failing to meet the required Sampling Interval. Once a second, the sFlow Agent examines the list of
counter sources and sends any counters that need to be sent to meet the sampling interval
requirement.
To access the sFlow Poller Configuration page, click
System
>
Advanced Configuration
>
sFlow
>
Poller
in the navigation menu.
Use the buttons to perform the following tasks:
•
To add an sFlow poller instance, click
Add
and complete the required information.
•
To edit an existing sFlow poller instance, select the appropriate checkbox or click the row to select
the sFlow poller instance and click
Edit
. Modify the sFlow poller configuration information as
needed.
•
To delete an sFlow poller instance, select one or more table entries and click
Remove
.
Table 75: sFlow Poller Configuration Fields
Field
Description
Poller
DataSource
The sFlow Sampler Datasource for this flow sampler. This Agent will support physical ports only.
Receiver Index
The sFlowReceiver for this sFlow Counter Poller. If set to zero, the poller configuration is set to
the default and the poller is deleted. Only active receivers can be set. If a receiver expires, then
all pollers associated with the receiver will also expire. The allowed range is 1 to 8.
Poller Interval
The maximum number of seconds between successive samples of the counters associated with
this data source.
Click
Refresh
to refresh the page with the most current data from the switch.
sFlow Sampler Configuration
The sFlow Agent collects a statistical packet-based sampling of the switched flows and sends them to
the configured receivers. A data source configured to collect flow samples is called a sampler.
Packet Flow Sampling
The Packet Flow Sampling mechanism carried out by each sFlow instance ensures that any packet
observed at a Data Source has an equal chance of being sampled, irrespective of the Packet Flow(s) to
which it belongs.
Packet Flow Sampling is accomplished as follows:
•
When a packet arrives on an interface, the Network Device makes a filtering decision to determine
whether the packet should be dropped.
•
If the packet is not filtered (dropped), a destination interface is assigned by the switching/routing
function.
•
At this point, a decision is made on whether or not to sample the packet. The mechanism involves a
counter that is decremented with each packet. When the counter reaches zero, a sample is taken.
When a sample is taken, the counter that indicates how many packets to skip before taking the next
sample is reset. The value of the counter is set to a random integer where the sequence of random
integers used over time is the Sampling Rate.
Configuring System Information
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