What are two characteristics of the campus architecture hierarchy tiers? (Choose two)

A.
A network may have four or more physical tiers of switches if necessary

B.
There are absolute rules for how a campus network is physically built

C.
Having three physical tiers is a strict requirement

D.
The network can have two tiers of switches combined into one

E.
Each layer in the hierarchy can perform the functions of the other layers

Explanation: