Trunk Utilization (ONS 15454 SDH only) Use the Trunk Utilization subtab to view the trunk resources used by spanning tree circuits. Item Description Circuit Name Displays the name of the Ethernet circuit. Size Displays the Ethernet circuit size. Slot/Port/VC4 Displays the Ethernet trunk slot, port, and VC4. Prev Displays the utilization percentage for the previous interval period. Prev-1 to Prev-59 Displays the utilization percentage for the previous 59 interval periods. Interval Displays the interval time. Choices are—1 min, 15 min, 1 hour, or 1 day. Refresh Refreshes the Trunk Utilization fields. Help Displays context-sensitive help.