How many users are there?
For a good deployment you need
Firewall that is plugged to the internet
Then on the firewall on his internal port you plug in a Switch Layer 3
And then you plug in the Distribution or access switches(depending on how big is your bussiness) guess is small so you could plug the IAPs to the Acess switches...
How small is your bussiness?
At least i got a deployment with instants on a small bussiness of 40 users
I got a Fortigate 80C which is nice for Webfilter, firewalll, app control ETC its all in it
Plugged to that i got a small core switch of 10 ports(10/100/1000) an alcatel POE, which where im pluggin the uplink of the other access switch which is a 48 port switch and the servers
I plugged the Instant to the core switch
I got fortigate FSSO integrated with AD, also got the Instant integrated with an NPS server 802.1x (with roles)and also the swtiches with 802.1x(with something similar than role works the same)... all the managment with nps
Everything is integrated with AD so to manage everything he just need to change groups on the AD...
ITs a small bussiness with all the securiy and centralized managment on the AD groups. Its interesting this deployment and they are happy with it
Anyways this is just an example with the brands i manage,
You could change the Firewall brand to another but if you gonna buy a UTM firewall check the Gartner quadrant! fortinet is the one leadering it. On switches you can change them with another good brand! could be cisco but it will be more expensive, or the guys on the forum can advice you on this... You could use a Aruba Switch also used as stand alone and do all this... and if you buy a controller later you can integrate EVERYTHING with NPS and all the rules will be in single point....
Just imaging that the role you using apply for wired users, wireless and vpn clients.... but you need the controller for that.
Anyways the basic is
Firewall--Switch core---Layer 2 switches
And of course vlans and all that...
PD:
If i cannot mention other brands in my post please just advice me moderators ill edit the message and ill not mention other brands again