Create SubInterface
This operation creates a new subInterface in the selected physical interface. You can perform this operation by right clicking on the physical interface where you want to create the new subInterface: 
If the physical interface selected is an Ethernet interface, the following form is shown (you have to fill both fields):
If the physical interface selected is a Logical Tunnel interface, the following form is shown (you have to fill both fields):
When all the information has been entered, just click on 'Finish' to perform the operation. If the operation has been successful, the new subInterface will be added in the inventory view.
Modify SubInterface
This operation modifies the data of a subInterface. You can perform this operation by right clicking on the subInterface that you want to modify:
If the subInterface selected is an Ethernet interface, the following form is shown (you cannot modify the identifier, only the VLAN ID):
If the subInterface selected is a Logical Tunnel interface, the following form is shown (you cannot modify the identifier, only the peer unit):
When all the information has been entered, just click on 'Finish' to perform the operation.
Remove SubInterface
This operation removes a subInterface. You can perform this operation by right clicking on the subInterface that you want to remove:
The following window will be opened to confirm that you want to delete the subInterface selected:
If the operation has been successful, the subInterface will be remove from the inventory view.