With simple Ethernet switches, the entire switch is one Layer 2 broadcast domain that usually equates to one IP subnetwork (Layer 3 broadcast domain). Consider a single VLAN on a VLAN capable Ethernet switch as being equivalent to a simple Ethernet switch. A VLAN is a logical Layer 2 broadcast domain that typically equates to one IP subnetwork. Therefore, multiple VLANs are same as logically separated subnetworks. This arrangement is analogous to multiple switches being physically separated subnetworks. A Layer 3 routing process is required to route between VLANs. This routing process can take place on a connected router or a router module within a Layer 2/Layer 3 Ethernet switch. If no routing process is associated with a VLAN, devices on that VLAN can only communicate with other devices on the same VLAN.