I was hoping someone could point to a white paper or a best practices document that would give some guidelines as to when it is a good time to break-up a broadcast domain.
I have about 3000 IP nodes on my network and all are in the same subnet. All nodes are plugged into Fast Ethernet switches. 90% of my nodes are Windows NT/2000/XP/NT Server/2000 Server. The other 10% are printers and Unix servers.
My average broadcast traffic is about 43,000 bits/sec (or .043% on a fast ethernet port). 56% of that is ARP, 22% is SMB and the remaining 22% is a variety of different protocols. Everything is IP so I know I won't have to worry about breaking communication between devices that are broadcasting other protocols. These other protocols are active because some systems admins have left network devices at defaults rather than deactivating these protocols. On some systems (mainly print servers) it's impossible to turn off these other protocols.
I already have a good DHCP/DNS system in place to make this transition easier.
All thoughts, advice and stories of past experiences are welcome.