Sure, I can guide you through this. To enable communication between VLANs, we'll need to configure Inter-VLAN routing on your Cisco switch. Here's a step-by-step guide:

1. Create the VLANs: If you haven't already done so, create the VLANs for the 5th and 4th floors.

   Switch#configure terminal
   Switch(config)#vlan <vlan_id>
   Switch(config-vlan)#name <vlan_name>
   Switch(config-vlan)#exit

Replace <vlan_id> with the ID number for your VLAN (for example, 10 for the 5th floor and 20 for the 4th floor) and <vlan_name> with a descriptive name (like "FifthFloor" or "FourthFloor").

2. Assign Ports to VLANs: Assign the ports connected to the computers on the 5th floor to VLAN 10 and those connected to printers on the 4th floor to VLAN 20.

   Switch(config)#interface fastEthernet 0/<port_number>
   Switch(config-if)#switchport mode access
   Switch(config-if)#switchport access vlan <vlan_id>
   Switch(config-if)#exit

3. Configure a Router-on-a-Stick: We'll use one of the router's interfaces to act as a trunk link to the switch, allowing it to understand VLAN tags and route traffic between VLANs.

   On your router:

   Router#configure terminal
   Router(config)#interface gigabitEthernet 0/0.<vlan_id>
   Router(config-subif)#encapsulation dot1Q <vlan_id>
   Router(config-subif)#ip address <ip_address> <subnet_mask>
   Router(config-subif)#exit

Repeat these steps for each VLAN, using appropriate IP addresses within each VLAN's subnet.

4. Configure Trunking on the Switch:

   Switch(config)#interface gigabitEthernet 0/1
   Switch(config-if)#switchport mode trunk
   Switch(config-if)#exit

5. Enable IP Routing on the Switch:

   Switch(config)#ip routing

6. Configure Default Gateway for Devices: The default gateway of the devices on each VLAN should be the IP address of their respective sub-interface on the router.

Please replace <vlan_id>, <port_number>, <ip_address>, and <subnet_mask> with your actual values. Let me know if you need further clarification at any step!

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