Doorbell Ringer/Chime: The sounding device that produces a ring, or chime or other type of sound when someone pushes the doorbell button. Some have a different ring/chime pattern depending on if the front or back door button is pushed.
All used ports are associated with VLANs distinct from VLAN 1 and distinct from the black hole VLAN. It is also a good practice to shut down unused switch ports to prevent unauthorized access. A good security practice is to separate management and user data traffic. The management VLAN, which is VLAN 1 by default, should be changed to a separate, distinct VLAN. To communicate remotely with a Cisco switch for management purposes, the switch must have an IP address configured on the management VLAN.
VLAN known as a Virtual LAN is design to make sub LAN network without creating other physical network. The main roll of LAN network is connect multiple machine and merge as one network. LAN network design to communicate with other machine inside network. But in some case if your network is very larger or if your data is very confidential which will not suitable to share with all machine in network then VLAN allows to create virtual Local Area Network within same physical network.