What's wireless network "infrastructure mode"? How does the network's mode of operation vary from infrastructure mode? Why cares the network administrator?

What does it imply for a wireless network to be in "infrastructure mode"? What is the network's mode of operation, and how does it vary from infrastructure mode, if it is not infrastructure mode? It's unclear why the manager of the network would be concerned.

How long should a network upgrade take, and when should it be scheduled?

What is a wireless network's "Access Point"? How does it operate in practise?

What does it signify when a wireless network is in "infrastructure mode"? If the network is not operating in infrastructure mode, what mode is it in, and how does it vary from infrastructure mode? Does the network administrator need to be concerned?

In a switched and routed network, how does the department ensure user access?

What is a wireless network built on infrastructure? What mode of operation is the network in when it is not in infrastructure mode? In the context of the network What does this imply, administrator?

In a switched and routed network, how does the department ensure that users always have access?