In my particular case, I'm designing a network for an HQ of an Ice cream company. The building is limited to about 500 drops split up between four IDF So I was debating whether to do a tier 2 or tier 3 setup. This got me thinking about where is the gray area or delineation where to use one vs the other.
I looked into the design guide and while I found interesting information, I didn't find anything that gave numbers, company size, etc, as hints for when to use one or the other. So I just wanted your opinions on the matter, on what would you use in the above example?
There are many factors to consider when doing a network design for a HQ. Certainly size of the company and therefore size of the network are important. You also would consider the possibility of growth of the network, complexity of the network, whether there are parts of the company that need separation in the network from other parts. And I think that you should also consider the skill level of the team that will implement the network, and more importantly the skill level of the team that will support the network.
We do not know much about this company. But I am not hearing anything that suggests that the complexity of a 3 tier network design is needed. Based on what we know so far I believe that a 2 tier would be appropriate.
This link to the Design Guide does not fit your requirement because it is a design for a LAN when WLAN is being "considered".
I looked into the design guide and while I found interesting information,
If you don't know what you're doing, I strongly recommend you get a professional integrator to do it for you. Doing a network for an HQ (an HQ, for goodness sake!) is no laughing matter. It can make-or-break your reputation.
I'm in training, and this is a fictional network of which we practice shopping / creating a BOM, choosing/justifying a design, creating an LLD, etc.