Virtual LAN can be designed and visualised by concept of colouring. We logically assign all nodes on same VLAN of same colour, switches forwarding pockets. In VLAN when source and destination ports are on the same switch then there is no need to added any pocket. Switch can keep tracks of
colour of its every ports. But switch-to-switch additional tagged to indicate source. The IEEE 802.1Q is generally used for this pockets-tagging. 32 bit of “colour” tag inserted into Ethernet header after source address and before the type field. The first 16 bits of this field is 0*8100, which become new ethernet types field and which identify frame as tagged.
Double tagging is possible, which allows the Internet service provider to one level of tagging and other level of tagging to the other customers. Virtual LAN allows network administrators to
partition their networks to match the functional and security requirements to the Computer without cables or make major changes in their networks.
This reply was modified 5 years, 5 months ago by kaushlendra.