[c-nsp] Input queue flushes and drops

Javi cangurobostero at gmail.com
Sun Feb 28 18:13:16 EST 2010


Thanks guys.

12.4(13r)T, we have a policy-map with 4 classes:

policy-map QOS-OUT
  class DSCP-OUT-RT-VO
   priority 1110 138750
   police cir 1110000 bc 138750 be 138750
     conform-action set-dscp-transmit ef
     exceed-action set-dscp-transmit ef
     violate-action set-dscp-transmit ef
 class DSCP-OUT-D1-RT
    bandwidth percent 7
     random-detect dscp-based
     random-detect dscp 34 25 75 20
     random-detect dscp 36 12 24 20
  service-policy QOS-OUT-D1-RT
 class DSCP-OUT-D2-BA
    bandwidth percent 55
     random-detect dscp-based
     random-detect dscp 18 61 122 20
     random-detect dscp 20 34 68 20
  service-policy QOS-OUT-D2-BA
 class DSCP-OUT-D3-TO
    bandwidth percent 21
     random-detect dscp-based
     random-detect dscp 10 48 96 20
     random-detect dscp 12 31 62 20
  service-policy QOS-OUT-D3-TO
 class DSCP-OUT-RT-VI
    bandwidth percent 6
    queue-limit 30 packets
    police 460000 57500 57500 conform-action set-dscp-transmit af43
exceed-action set-dscp-transmit af21 violate-action set-dscp-transmit
default



And sh int stats:

 GigabitEthernet0/1
          Switching path    Pkts In        Chars In      Pkts Out   Chars
Out
           Processor        311249998 1622425452  311496548 1640497685
           Route cache    910779860  166070169  883679645  1324432555
           Total              1222029858 1788495621 1195176193 2964930240



I'll increase the interface input queue and monitor for a few hours. Cheers,

Javi



On Sun, Feb 28, 2010 at 11:26 AM, Rodney Dunn <rodunn at cisco.com> wrote:

>
>
> On 2/26/10 1:57 AM, Javi in AUS wrote:
>
>> Gents,
>>
>> We have a WAN facing Cisco 3845 which is showing the numbers below on it's
>> Gi0/1 interface:
>>
>>  Input queue: 0/75/9/71805 (size/max/drops/flushes); Total output drops:
>> 714432
>>
>>
> Turn off SPD:
>
> config t
> no spd enable
> end
>
>
>
>
>
>> Of course, these counters are increasing and we have a bunch of users at
>> the
>> other side of the link complaining about poor VoIP performance (they hear
>> us intermittently although we can hear them Ok).
>> CEF is enabled globaly, input queue is set to default (75).
>>
>> GigabitEthernet0/1 is up, line protocol is up
>>   Hardware is BCM1125 Internal MAC, address is 001b.d37d.f8a2 (bia
>> 001b.d37d.f8a2)
>>   Internet address is 10.83.2.17/30
>>   MTU 1500 bytes, BW 20000 Kbit/sec, DLY 100 usec,
>>      reliability 255/255, txload 11/255, rxload 10/255
>>   Encapsulation ARPA, loopback not set
>>   Keepalive set (10 sec)
>>   Full-duplex, 100Mb/s, media type is RJ45
>>   output flow-control is XON, input flow-control is XON
>>   ARP type: ARPA, ARP Timeout 04:00:00
>>   Last input 00:00:00, output 00:00:00, output hang never
>>   Last clearing of "show interface" counters 3w3d
>>   Input queue: 0/75/9/71805 (size/max/drops/flushes); Total output drops:
>> 714432
>>   Queueing strategy: Class-based queueing
>>   Output queue: 0/1000/0 (size/max total/drops)
>>   30 second input rate 848000 bits/sec, 634 packets/sec
>>   30 second output rate 874000 bits/sec, 604 packets/sec
>>      1146444284 packets input, 1913512714 bytes, 0 no buffer
>>      Received 1785 broadcasts, 0 runts, 0 giants, 1 throttles
>>      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>>      0 watchdog, 6993 multicast, 0 pause input
>>      0 input packets with dribble condition detected
>>      1121611018 packets output, 2544901813 bytes, 0 underruns
>>      0 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
>>
>>
>>
> What is your policy doing on that interface for the output drops?
>
> sh policy-map interface gig 0/1
>
> What does 'sh int stat' show...the input queue is only for process switched
> traffic so you need to figure that out?
>
> What code?...12.4(20)T and later you can do an EPC trace on the punt path
> coming in the interface to see what traffic it is.
>
> Or try to catch the packets in 'sh buffers input-interface gig 0/1 packet'
>
>
>
> Should we increase the input queue size to 150,200,250, etc ? Could these
>> flushed/drops be the cause of the poor VoIP performance?
>>
>
> Yeah..set it to the max of 4096.
>
> Rodney
>
>
> Many thanks,
>>
>> P
>> _______________________________________________
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>


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