The 'switchport trunk allowed vlan except' command is used to allow all VLANs except the one listed. e.g. iF you use
switchport private-vlan trunk allowed vlan except 20, 21, 22, 23
all VLANs except VLANs 20-23 will be allowed on tbe port.
The 'switchport trunk allowed vlan removed' command is used to removed VLANs that were previously allowed e.g. if you had originall used
switchport private-vlan trunk allowed vlan 20-30
all VLANs except VLANs 20-30 would have been allowed at that point.
If you now use:
switchport private-vlan trunk allowed vlan remove 20, 21, 22
the only VLANs allowed now would be 23-30.
Hope that helps - pls rate the post if it does.
Regards,
Paresh.
