What is L1-L7?

Question

Computer networks

The first time I heard about L2 and L3 in connection with Mikrotik, the fact that Neighbor information is transmitted over L2 and cannot be blocked through a firewall. Further, L4 is an IP connection, and L7 is through a domain.
I would like to read more about them, I tried to look on YouTube, there, on request, L2, L4, etc. gave me something to do with the spine. And in Google I found it only at the request of L4-L7 in English about Load Balancing, but not knowing what it is at all difficult to understand the essence.
Tell me at least on what request to google and where can I read about it?

Answer 1

The L2 firewall in Mikrotik is located in the Bridge - Filters tab