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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.
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