designing mixed 100/1000 Mb lan

Note: if this would be better placed in a different section of this forum for best responses, please advise. Ty I need to figure out how to design and number a mixed 100/1000 MB client environment. The mix: • 28 G3 PPC clients only have 100 MB capable nics. • 15 G4 PPC clients or so have 1000mb nics Resources: • Server G5 tower, 8gb ecc ram, Highpoint RocketRaid 2320 card • enclosure with the share points in Raid 5 • Two independent nic ports • One wireless nic Current design: • Eth 1 feeds all the g3 100 mb capable clients all of which have fixed ip/s • The server is the router numbered 192.168.1.1 255.255.0.0 • Clients are 192.168.1.2 255.255.0.0 and so on. • All clients are wired through cascaded (stupid) switches that terminate with machine 27. • Currently there is no common switch between the 1000 cascade and the 100 cascade. Needs: • All clients 100 and 1000 will need access to the same shares I host. • All clients must have fixed IP/s • I would like to be able to save my EN 0 for my own high bandwidth Internet connection. Main question flow: • If I plug in the eth 1 feed into the first of my 1000gb switches (which are new auto negotiate types) instead of directly into the eth 1 port in the tower: 1. Will that create a loop back? 2. If not, will it slow down my 1000 mb branch 3. If not, should I just pick up numbering the 1000 MB clients 192.168.1.28 and so on. :D