How many IP subnets are required for a switch with three configured VLANs, assuming all hosts want to use TCP/IP?

In a switched network where multiple VLANs (Virtual Local Area Networks) are configured, each VLAN typically requires its own IP subnet. This is necessary because VLANs are used to segment a network into separate broadcast domains, and each broadcast domain must operate within its own IP addressing schema to avoid IP address collisions and maintain clear routing paths.

Given that there are three configured VLANs, each VLAN serves as a distinct logical network for the hosts connected to it. Therefore, for proper communication and management of traffic within these VLANs using TCP/IP, you must define one individual IP subnet for each VLAN. This ensures that the devices connected to each VLAN can communicate within their own group without interference from devices in other VLANs while also allowing for inter-VLAN routing as needed.

Thus, for three VLANs, you will need exactly three different IP subnets, with each providing the necessary unique addressing for hosts within each VLAN.