主附vlan一般用於一個網路段的情況，主vlan和子vlan間可以訪問，

而子vlan之間是不能訪問的。

[SwitchA]vlan 2

[SwitchA-vlan2]port ethernet 0/5 to ethernet 0/6

[SwitchA]vlan 3

[SwitchA-vlan3]port ethernet 0/7 to ethernet 0/8

[SwitchA]vlan 5

[SwitchA-vlan5]port ethernet 0/1 to ethernet 0/4

[SwitchA-vlan5]isolate-user-vlan enable ;vlan5是主vlan

[SwitchA-vlan5]quit

[SwitchA]isolate-user-vlan 5 secondary 2,3 ;vlan2,3是子vlan

[SwitchB]vlan 2

[SwitchB-vlan2]port ethernet 0/5 to ethernet 0/6

[SwitchB]vlan 3

[SwitchB-vlan3]port ethernet 0/7 to ethernet 0/8

[SwitchA]vlan 4

[SwitchB-vlan4]port ethernet 0/1 to ethernet 0/4

[SwitchB-vlan4]isolate-user-vlan enable ;vlan4是主vlan

[SwitchB-vlan4]quit

[SwitchB]isolate-user-vlan 4 secondary 2,3 ;vlan2,3是子vlan

這個例子可以借鑑一下