05-14-2009 12:03 PM
Hello,
I'm having trouble with the configs mean on a qos queue, here is a snapshot of our 6500 switch.
mls qos
mls qos map cos-dscp 0 10 18 24 34 46 48 56
mls qos srr-queue input bandwidth 90 10
mls qos srr-queue input threshold 1 70 100
mls qos srr-queue input threshold 2 70 100
mls qos srr-queue input dscp-map queue 1 threshold 1 46
mls qos srr-queue input dscp-map queue 2 threshold 2 48 56
mls qos srr-queue output dscp-map queue 1 threshold 2 46
mls qos srr-queue output dscp-map queue 2 threshold 1 24
mls qos srr-queue output dscp-map queue 2 threshold 2 56
mls qos srr-queue output dscp-map queue 2 threshold 3 48
mls qos srr-queue output dscp-map queue 3 threshold 1 34 36 38
mls qos srr-queue output dscp-map queue 3 threshold 2 26 28 30
mls qos srr-queue output dscp-map queue 3 threshold 3 32
mls qos srr-queue output dscp-map queue 4 threshold 1 8 9 11 13 15 16 17 19
mls qos srr-queue output dscp-map queue 4 threshold 1 20 21 22 23 25 27 29 31
mls qos srr-queue output dscp-map queue 4 threshold 1 40 41 42 43 44 45 47
mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
mls qos srr-queue output dscp-map queue 4 threshold 3 0
mls qos queue-set output 1 threshold 1 75 200 100 400
mls qos queue-set output 1 threshold 2 75 150 100 400
mls qos queue-set output 1 threshold 3 75 150 50 400
mls qos queue-set output 1 threshold 4 50 150 50 400
mls qos queue-set output 1 buffers 15 20 25 40
Now if I'm reading this correctly the top line means we are using the CoS to determine the DSCP values. And the preceding lines are showing what threshold values the traffic is being assigned to. However what i'm not understanding is the output threshold values (the last 5 lines in the snapshot). What exactly are these values telling me? I know this is a pretty basic question but i'm still trying to wrap my head around QoS. Thanks
05-20-2009 07:23 AM
These values are queue-id drop-threshold1 drop-threshold2 reserved-threshold maximum-threshold.
You guarantee availability of the buffers, set drop thresholds, and configuring the maximum memory allocation of the queue-set by using the following global configuration command.
mls qos queue-set output (qset-id) threshold (queue-id drop-threshold1 drop-threshold2 reserved-threshold maximum-threshold).
Each threshold value is a percentage of the queue's allocated memory.
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