Misal device lu ada 10 port.. nah kalo ga support vlan, itu 10 port cuman bisa 1 segmen yg sama.. misal 192.168.1.1, 192.168.1.2 ............. tapi kalo support vlan, di tiap port bisa diconfigure lagi.. jadi tiap port bisa beda2 segmen :D misal port 1 192.168.1.1, port 2 10.1.10.100, port 3 10.1.