| downstream physical unit 1) In SNA, a PU that is located downstream from the host. 2) Cisco IOS software feature that enables a router to function as a PU concentrator for SNA PU 2 nodes. PU concentration at the router simplifies the task of PU definition at the upstream host while providing additional flexibility and mobility for downstream PU devices. This feature is sometimes referred to as DSPU concentration. See also PU and SNA. |