I have this topology in my network at the company where I work:
Where the only router is the 'main router' (is here where we receive the internet signal from our provider) the others networks points are switches, so today my network is in cascade and I wonder if this is the best topology for my network. If not, what would be ?
EDIT: This is the structure of the company where I work:
With only 17 computers, you really should only be on a single 24 port switch. This is assuming that home run cable pulls aren't out of the question for some reason.
You may not be seeing any bottlenecks right now, but are introducing points of failure, and additional overhead when it comes to troubleshooting. You are also giving employees the ability to plug devices into your network without your knowledge.
As a side note, I once saw a general manager of a hotel plug a WAP into an extra port in his office which went unnoticed for about a week and hotel guests were connecting to it as if it were an open AP. That would be one of my bigger concerns with your setup.
I agree with the other comments that a single switch should suffice, but I think the best answer also depends on the physical lay-out of your office. If you need very long cable runs to accommodate say 5 of your users, you might opt to run a single cable and deploy a desk switch instead.