This document explain in detail path taken by diag packets in asr9000 which validates integrity of the path between NP (network Processor) and RSP CPU.
As a result of failure to receive diagnostics packets will result in PLATFORM-DIAGS-3-PUNT-FABRIC_DATA_PATH_FAILED syslog which indicates some underlaying issue in the data path between NP and RSP CPU.
Author: Mahesh Shirshyad
Technical Leader, Cisco Systems Inc.