Cisco Support Community
Community Member

NX-OS ingress traffic disappeared, trying to find out where it went

Hey all,


Recently we experienced a large ingress spike, on the order of 7Gb/s at our borders.  Tracing it back through our network, we see it passing our NX-OS 7k's, into a 5548 pair, and finally stopping at one of the fiber uplinks of a 2248.  Basically, we are able to see the traffic flowing toward the access layer, but once it gets there, no access layer ports show any ingress spikes.

I've looked over all of our traffic graphs during this time period, and I'm stumped.  My only thought left would be a possible buffer overflow occurred, and packets ended up getting dropped.  I'm still new to the NX-OS game, so I was hoping someone may know how to check the queuing output for possible buffer issues, queuing drops, and so on.

I found 'show queuing interface', but I'm having trouble deciphering the output.  I'm concerned about the xoff counters, and was wondering if the output below my indicate that some flow-control was being used during this ingress spike period.  Here is one such output on the last port we are able to see the traffic taking:

dswitch3# show queuing interface ethernet 1/4 detail
Ethernet1/4 queuing information:
  TX Queuing
    qos-group  sched-type  oper-bandwidth
        0       WRR            100

  RX Queuing
    qos-group 0
    q-size: 470080, HW MTU: 1500 (1500 configured)
    drop-type: drop, xon: 0, xoff: 470080
        Pkts received over the port             : 3946459590
        Ucast pkts sent to the cross-bar        : 2961741530
        Mcast pkts sent to the cross-bar        : 984718150
        Ucast pkts received from the cross-bar  : 1626945682
        Pkts sent to the port                   : 1798052191
        Pkts discarded on ingress               : 0
        Per-priority-pause status               : Rx (Inactive), Tx (Inactive)

  Total Multicast crossbar statistics:
    Mcast pkts received from the cross-bar      : 171106425

  FEX interface info:
    FEX Drop Class Buffer Size: 316160

  Total FEX interface statistics:
    FEX Uplink Interface Rx Drops: 0

As far as I can tell, we have not modified any class-maps or policy-maps on this switch, and I would assume the same about our 2248 FEX switches.

Everyone's tags (1)
CreatePlease to create content