[c-nsp] IOS XR: MPLS_PLU_NO_MATCH

[Jason Lixfeld]

So I just had a case where my NMS went bonkers due to an interface dropping a bunch of RX packets.

(all output is post an initial clear counters and clear controller np counters all)

RP/0/RSP0/CPU0:bfr01.151FrontStW01.YYZ#sh int te0/0/0/3 | i "drop|error"
Fri Feb 14 09:49:13.586 EST
     177751373 packets input, 100789584379 bytes, 47000 total input drops
     0 drops for unrecognized upper-level protocol
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     155240851 packets output, 83091994941 bytes, 0 total output drops
     0 output errors, 0 underruns, 0 applique, 0 resets
RP/0/RSP0/CPU0:bfr01.151FrontStW01.YYZ#

Upon further investigation, looks like they were likely dropped due to "MPLS_PLU_NO_MATCH".  I'm basing that on total input drops count from show int roughly lining up with MPLS_PLU_NO_MATCH:

RP/0/RSP0/CPU0:bfr01.151FrontStW01.YYZ#sh controllers np count np4 location 0/0/cpu0 | i "DROP|PUNT"
Fri Feb 14 10:02:56.790 EST
  31  PARSE_INGRESS_DROP_CNT                                 45929           0
  36  MODIFY_INGRESS_DROP_CNT                               363774         181
  40  PARSE_INGRESS_PUNT_CNT                                  3462           2
  41  PARSE_EGRESS_PUNT_CNT                                     10           0
  82  RESOLVE_INGRESS_L3_PUNT_CNT                           832760         432
  83  RESOLVE_INGRESS_IFIB_PUNT_CNT                          75019          40
  84  RESOLVE_INGRESS_L2_PUNT_CNT                              124           0
 848  PUNT_IFIB                                              75019          40
 850  PUNT_ADJ                                                  17           0
 902  PUNT_STATISTICS                                         2885           2
 904  PUNT_DIAGS_RSP_ACT                                        31           0
 906  PUNT_DIAGS_RSP_STBY                                       31           0
 908  NETIO_RP_TO_LC_CPU_PUNT                                   10           0
 942  MPLS_TTL_ONE_PUNT                                          3           0
 944  PUNT_IPV4_ADJ_NULL_RTE                                467023         250
 945  PUNT_IPV4_ADJ_NULL_RTE_EXCD                           363774         181
 986  PUNT_DIAGS_RX_BUFF                                        31           0
RP/0/RSP0/CPU0:bfr01.151FrontStW01.YYZ#sh drops np np4 lo 0/0/cpu0                                  
Fri Feb 14 10:02:58.679 EST

                Node: 0/0/CPU0:
----------------------------------------------------------------

NP 4 Drops:
----------------------------------------------------------------
PARSE_INGRESS_DROP_CNT                                       45929           
MODIFY_INGRESS_DROP_CNT                                      364047          
PARSE_FAB_INJECT_UNKN_CNT                                    10              
MPLS_PLU_NO_MATCH                                            45929           
PUNT_IPV4_ADJ_NULL_RTE_EXCD                                  364047          
----------------------------------------------------------------
RP/0/RSP0/CPU0:bfr01.151FrontStW01.YYZ#

Looking through Xander's https://supportforums.cisco.com/docs/DOC-15552 post, it makes a cryptic reference to "Ingress MPLS frame and outer label lookup miss and not a VCCV frame associated with a pseudo-wire".  Does that mean "Any ingress MPLS frame with an outer label lookup miss except a VCCV frame associated with a pseudowire?"  So that could triggered by a frame carrying an L3VPN packet or any other L2VPN packet?