I have an assignment to make this network more efficient. The existing network consist of 30 hosts, 5 application servers, and a single domain server, designed around a single switch atatched to a variety of hubs.What changes would you recommend.
Before you can know how to make it more efficient you need to understand how it is working now and measure any problems or bottlenecks.
For example, is the switch 10 or 100, or 1,000 mbps? Does it have faster links to the servers, or are the servers connected with multiple links? Are the servers properly sized, with enough memory and CPU resources?
If you mean "hubs" as in HUBS and not other switches, first thing you do is get rid of those, they will slow downanything attached to them. You can't ask for changes without giving detailed info as to how things are attached, what cabeling is used between the components, if network testing was already done to find issues, what hardware the computers and servers have, etc...