Chronic Output Drops/Discards

I am curious to know the origin of what seems to be a case Discards on
every active interface in a 3750x. It is explained this happens when switch
can't handle ingress traffic. This is confusing as I have all interfaces
(minus AP's) negotiating auto 10 100:

GigabitEthernet1/0/3 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is f0f7.55dc.0403 (bia
f0f7.55dc.0403)
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 723
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 2000 bits/sec, 3 packets/sec
     1144144 packets input, 151203489 bytes, 0 no buffer
     Received 144964 broadcasts (133217 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 133217 multicast, 0 pause input
     0 input packets with dribble condition detected
     15358132 packets output, 2075639952 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     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

Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize
 OutDiscards
Gi1/0/3 0 0 0 0 0
   723

!
interface GigabitEthernet1/0/3
--omitted
 speed auto 10 100
--omitted
end

GigabitEthernet1/0/3 (All statistics are in packets)

  dscp: incoming
-------------------------------

  0 - 4 : 1130360 0 0 0 0
  5 - 9 : 0 0 0 0 0
 10 - 14 : 0 0 0 0 0
 15 - 19 : 0 0 0 0 0
 20 - 24 : 0 0 0 0 0
 25 - 29 : 0 0 0 0 0
 30 - 34 : 0 0 0 0 0
 35 - 39 : 0 0 0 0 0
 40 - 44 : 0 0 0 0 0
 45 - 49 : 0 0 0 0 0
 50 - 54 : 0 0 0 0 0
 55 - 59 : 0 0 0 0 0
 60 - 64 : 0 0 0 0
  dscp: outgoing
-------------------------------

  0 - 4 : 1747393 0 0 0 2
  5 - 9 : 0 1264 0 0 0
 10 - 14 : 0 0 0 0 0
 15 - 19 : 0 0 0 0 0
 20 - 24 : 0 0 0 0 0
 25 - 29 : 0 0 0 0 0
 30 - 34 : 0 0 0 0 0
 35 - 39 : 0 0 0 0 0
 40 - 44 : 0 0 0 0 0
 45 - 49 : 0 28 0 2215308 0
 50 - 54 : 0 0 0 0 0
 55 - 59 : 0 0 0 0 0
 60 - 64 : 0 0 0 0
  cos: incoming
-------------------------------

  0 - 4 : 1144159 0 0 0 0
  5 - 7 : 0 0 0
  cos: outgoing
-------------------------------

  0 - 4 : 5961065 0 77 0 0
  5 - 7 : 1208 4632126 4764117
  output queues enqueued:
 queue: threshold1 threshold2 threshold3
-----------------------------------------------
 queue 0: 2 0 0
 queue 1: 6111330 699091 4764284
 queue 2: 0 0 0
 queue 3: 0 0 3784269

  output queues dropped:
 queue: threshold1 threshold2 threshold3
-----------------------------------------------
 queue 0: 0 0 0
 queue 1: 0 0 0
 queue 2: 0 0 0
 queue 3: 0 0 723

Policer: Inprofile: 0 OutofProfile: 0

I guess my question is... how could there be discards coming if 3750x has
gig interfaces w/3 asics that all have 10gb combined to make a 30gb
backplane????

Any insight is appreciated. Currently no mls QoS is on LAN. Also wondering
if you think enabling QoS will at least allow limit packet loss to
prioritized traffic?

Thanks in advance for any insight.

Regards,

Marc

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Received on Thu Jul 05 2012 - 11:12:59 ART