- The loopback port has to be a unused port on the switch. Nothing needs to be be plugged into this port and all VLAN configuration will be removed.
- A loopback port is needed only when there are multiple subscriber VLANs added into a network VLAN that share the same port. The loopback port only needs to be added each additional subscriber VLAN sharing the same port. For example, subscriber VLAN1 and VLAN2 both have port 1 added to them. Subscriber VLAN2 will need a dedicated loopback port.
- Each subscriber VLAN that will need a loopback port will require a UNIQUE port. For example, Subscriber VLAN1, VLAN2 and VLAN3 all have port 1 added into it. Subscriber VLAN2 will require a loopback port of 48 and subscriber VLAN3 will require a loopback port of 47. As mentioned in the above bullet both of these ports will be unusable.