My second question is rather simple: do we need a manageable switch? What can be managed with it?
Yes, a switch will improve network performance, provided that the server's Ethernet cards can operate at 100M bit/sec. If not, then you will have to upgrade them as they will become the bottleneck once you add switches to your network.
You probably don't need to spend more to get a manageable switch. What you can manage is the ability to track down problems on each of the ports, to turn individual ports on and off and to set up virtual LANs across a collection of ports. Given the size of your network, this is probably overkill.
Switches used to cost a lot of money but are now very competitive, and it
makes more sense to buy one than to buy just a plain 100M bit/sec hub.
This was first published in April 2002