Hierarchical Agent Architecture is proposed to provideonline monitoring services to NoC-based systems. Basedon circuit conditions traced at the run-time, system settingsare monitored adaptively by agents at each architectural level.This monitoring approach partitions various online diagnosticand management services onto hierarchical implementation levelsso as to provide scalability and variability for large-scale NoCdesign. This paper explains the monitoring interaction betweenagent levels, and focuses on system optimization alternativeshandled by different agent levels. It further quantitatively analyzesthe feasibility and design alternatives in monitoring communicationinterconnection upon regular tile-based NoC layout.Though still under intensive research, the proposed architectureis endowed with promising potential for highly-integrated NoCdesign.