Question : Cisco Network Core v. Distribution layer

In the attached picture, you'll see what "may" be a classic core and distribution network.  However, I have some issues or questions about it.

The most important question is, in a very technical internal sense, what would I look for to know that the distribution switches are distribution switches and the core switches are core switches?  I do understand that connectivity should determine this, first, but the connectivity that I have seen is questionable.  So, I would like to know what I would need to see in the config files for each unit that would make me say, yeah that one is core or no that one is distribution.

A second question would be, is it typical to collapse the distribution layer and have both the data center and the campus be in a single distribution layer?  Why would you not want to do that?

Thanks for your help....Rick

Attachments:

Core.png (29 KB) (File Type Details) 

Picture of questioned core/distribution layers

Answer : Cisco Network Core v. Distribution layer

Distribution will have routes, router protocols, vlans for users....
Core will have only vlans for interconection (with no IP, except from self switch IPs)