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Configuring Specify Collectors
The sflow collector command allows identification of sFlow collectors to which sFlow datagrams are forwarded.
You can specify up to two sFlow collectors. If you specify two collectors, the samples are sent to both.
● Identify sFlow collectors to which sFlow datagrams are forwarded.
CONFIGURATION mode
sflow collector ip-address agent-addr ip-address [number [max-datagram-size number] ] |
[max-datagram-size number ]
The default UDP port is 6343.
The default max-datagram-size is 1400.
Changing the Polling Intervals
The sflow polling-interval command configures the polling interval for an interface in the maximum number of seconds
between successive samples of counters sent to the collector.
This command changes the global default counter polling (20 seconds) interval. You can configure an interface to use a
different polling interval.
To configure the polling intervals globally (in CONFIGURATION mode) or by interface (in INTERFACE mode), use the following
command.
● Change the global default counter polling interval.
CONFIGURATION mode or INTERFACE mode
sflow polling-interval interval value
○ interval value: in seconds.
The range is from 15 to 86400 seconds.
The default is 20 seconds.
Changing the Sampling Rate
The sflow sample-rate command, when issued in CONFIGURATION mode, changes the default sampling rate.
By default, the sampling rate of an interface is set to the same value as the current global default sampling rate. If the
value entered is not a correct power of 2, the command generates an error message with the previous and next power-of-2
value. Select one of these two numbers and re-enter the command. (For more information on values in power-of-2, refer to
Sub-Sampling.)
To change the sampling rate either globally or on an interface, use the following command.
● Change the global or interface sampling rate.
CONFIGURATION mode or INTERFACE mode
[no] sflow sample-rate sample-rate
sample-rate: The range is from 256 to 8388608 for the C-Series and S-Series. The range is from 2 to 8388608 for the
E-Series.
The rate must be entered in factors of 2 (for example, 4096 or 8192).
Sub-Sampling
The sFlow sample rate is not the frequency of sampling, but the number of packets that are skipped before the next sample is
taken.
Therefore, the sFlow agent uses sub-sampling to create multiple sampling rates per port-pipe. To achieve different sampling
rates for different ports in a port-pipe, the sFlow agent takes the lowest numerical value of the sampling rate of all the ports
within the port-pipe and configures all the ports to this value. The sFlow agent is then able to skip samples on ports where you
require a larger sampling rate value.
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