WFQ Counters in Class-Default vs. Interface

From: Pierre-Alex GUANEL (paguanel@hotmail.com)
Date: Sun Sep 16 2007 - 09:16:34 ART


Hello,

I was trying to see how WFQ behaves when using extremely low
parameters for CDT and hold queue. Several questions in regards
to the counters of WFQ in the class-default vs WFQ on the interface
came out in the process.

Please have a look and thank you in advance for any response
you send.

===========
Diagram
===========
FTP_client----R2 ser0/1---128K--ser-0/3---R3-----FTP_Server

=======
Config
========

! r3

interface Serial0/3
...
 load-interval 30
 clock rate 128000
 fair-queue 1 16 0
 service-policy output WRED_pol
 hold-queue 1 out
end

class-map match-all FTP_tr
  match access-group name FTP_acl
!
!
policy-map chil_pol
  class class-default
   fair-queue 4096
   random-detect dscp-based
   random-detect dscp 0 1 10 10
!
policy-map WRED_pol
  class FTP_tr
   shape average 56000
   service-policy chil_pol

ip access-list extended FTP_acl
 permit tcp any eq ftp any
 permit tcp any eq ftp-data any

!

=============
Questions
==============

1- what is the relationship between the number of conversation queues in the
fair-queue of the default class "child_pol" (4096) and the number of
converstation queues on the interface (16)

2- If I set both different, which one takes precedence / how can I verify
this?

3- In the fair-queue of the default class "child_pol", why can I only set the
"number of conversation" ? Are the other parameters inherited from the main
interface? Why?

4- Why does the "Total output drops" increment, but not the "drops" of the
output queue? - See below "show inter ser 0/3 on Rack1R3"
I assume the "Total output drops" takes into account the WRED drop, where as
"drops" takes into account ???

5- Why does the "active" Conversation always say "0" and the output queue size
always say "0" when I actually have traffic going on? It seems that the "max
total" output queue and "max active" converstation queue actually correspond
to the "size" and "active" respectively... See below "show inter ser 0/3 on
Rack1R3"

Rack1R3#sh int ser 0/3
Serial0/3 is up, line protocol is up
  Hardware is PowerQUICC Serial
  Internet address is 1.1.1.3/29
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 10/255, rxload 3/255
  Encapsulation HDLC, loopback not set
  Keepalive set (10 sec)
  Last input 00:00:01, 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: 916
  Queueing strategy: weighted fair
  Output queue: 0/1/1/0 (size/max total/threshold/drops)
     Conversations 0/2/16 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 1158 kilobits/sec
  30 second input rate 21000 bits/sec, 35 packets/sec
  30 second output rate 63000 bits/sec, 36 packets/sec
     382648 packets input, 28420381 bytes, 0 no buffer
     Received 1452 broadcasts, 0 runts, 0 giants, 0 throttles
     5 input errors, 0 CRC, 4 frame, 0 overrun, 0 ignored, 0 abort
     400547 packets output, 75923709 bytes, 0 underruns
     0 output errors, 0 collisions, 9 interface resets
     0 output buffer failures, 0 output buffers swapped out
     6 carrier transitions
     DCD=up DSR=up DTR=up RTS=up CTS=up

Rack1R3#sh policy-map inter ser 0/3
 Serial0/3

  Service-policy output: WRED_pol

    Class-map: FTP_tr (match-all)
      22636 packets, 25871738 bytes
      30 second offered rate 50000 bps, drop rate 2000 bps
      Match: access-group name FTP_acl
      Traffic Shaping
           Target/Average Byte Sustain Excess Interval Increment
             Rate Limit bits/int bits/int (ms) (bytes)
            56000/56000 1988 7952 7952 142 994

        Adapt Queue Packets Bytes Packets Bytes Shaping
        Active Depth Delayed Delayed Active
        - 3 21675 24845550 20916 23833922 yes

      Service-policy : chil_pol

        Class-map: class-default (match-any)
          22636 packets, 25871738 bytes
          30 second offered rate 50000 bps, drop rate 2000 bps
          Match: any
          Queueing
            Flow Based Fair Queueing
            Maximum Number of Hashed Queues 4096
        (total queued/total drops/no-buffer drops) 4/110/0
             exponential weight: 9

   dscp Transmitted Random drop Tail drop Minimum Maximum
Mark
           pkts/bytes pkts/bytes pkts/bytes thresh thresh
prob
   af11 0/0 0/0 0/0 32 40
1/10
   af12 0/0 0/0 0/0 28 40
1/10
   af13 0/0 0/0 0/0 24 40
1/10
   af21 0/0 0/0 0/0 32 40
1/10
   af22 0/0 0/0 0/0 28 40
1/10
   af23 0/0 0/0 0/0 24 40
1/10
   af31 0/0 0/0 0/0 32 40
1/10
   af32 0/0 0/0 0/0 28 40
1/10
   af33 0/0 0/0 0/0 24 40
1/10
   af41 0/0 0/0 0/0 32 40
1/10
   af42 0/0 0/0 0/0 28 40
1/10
   af43 0/0 0/0 0/0 24 40
1/10
    cs1 0/0 0/0 0/0 22 40
1/10
    cs2 0/0 0/0 0/0 24 40
1/10
    cs3 0/0 0/0 0/0 26 40
1/10
    cs4 0/0 0/0 0/0 28 40
1/10
    cs5 0/0 0/0 0/0 30 40
1/10
    cs6 0/0 0/0 0/0 32 40
1/10
    cs7 0/0 0/0 0/0 34 40
1/10
     ef 0/0 0/0 0/0 36 40
1/10
   rsvp 0/0 0/0 0/0 36 40
1/10
default 2307/2669720 110/121556 0/0 1 10
1/10



This archive was generated by hypermail 2.1.4 : Sat Oct 06 2007 - 12:01:12 ART