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Cisco Bug: CSCvs11667 - Random bursts of frame timeout drops without egress congestion

Last Modified

May 04, 2020

Products (1)

  • Cisco MDS 9000 Series Multilayer Switches

Known Affected Releases


Description (partial)

The system does not shutdown ports affected by a particular internal ASIC hardware failure. The hardware failure is reported with the following message:
%MODULE-4-MOD_WARNING: Module 10 (Serial number: ...........) reported warning fc1/33-40 due to config register parity error in device DEV_F16_XBAR (device error 0xcd004600)
Also, the error is logged as an exception which can be displayed with the show module internal exceptionlog command:
Sys Error         : config register parity error
Error Description : F16_IAB_INT_SER_PARITY_ERR0

This can result in random bursts of frame timeout drops. If this occurs these counters will be high for the affected ingress port group in the show hardware internal arbiter inst 0 stats command output:
2035   XIF1: req resend msgs rcvd from qasic         0000000046826796 33-40 -
2038   XIF1: grant resend msgs xmtd to qasic         0000000046824677 33-40 -

This is an extremely rare error that can affect all platforms. The particular internal ASIC hardware failure can lead to a partially initialised ASIC, which would not operate as intended.
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