Physical Units

Physical units are components that manage and monitor resources such as attached links and adjacent link stations associated with a node. SSCPs indirectly manage these resources through physical units.

Physical units (PUs) exist in subarea and type 2.0 nodes. (In type 2.1 peripheral nodes, the control point performs the functions of a PU.)

A physical unit provides the following functions:
- Receives and acts upon requests from the system services control point (SSCP), such as activating and deactivating links to adjacent nodes
- Manages links and link stations, while accounting for the unique aspects of different link types