Packet drops in HQF class !

Unanswered Question
Jan 24th, 2012
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Hello!


The following part of policy-map shows  there are dropped packet in class ( WAN_DSCP_CS1 drop rate 3000 bps )

The actually rate is lowest as target shape rate and the no-buffer drops counter is zero!


The full config contains appr. 100 branch-class and every branch-class call the WAN_OUTPUT_V.1 policy.


We applied the service-policy on GigabitEthernet 0/3.



The hardware is 7206VXR-G1 the softver is 12.4.20.T advanced ip services


How it is possible to find it how the router throws away the packets why?




Class-map: debrecen (match-any)

      6100639 packets, 2386603748 bytes

      30 second offered rate 1179000 bps, drop rate 3000 bps

      Match: access-group name debrecen

        6100639 packets, 2386603748 bytes

        30 second rate 1179000 bps

      Queueing

      queue limit 64 packets

      (queue depth/total drops/no-buffer drops) 0/26308/0

      (pkts output/bytes output) 3024421/1270775183

      shape (average) cir 1900000, bc 7600, be 7600

      target shape rate 1900000


      Service-policy : WAN-OUTPUT-V.1


        queue stats for all priority classes:

          Queueing

          queue limit 64 packets

          (queue depth/total drops/no-buffer drops) 0/0/0

          (pkts output/bytes output) 661602/88789612


        Class-map: WAN_DSCP_EF (match-all)

          1323206 packets, 143171814 bytes

          30 second offered rate 2000 bps, drop rate 0 bps

          Match: ip dscp ef (46)

          Priority: 17% (323 kbps), burst bytes 8050, b/w exceed drops: 0


          QoS Set

            cos 5

              Packets marked 661602


        Class-map: WAN_DSCP_CS3 (match-any)

          16294 packets, 8056869 bytes

          30 second offered rate 0 bps, drop rate 0 bps

          Match: ip dscp cs3 (24)

            0 packets, 0 bytes

            30 second rate 0 bps

          Match: ip dscp af41 (34)

            0 packets, 0 bytes

            30 second rate 0 bps

          Queueing

          queue limit 64 packets

          (queue depth/total drops/no-buffer drops) 0/0/0

          (pkts output/bytes output) 8147/4249838

          bandwidth 3% (57 kbps)


        Class-map: WAN_DSCP_CS1 (match-any)

          1244538 packets, 279892316 bytes

          30 second offered rate 109000 bps, drop rate 3000 bps

          Match: ip dscp cs1 (8)

            0 packets, 0 bytes

            30 second rate 0 bps

          Match: protocol eigrp

            0 packets, 0 bytes

            30 second rate 0 bps

          Queueing

          queue limit 128 packets

          (queue depth/total drops/no-buffer drops) 0/26308/0

          (pkts output/bytes output) 596188/153156045

          bandwidth 40% (760 kbps)

------------------------------------------------

------------------------------------------------


GigabitEthernet0/3 is up, line protocol is up

  Hardware is MV64460 Internal MAC, address is 0019.56b2.c419 (bia 0019.56b2.c419)

  Description: INTERLINK Multiflex

  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,

     reliability 255/255, txload 2/255, rxload 1/255

  Encapsulation 802.1Q Virtual LAN, Vlan ID  1., loopback not set

  Keepalive set (10 sec)

  Full-duplex, 1000Mb/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 19:18:51

  Input queue: 0/300/669/0 (size/max/drops/flushes); Total output drops: 275049

  Queueing strategy: Class-based queueing

  Output queue: 102/1500/0 (size/max total/drops)

  30 second input rate 5518000 bits/sec, 3183 packets/sec

  30 second output rate 9701000 bits/sec, 3662 packets/sec

     120693102 packets input, 4292419309 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     1 input errors, 0 CRC, 0 frame, 0 overrun, 1 ignored

     0 watchdog, 19340047 multicast, 0 pause input

     0 input packets with dribble condition detected

     128241462 packets output, 4017681995 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

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Joseph W. Doherty Tue, 01/24/2012 - 07:10
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Posting


Might be insufficient queue space for bursts.

Joseph W. Doherty Wed, 01/25/2012 - 02:11
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Posting


KAROLY KOHEGYI wrote:


The no-buffer drops is zero!


How can i check the queue space?

If I remember correctly, no-buffer drops being zero just means you did not run out of physical buffer space.  The drops you're seeing, I believe, are you're just hitting your logical queue depths.  The queue limits are what might be increased.

Joseph W. Doherty Wed, 01/25/2012 - 07:06
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The     Author of this posting offers the information contained within this     posting without consideration and with the reader's understanding  that    there's no implied or expressed suitability or fitness for any   purpose.   Information provided is for informational purposes only and   should not   be construed as rendering professional advice of any kind.   Usage of  this  posting's information is solely at reader's own risk.


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In     no event shall Author be liable for any damages whatsoever   (including,   without limitation, damages for loss of use, data or   profit) arising  out  of the use or inability to use the posting's   information even if  Author  has been advised of the possibility of  such  damage.


Posting


KAROLY KOHEGYI wrote:


The queue-depth is zero also!


it is confuse!

Queue-depth is number of packets in queue at time of snapshot - not uncommon to get drops and not "catch" packets in queue in cases of transient bursts.

KAROLY KOHEGYI Wed, 01/25/2012 - 03:20
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Hi,

Here is the newest confuse issue!


The offered rate is higher than shap rate and no drops ! (close to  shape peak !!! )


sho policy-map interface output class pecs

GigabitEthernet0/1


GigabitEthernet0/3


  Service-policy output: MF


    Class-map: pecs (match-any)

      46762967 packets, 21107524803 bytes

      30 second offered rate 3665000 bps, drop rate 0 bps

      Match: access-group name pecs

        46762968 packets, 21107524681 bytes

        30 second rate 3665000 bps

      Queueing

      queue limit 64 packets

      (queue depth/total drops/no-buffer drops) 166/155121/0

      (pkts output/bytes output) 23505715/11060330966

      shape (average) cir 1900000, bc 7600, be 7600

      target shape rate 1900000


      Service-policy : WAN-OUTPUT-V.1


        queue stats for all priority classes:

          Queueing

          queue limit 64 packets

          (queue depth/total drops/no-buffer drops) 0/0/0

          (pkts output/bytes output) 3019213/402263119


        Class-map: WAN_DSCP_EF (match-all)

          6027535 packets, 646795939 bytes

          30 second offered rate 43000 bps, drop rate 0 bps

          Match: ip dscp ef (46)

          Priority: 17% (323 kbps), burst bytes 8050, b/w exceed drops: 0


          QoS Set

            cos 5

              Packets marked 3019213


        Class-map: WAN_DSCP_CS3 (match-any)

          81716 packets, 73702102 bytes

          30 second offered rate 4000 bps, drop rate 0 bps

          Match: ip dscp cs3 (24)

            0 packets, 0 bytes

            30 second rate 0 bps

          Match: ip dscp af41 (34)

            0 packets, 0 bytes

            30 second rate 0 bps

          Queueing

          queue limit 64 packets

          (queue depth/total drops/no-buffer drops) 0/83/0

          (pkts output/bytes output) 40779/37813432

          bandwidth 3% (57 kbps)


        Class-map: WAN_DSCP_CS1 (match-any)

          2480434 packets, 382699335 bytes

          30 second offered rate 2000 bps, drop rate 0 bps

          Match: ip dscp cs1 (8)

            0 packets, 0 bytes

            30 second rate 0 bps

          Match: protocol eigrp

            0 packets, 0 bytes

            30 second rate 0 bps

          Queueing

          queue limit 128 packets

          (queue depth/total drops/no-buffer drops) 0/33688/0

          (pkts output/bytes output) 1345706/227547725

          bandwidth 40% (760 kbps)


        Class-map: WAN_DSCP_CS2 (match-all)

          512708 packets, 73151425 bytes

          30 second offered rate 2000 bps, drop rate 0 bps

          Match: ip dscp cs2 (16)

          Queueing

          queue limit 128 packets

          (queue depth/total drops/no-buffer drops) 0/0/0

          (pkts output/bytes output) 256354/43483468

          bandwidth 15% (285 kbps)


        Class-map: WAN_DSCP_AF11 (match-all)

          20029430 packets, 2618963100 bytes

          30 second offered rate 166000 bps, drop rate 0 bps

          Match: ip dscp af11 (10)

          Queueing

          queue limit 64 packets

          (queue depth/total drops/no-buffer drops) 0/1929/0

          (pkts output/bytes output) 10117875/1580628559

          bandwidth 5% (95 kbps)


        Class-map: class-default (match-any)

          17631141 packets, 17312212798 bytes

          30 second offered rate 3448000 bps, drop rate 0 bps

          Match: any

          Queueing

          queue limit 256 packets

          (queue depth/total drops/no-buffer drops) 165/119421/0

          (pkts output/bytes output) 8725788/8768594663

          bandwidth 20% (380 kbps)

mmihalyf Tue, 01/24/2012 - 09:31
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Can you please try increasing the BC and BE values after your shape command?

Joseph W. Doherty Tue, 01/24/2012 - 10:05
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The    Author of this posting offers the information contained within this    posting without consideration and with the reader's understanding that    there's no implied or expressed suitability or fitness for any  purpose.   Information provided is for informational purposes only and  should not   be construed as rendering professional advice of any kind.  Usage of  this  posting's information is solely at reader's own risk.


Liability Disclaimer


In    no event shall Author be liable for any damages whatsoever  (including,   without limitation, damages for loss of use, data or  profit) arising  out  of the use or inability to use the posting's  information even if  Author  has been advised of the possibility of such  damage.


Posting


An interesting suggestion.  Newer IOS seem to default to a 4 ms Tc rather than 25 ms Tc.  What you thinking for Tc, maybe 10 ms (19,000 Bc)?

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