What factors determine whether you plan a two-tier or a three-tier campus LAN topology?
The customer’s cabling requirements usually act as the primary determining factor.
In a multi-building campus, or a very large building, the customer might have a limited number of fibers available to connect the access layer to the core.
You can use modular switches (i.e. Aruba CX 6400 series), IRF, or meshed stacking to create a larger density of edge ports to uplinks.
Sometimes, though, you need a distribution layer (i.e. Aruba CX 6300 series) to aggregate the access layer connections.
The number of ports available at the core will also play a role.
Aruba HPE has core switch offerings, such as the Aruba CX 8325 series, that would easily meet the needs of the largest campuses