SONET STS Use the SONET STS subtab to provision the OC-N and MRC-N SONET STS line parameters. Item Description STS # Displays the STS number. Enable IPPM Allows you to enable intermediate path protection monitoring (IPPM). Apply Applies changes made to the fields in the tab. Reset Cancels any changes to the tab and returns the fields to their last-saved settings. Help Displays context-sensitive help.