Which way next? Layer 3? 1000+ PC's one subnet!

[SW2004]

Hi, I'm hoping someone can help point me in the right direction. I look after a network with approx 1000 PC's, all the PC's are on one site. The network has a 3com Corebuilder 7700 and fibre (gigabit) to every 48 ports. The switches on the edge are layer 2 3com 3300 XM/SM. We only run tcp/ip, there are no other protocols running. We have a Windows 2003 Domain with XP clients throughout. Netbios over TCP/IP is turned off.

My problem is we have a single broadcast domain in one subnet 172.16.*.* which contains all PC's and servers. Performance of the network appears to be very good at the moment; but we are going to be expanding further and adding additional PC's. I know there are limits to a single subnet/broadcast domain.

I'm stuck as to how to segment or manage the expansion of the network. I can start to add layer 3 to the edge but would this solve my problem? How does layer 3 on the edge effect the single Windows domain we have?

I really appreciate your thoughts and comments.

Thanks again.

SW

 

[Saugilsr]

I would definetly be looking into segmenting the network. If only for your own sanity. Adding vlans to your network would solve alot of the problems you would have with a network that size. By grouping computers of the same function you will gain alot more control and expandability.
Im not familiar with that 3com hardware but you probably need to add this functionality in the core. (Maybe theres a module for that 7700.)
I would definetly go this route. I just switched from a 1 subnet medium size network to a multiVlan segmented network and its like a breath of fresh air.