Large corporate network. Examples, templates...?

Question

Computer networks

Hello. I have a thesis on building a large corporate network.
There was an English-language site with examples and ready-made templates from gns3 and cisco pt with really huge topologies, I can’t find it ...
Is there a resource where you can at least see pictures of the topology, where there are examples?
I want to design a three-level hierarchical network model for a large enterprise.
Something like this...

Answer 1

Dive in . You can start with OSPF for example.