[c-nsp] Input queue flushes and drops
Rodney Dunn
rodunn at cisco.com
Tue Mar 2 14:49:38 EST 2010
On 3/1/10 7:28 PM, Javi wrote:
> Guys,
>
> I tried increasing the input queue (up to 2048) with no results, input
> flushes keep going up. Users still experiencing really bad VoIP
> performance in that WAN link...
clear the counters and get a few snapshots of sh int stat
with:
term exec prompt time
on...
Compare the process to fast cache counters...
>
> Rodney, I didn't turn off SPD as I'm not sure if that is going to break
> other stuff. This is a production head office main ISR router...
> Any ideas?
Disable it..it will not change anything for the user traffic.
If they are seeing poor voice quality you need to double check the
direction and what class the traffic is matching along with the
corresponding 'sh policy-map int' output for it.
>
>
> Thanks again,
> J
>
>
>
> On Mon, Mar 1, 2010 at 9:13 AM, Javi <cangurobostero at gmail.com
> <mailto:cangurobostero at gmail.com>> wrote:
>
> 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
> <mailto: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 <http://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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