Configuring Sflow; Establishing The Configuration Task - Huawei S9300 Configuration Manual

S9300&S9300E Terabit Routing Switch
Configuration Guide - Network Management
sFlow Sampling Modes
An sFlow agent provides two sampling modes: flow sampling and counter sampling.
Flow sampling
Flow sampling is based on data packets. An sFlow agent copies packets in one direction or both
directions on an interface based on the sampling ratio, parses the packets, and encapsulates
packets and parsing result into sFlow packets. Then the sFlow agent sends the sFlow packets to
an sFlow collector.
The sFlow agent samples data packets on an interface in two ways: fixed sampling and random
sampling.
In fixed sampling mode, the sFlow agent starts a counter on an interface. The sampling ration
is 1/N and the initial value of the counter is N. The value of the counter decreases by 1 each time
the interface processes a packet. When the value of the counter is reduced to 0, the sFlow agent
resets the counter and repeats the preceding operations.
In random sampling mode, the sFlow agent allocates a random value to each packet processed
by an interface. The random value ranges from 0 to N. The threshold is set to a fixed value n
ranging from 0 to N. When the random value is smaller than the threshold, the sFlow agent
samples packets. The actual sampling ratio is n/(N+1).
The S9300&S9300E supports only random sampling.
In flow sampling, an sFlow agent can sample packets in one direction or in both directions on
an interface. To reduce the number of sent sFlow packets, set the maximum length of data starting
from the original packet header that can be copied from a sampled packet. You can set the
sampling ratio to limit the number of sampled packets.
Counter sampling
Counter sampling is based on traffic statistics on an interface. An sFlow agent periodically
obtains traffic statistics on an interface, encapsulates the traffic statistics into sFlow packets, and
sends them to an sFlow collector.
Comparison between the two sampling modes
Flow sampling and counter sampling are independent of each other. Flow sampling obtains
information about flows of a specified service, whereas counter sampling obtains traffic statistics
on an interface. It is recommended that you use both the two sampling modes.

11.3 Configuring sFlow

This section describes how to configure sFlow.

11.3.1 Establishing the Configuration Task

Before configuring sFlow, familiarize yourself with the applicable environment, complete the
pre-configuration tasks, and obtain the data required for the configuration. This will help you
complete the configuration task quickly and accurately.
Applicable Environment
Network maintenance personnel often use the traffic monitoring technique to monitor networks.
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