My 2821 routers gi0/1 interface is attached to a 2948G switch. All hosts on the switch belong to the default vlan (vlan1). I want to add three additional subnets. I can add sub interfaces to the gi0/1 router interface but do I need to create new vlans on the switch? If I did not create new vlans on the switch and plugged a host from the new subnet into the switch would it be able to communicate with the rest of the network? My switch is runnning catos 8.3 would you please provide config examples to setup a vlan on this model switch.