I manage a network with 36 PC's and 8 G5 Macs running Tiger or later. Recently a managed PowerConnect 3348 switch was installed and configured with 3 VLAN's to keep department traffic seperate. However whenever this switch is plugged into the network it immediately slows the Mac's network speed down to a crawl. I thought it may have been the way the VLAN's were setup so I restored the factory defaults on the PowerConnect and plugged the switch back in and again it slowed the Mac's down. As soon as the switch is removed from the network the Mac's network speed increases. The PC's on the network are not effected by the switch.
Any help would be appreciated.