We have put in service a catalyst 3850-12XS running ver 03.07.03E and we have noted that in certain ports, there is high output drops. Auto QOS is configured on this switch and we have tried removing the qos config on the ports having problem but it didn't change anything. From a performance point of view, at the moment the switch is running without problems... there is no network outage.
TenGigabitEthernet1/0/1 is up, line protocol is up (connected)
Hardware is Ten Gigabit Ethernet, address is 00cc.fc68.f681 (bia 00cc.fc68.f681)
Description: VLAN 599 XXXXXXXX
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 128/255, txload 16/255, rxload 10/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, link type is auto, media type is 10/100/1000BaseTX SFP
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:19, output never, output hang never
Last clearing of "show interface" counters 10:12:51
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 249067352
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
5 minute input rate 41672000 bits/sec, 6894 packets/sec
5 minute output rate 65358000 bits/sec, 8267 packets/sec
69357766 packets input, 54278801831 bytes, 0 no buffer
Received 1362 broadcasts (1226 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 1226 multicast, 0 pause input
0 input packets with dribble condition detected
97533479 packets output, 108964531997 bytes, 0 underruns
249067352 output errors, 0 collisions, 0 interface resets
0 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
As you can see from the ping below that's sending traffic through the link described above, there seem to be no connectivity issues apart from the fact that the output drops counter indicate something completely different.
XXXXXX#ping 4.2.2.1 repeat 1000 size 100
Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 4.2.2.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (1000/1000), round-trip min/avg/max = 10/14/30 ms
Could this be a bug ?
