ASR920 Output Drops

[sean_kndy]

I have an ASR-920-12CZ-A that has a 10GbE ethernet uplink (IP/MPLS BDI) on port TenGigabitEthernet0/0/13.  I then have a few L2 MPLS xconnects/VPLS instances on port TenGigabitEthernet0/0/12 as well as some other IP services on Gi0/0/4.

I am getting about 5-10 output packet drops/sec on the TenGigabitEthernet0/0/12 interface, but I get none on the Gi0/0/4 interface.  There is actually *more* traffic exiting the Gi0/0/4 interface than the TenGigabitEthernet0/0/12 interface.

On port Gi0/0/4 I have an output service-policy applied that sets the queue-limit to 90 percent.  I tried setting this same policy to the TenGigabitEthernet0/0/12, but it doesn't seem to change anything and the output drops continue.

Overall the 10GbE interfaces aren't even 1% utilized.  I do not know why these output buffer drops are occurring, especially on a 10GbE interface.

Any ideas?

[Georg Pauwen]

Hello,

can you post the output of:

show interfaces TenGigabitEthernet0/0/13

[sean_kndy]

glttwy-ofc-bsmnt-asr920-1#sh int te0/0/13
TenGigabitEthernet0/0/13 is up, line protocol is up
  Hardware is 12xGE-2x10GE-FIXED, address is bc26.c744.e10d (bia bc26.c744.e10d)
  Description: ARISTA.ET20
  MTU 9216 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 7/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full Duplex, 10000Mbps, link type is auto, media type is SFP-LR
  output flow-control is unsupported, input flow-control is on
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 9w5d, output 9w5d, output hang never
  Last clearing of "show interface" counters 9w5d
  Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 274748000 bits/sec, 26231 packets/sec
  5 minute output rate 31311000 bits/sec, 12004 packets/sec
     31896981247 packets input, 38230624789470 bytes, 0 no buffer
     Received 9265185 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 17706475 multicast, 0 pause input
     16764577699 packets output, 7925509188462 bytes, 0 underruns
     0 output errors, 0 collisions, 5 interface resets
     25 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

TenGigabitEthernet0/0/12 is up, line protocol is up
  Hardware is 12xGE-2x10GE-FIXED, address is bc26.c744.e10c (bia bc26.c744.e10c)
  Description: ARISTA-ET19
  MTU 9192 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 5/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full Duplex, 10000Mbps, link type is auto, media type is SFP-SR
  output flow-control is unsupported, input flow-control is on
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 3w0d, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/375/0/250 (size/max/drops/flushes); Total output drops: 2394495
  Queueing strategy: Class-based queueing
  Output queue: 0/40 (size/max)
  5 minute input rate 18508000 bits/sec, 8915 packets/sec
  5 minute output rate 232333000 bits/sec, 21250 packets/sec
     5022240356 packets input, 898718036673 bytes, 0 no buffer
     Received 8592153 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 5634817 multicast, 0 pause input
     14694442253 packets output, 20743302735759 bytes, 0 underruns
     0 output errors, 0 collisions, 11 interface resets
     114 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

[Leo Laohoo]

What is behind Te 0/0/12?