Description

The intentions of the article is to provide a workaround and log collection plan when end customer reports that interface statistics are reporting incorrect value as compared to what the remote peer graphs are reporting.

Symptoms

On MX80 box customer reported that interfaces statistics are not showing the correct value for input and output traffic rate as compared to what the peer graphs is reporting . There was no report of transit traffic being dropped . In order to verify if the issue is cosmetic or not below outputs can be collected from the box . This will help to to determine the rate being reported on the PFE compared to the rate reported on the CLI outputs . If there isn't any difference 
 
  • Collect show interface <name> extensive from CLI multiple times.
  • Collect monitor interface <name> . Let this command run for sometime .
  • On MX80 box the FPC’s are hosted on the tfeb. To login into the shell fpc’s we will have to login the tfeb0.                                                                                                                                                                          start shell pfe network tfeb0.
  • From the shell determine the impacted interface.
     TAZ-TBB-0(MX80 vty)# show ifd brief   

>>snip<<

151  xe-0/0/2             Ethernet     0x0000000000008000     0  Up<--Taking xe-0/0/2 as example .
 
  • Collect show pfe statistics traffic from tfeb.
      show pfe statistics traffic  
      PFE Traffic statistics:
               632688 packets input  (0 packets/sec)
               545024 packets output (0 packets/sec)
                    0 fabric input   (0 packets/sec)
                    0 fabric output  (0 packets/sec)
  • Collect show pfe statististics ifd brief 151
  • show toe wedge-stats-summary to see if there are any wedge conditions.
  • Also, collect mtip statistics from pfe to see if there are any drops seen or not.
    show mtip-xge summary   
 ID mtip_xge name        FPC PIC ifd                  (ptr)
--- -------------------- --- --- -------------------- --------
  1 mtip_xge.0.0.16        0   0                      503a1248
  2 mtip_xge.0.0.0         0   0 xe-0/0/0             503a1128
  3 mtip_xge.0.0.1         0   0 xe-0/0/1             503a1008
  4 mtip_xge.0.0.2         0   0 xe-0/0/2             503a0f78
  5 mtip_xge.0.0.3         0   0 xe-0/0/3             503a0ee8
  6 mtip_xge.1.2.0         1   2 xe-1/2/0             503a0d38
  7 mtip_xge.1.3.0         1   3 xe-1/3/0             503a0c18

show mtip-xge 4 statistics   
  • Collect tfeb core dumps from the box.

Solution

In order to recover from the issue . We can ask customer to restart the tfeb0 in a MW . This is an intrusive action as it will restart both the FPC’s , hence impacting MW is mandatory .

Modification History

2024-04-29 : Article Created