How to show the available bandwidth on a Multilink

Unanswered Question
Jan 25th, 2010

I am working at a client site whom has 2 T1's bundled together into a multilink on their 3845 ISR.


The Multilink is part of an MPLS circuit and uses Classes of Service to prioritize traffic and assign bandwidth to classes.


I was reading some old documentation that was explaining the difference between  the "bandwidth percent" command and the "bandwidth available percent" command.  The article was referencing a command called "show queueing interface XXXX"  and the output looked like:


R1#sh queueing int f1/0
Interface FastEthernet1/0 queueing strategy: fair
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: Class-based queueing
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 1/1 (allocated/max allocated)
     Available Bandwidth 80000 kilobits/sec


I wanted to perform this action on the client 3845 (to look at what the interface indicates is Available bandwidth) but i get the following output when I do:


GAMPLSRTR01#sho queueing inter mu1
show queueing command is depracated. Please useshow policy-map interface


The problem I have is that I do not see "Available bandwidth" when I perform a "show policy-map interface" command.


I am wondering if it wont show this to me because it is no longer included in the command output, or because i am working on a multilink.


Thanks

Kevin


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Giuseppe Larosa Mon, 01/25/2010 - 13:29

Hello Kevin,

if you have applied a service-policy you should use:


sh policy-map interface multilink1


Hope to help

Giuseppe

Kevin Melton Mon, 01/25/2010 - 14:48

Guiseppe


Can you please highlight in the following output where is shown the Available Bandwidth?  thx


GAMPLSRTR01#sho policy-map int mu1
Multilink1

  Service-policy output: QOS

    Class-map: COS2_TRAFFIC (match-all)
      60001043 packets, 52874998664 bytes
      30 second offered rate 1122000 bps, drop rate 0 bps
      Match: access-group 182
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 9/2/0
      (pkts output/bytes output) 211849/173538367
      QoS Set
        dscp af31
          Packets marked 60001043
      bandwidth remaining 40% (1200 kbps)
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 10 packets
        dscp     Transmitted       Random drop      Tail drop          Minimum                                                                                     Maximum     Mark
                  pkts/bytes     pkts/bytes       pkts/bytes          thresh                                                                                      thresh     prob

        af31      209984/171914729       2/1366           0/0                512          1024  1/10

    Class-map: COS3_TRAFFIC (match-all)
      18030917 packets, 11606984787 bytes
      30 second offered rate 140000 bps, drop rate 0 bps
      Match: access-group 183
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 34294/9068529
      QoS Set
        dscp af21
          Packets marked 18030917
      bandwidth remaining 25% (750 kbps)
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 2 packets
        dscp     Transmitted       Random drop      Tail drop          Minimum        Maximum     Mark
                  pkts/bytes     pkts/bytes       pkts/bytes          thresh         thresh     prob

        af21       33914/8976501         0/0              0/0                512          1024  1/10

    Class-map: class-default (match-any)
      68947587 packets, 32035395703 bytes
      30 second offered rate 1494000 bps, drop rate 0 bps
      Match: any
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops/flowdrops) 4/667741/0/0
      (pkts output/bytes output) 68291808/31750899322
      Fair-queue: per-flow queue limit 16
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 5 packets
        class     Transmitted       Random drop      Tail/Flow drop Minimum Maximum Mark
                  pkts/bytes    pkts/bytes       pkts/bytes    thresh  thresh  prob

        0        68276388/31742364351 643673/283910577  24013/6375385           20            40  1/10
        1               0/0               0/0              0/0                 22            40  1/10
        2             425/93913           0/0              0/0                 24            40  1/10
        3           11432/10515137       70/61581          0/0                 26            40  1/10
        4               0/0               0/0              0/0                 28            40  1/10
        5               0/0               0/0              0/0                 30            40  1/10
        6            9759/505695          4/225            9/435               32            40  1/10
        7               0/0               0/0              0/0                 34            40  1/10
GAMPLSRTR01#

Giuseppe Larosa Tue, 01/26/2010 - 02:35

Hello Kevin,

you are right there is not a direct indication of available BW


However, the policy-map provides you useful traffic counters if you sum the offered rate of all traffic classes you can know how much traffic is going on the multilink bundle, available BW is then:


Multilink1 BW - (sum of offered traffic on each class including default class)


sh ppp multilink can tell you many links are up:


sh ppp multilink


Multilink1, bundle name is
  Endpoint discriminator is XXXX
  Bundle up for 14w3d, total bandwidth 4096, load 1/255
  Receive buffer limit 24000 bytes, frag timeout 1000 ms
    0/0 fragments/bytes in reassembly list
    1901 lost fragments, 109671227 reordered
    1423/1022815 discarded fragments/bytes, 0 lost received
    0x551807 received sequence, 0x55A3C sent sequence
  Member links: 2 active, 0 inactive (max not set, min not set)
    Se0/1/0, since 14w3d
    Se0/1/1, since 8w0d


an eestimate can be given simply by sh interface multi1, again it gives you the tx/rx traffic


Hope to help

Giuseppe

Kevin Melton Tue, 01/26/2010 - 06:54

Guiseppe


Under class default there are exactly 7 rows of values (counters).  Do you know what each of these rows represents?


Thanks

Kevin

Giuseppe Larosa Tue, 01/26/2010 - 07:08

Hello Kevin,

under class-default is active WRED and those lines are the WRED statistics one row for IP Precedence


WRED handles congestion trying to avoid indifferentiated drop from the queue.


The idea is to drop before the queue is full and in a differentiated way depending on IP precedence or DSCP byte value


see


http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/config_wred_ps6350_TSD_Products_Configuration_Guide_Chapter.html



Hope to help

Giuseppe

Kevin Melton Tue, 01/26/2010 - 08:42

Giuseppe


Here is another question


Class-map: class-default (match-any)
      451274 packets, 170630003 bytes
      30 second offered rate 1265000 bps, drop rate 6000 bps
      Match: any
      Queueing
      queue limit 512 packets
      (queue depth/total drops/no-buffer drops) 0/593/0
      (pkts output/bytes output) 450682/170307760
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 2 packets

What does the 30 second offered rate mean in the above output (this is also from the show policy-map int XX command)?


thx

Kevin

Giuseppe Larosa Tue, 01/26/2010 - 09:43

Hello Kevin,

I would simply read offered rate as measured rate for this traffic class.

To be noted you can see also a drop rate so the actual tx rate should be offered rate - drop rate

if  you see the term offered rate is present for all classes in the output of sh policy-map interface


Hope to help

Giuseppe

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