Description

This article explains the behavior when setting 'no-flow-control' at the PPE overloaded status.

Solution

In the PPE overloaded status, ​packets drop at the pre-classifier, then reports as 'resource error' and 'input packet rejects ' error. However, 'input packet rejects ' error has other contributors such as 'unknown iif' or 'unknown protocol'. Therefore, 'resource error' is the most accurate counter of ppe-overloaded-drop.

  • 'unknown iif' stands for unknown input interface drop caused by RPF check failure.
  • 'unknown protocol' means lookupchip failed in checking the protocol part of the packet.

Example: 

Physical interface: xe-1/0/0, Enabled, Physical link is Up
...
Input errors:
Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 165467470  <--
...
Filter statistics:
Input packet count               616202271
Input packet rejects             165467470  <--

MX#  show precl-eng 1 statistics
stream    Traffic
port      ID       Class             TX pkts               RX pkts Dropped pkts
------  -------  ----------          ---------             --------- --------------
00      1025        RT          0000000000000000      0000000000000000 0000000000000000
00      1026        CTRL        0000000000000023      0000000000000023 0000000000000000
00      1027        BE          0000000661509416      0000000496041946 0000000165467470  <--

This is FAD (functioning as designed).

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