Displaying Sflow Information - Extreme Networks ExtremeWare XOS Guide Manual

Status Monitoring and Statistics
that the polling interval is 20 seconds and there are 40 counters to poll. Two ports will be polled each
second, until all 40 are polled. To configure the polling interval, use the following command:
configure sflow poll-interval <seconds>
Global Sampling Rate. This is the rate that newly enabled sFlow ports will have their sample rate set to.
Changing this rate will not affect currently enabled sFlow ports. The default sample rate is 8192, so by
default sFlow samples one packet out of every 8192 received. You configure the switch to use a different
sampling rate with the following command:
configure sflow sample-rate <number>
For example, if you set the sample rate number to 16384, the switch samples one out of every 16384
packets received. Higher numbers mean fewer samples and longer times between samples. If you set
the number too low, the number of samples can be very large, which increases the load on the switch.
Do not configure the sample rate to a number lower than the default unless you are sure that the traffic
rate on the source is low.
Per Port Sampling Rate. You can set the sampling rate on individual ports, using the following
command:
configure sflow ports <portlist> sample-rate <number>
For BlackDiamond 10K only—At the hardware level, all ports on the same slot are sampled at the
same rate, so if one port is configured to sample less frequently than another on the same slot, the extra
samples are discarded. This is indicated in the output of the command
show sflow {configuration}
as the sub-sampling factor. For example, if one port is configured to sample one packet per every 8192
packets, and the second port on the same slot is configured to sample one packet per every 16384
packets, the second port will show a sub-sampling factor of two.
Maximum CPU Sample Limit. A high number of samples can cause a heavy load on the switch CPU. To
limit the load, there is a CPU throttling mechanism to protect the switch. Whenever the limit is reached,
the sample rate value is doubled on the slot from which the maximum number of samples are received.
For ports on that slot that are sampled less frequently, the sampling rate is not changed; the sub-
sampling factor is adjusted downward. To configure the maximum CPU sample limit, use the following
command:
configure sflow max-cpu-sample-limit <rate>
Unconfiguring sFlow
You can reset the any configured values for sFlow to their default values and remove from sFlow any
configured collectors and ports by using the following command:
unconfigure sflow

Displaying sFlow Information

To display the current configuration of sFlow, use the following command:
show sflow {configuration}
To display the sFlow statistics, use the following command:
show sflow statistics
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ExtremeWare XOS 11.1 Concepts Guide