Port priority (lowest number has highest priority) determines the order in which the node will attempt to associate its ports to a spanning tree. If all the ports are assigned the same priority (default: all = 128) then node will prioritize as ETH1, ETH2, ... ETH4. This in order of ascending value of MAC addresses.
Working with MST Instances
In the WebUI, click the Settings tab.
In the left navigation pane, go to Node Interfaces > Bridge > MSTP > MST Instances.
MST Instances
To view an MST Instance's properties:
Click the pop-up icon () next to the entry you want to view.
When you are finished, close the window.
To delete an entry, select the checkbox next to the entry and then click the Delete () icon.