We have 3 floors, each with a 3Com 3870 48port switch.  There are a few servers and a couple dozen clients that connect to each switch.  The 2nd floor is our "core"  network where the critical servers are located, along where the 1st and 3rd floor switches connect in at.  

Currently we have a flat 192.168.0.0/24 network.  We are running out of IP's and want to start using VLANs, which will allow us to break up the network and hopefully get some perfromance gain.  We would like 1st Floor to be 192.168.10.0/24, 2nd Floor to be 192.168.20.0/24, and 3rd Floor to be 192.168.30.0/24.  Servers will all be on 192.168.100.0/24 (regardless of floor).  

So now my question.  We need to apply the 3.0 update to give us Layer 3 capabilities on the switches (http://www.3com.com/products/software/3870_v3/3780.html).  Would we run RIP v2 on each switch?  Where do we setup our VLANs at?  Doese one switch become a VTP server?  Where do the default gateways get setup (192.168.10.1/192.168.20.1/192.168.30.1/192.168.100.1)?  Lastly, where do we setup the gateway for our internet router?

I am hoping these 3870 swithces will do this task.  We have about 210 devices on the network.  I understand these are desktop class switches and not meant for the core.  We would like to use what we have for now since money is very tight.  Perhaps in another year would get a more beefed up switch for our 2nd Floor.

Sorry for the noobish questions, but this will be my first time deploying a Layer3 switched network with multiple VLANs. I just want to get prepared so we can start gradually migrating computers/devices over to their new VLANs and not break the rest of the network :)

Eric

To keep it simple, accomplish the routing on your 2nd floor switch, by defining the IP addies for those vlans there. Merely have the 1st and 3rd floors VLAN tag up to the third. No need for RIP here as only one switch will actually route...the other will remain at Layer 2 only. VLANs must be set one all three switches, however you will need to define the 1st and 3rd floor VLANs (.10 and .30) on the 2nd floor "core" routing switch with IPs defined for it so it can do direct routing to whatever external gateways you have. I do not believe that 3Com uses VTP, so no worries there.
Hopefully this makes sense and is of some value? :)
-HH