCs, I would definitely begin to sort them into wilans, each department in its own wilan. You need a device that will share traffic between Wealans - a router.