12-31-2008 12:48 AM - edited 03-04-2019 03:17 AM
Hello,
I read the CBWFQ document regarding of average queue size.
http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/fswfq26.html#wp1019686
The average queue size is based on the previous average and the current size of the queue. The formula
is as follows, where n is the exponential weight factor, a user-configurable value:
average = (old_average * (1-1/2^n)) + (current_queue_size * 1/2^n)
My question is that, how can I know the current queue size in advance? Is there any command can show it? Do you have any idear.
Any experience or insight info is appreciated.
jeffrey
Solved! Go to Solution.
01-01-2009 03:48 PM
.
.
Class-map: dscp_AF2x (match-any)
18930447 packets, 12209444772 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: ip dscp cs2 (16) af21 (18) af22 (20) af23 (22)
18930442 packets, 12209444772 bytes
30 second rate 0 bps
Queueing
Output Queue: Conversation 139
Bandwidth remaining 16 (%)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
exponential weight: 9
mean queue depth: 0
.
.
I've highlighted the average WRED queue depth stat.
By the way, do you have any idear and experience about to set Minimum and Maximum threshold value regarding to ethernet bandwidth?
You might begin with 1/2 of (max as BDP and min 1/3 max). This also assumes TCP traffic.
12-31-2008 04:33 AM
Hello Jeffrey,
you can see the current size with sh queueing
sh queueing int ser2/0/0
Interface Serial2/0/0 queueing strategy: VIP-based fair queueing
Serial2/0/0 queue size 0
pkts output 26856883303, wfq drops 0, nobuffer drops 0
WFQ: aggregate queue limit 6614 max available buffers 6614
Class 1: bandwidth 3000 exceed drops 0
Class 2: bandwidth 30000 exceed drops 0
The average queue size is used by WRED to manage congestion.
Hope to help
Giuseppe
12-31-2008 04:47 AM
"Is there any command can show it?"
Besides using sh queuing interface, as noted in Giuseppe's post, when using CBWFQ, sh policy-map out interface should usually show WRED's current average queue size in the stats.
"My question is that, how can I know the current queue size in advance?"
Not practically.
01-01-2009 06:37 AM
Hi Joseph and all,
I am use CBWFQ. Here is sho policy-map interface out, it seem can not see current average queue size.
I know the current average should change frequently per second. If exceed minimum threshold value, should some random drop occur. I want to know the current average queue size, and can help me to resize the threshold. By the way, do you have any idear and experience about to set Minimum and Maximum threshold value regarding to ethernet bandwidth?
PE2-C2651XM#show policy-map interface fastEthernet 0/1 output FastEthernet0/1
Service-policy output: DSCP_OUT
Class-map: class-default (match-any)
18957722 packets, 12212120505 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: any
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
50000000/50000000 312500 1250000 1250000 25 156250
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 18957715 3622180843 0 0 no
Service-policy : DSCP_OUT_1
Class-map: dscp_AF2x (match-any)
18930447 packets, 12209444772 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: ip dscp cs2 (16) af21 (18) af22 (20) af23 (22)
18930442 packets, 12209444772 bytes
30 second rate 0 bps
Queueing
Output Queue: Conversation 139
Bandwidth remaining 16 (%)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
exponential weight: 9
mean queue depth: 0
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 52 500 1/1
af22 18930444/12209440716 0/0 0/0 52 250 1/1
af23 0/0 0/0 0/0 52 250 1/1
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 0/0 0/0 0/0 20 40 1/10
Best regard
Thanks
Jeffrey
01-01-2009 03:48 PM
.
.
Class-map: dscp_AF2x (match-any)
18930447 packets, 12209444772 bytes
30 second offered rate 0 bps, drop rate 0 bps
Match: ip dscp cs2 (16) af21 (18) af22 (20) af23 (22)
18930442 packets, 12209444772 bytes
30 second rate 0 bps
Queueing
Output Queue: Conversation 139
Bandwidth remaining 16 (%)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
exponential weight: 9
mean queue depth: 0
.
.
I've highlighted the average WRED queue depth stat.
By the way, do you have any idear and experience about to set Minimum and Maximum threshold value regarding to ethernet bandwidth?
You might begin with 1/2 of (max as BDP and min 1/3 max). This also assumes TCP traffic.
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