Install Guide

Table Of Contents
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.
Back-Off Mechanism
If the sampling rate for an interface is set to a very low value, the CPU can get overloaded with flow samples under high-traffic
conditions.
In such a scenario, a binary back-off mechanism gets triggered, which doubles the sampling-rate (halves the number of samples
per second) for all interfaces. The backoff mechanism continues to double the sampling-rate until the CPU condition is cleared.
This is as per sFlow version 5 draft. After the back-off changes the sample-rate, you must manually change the sampling rate to
the desired value.
As a result of back-off, the actual sampling-rate of an interface may differ from its configured sampling rate. You can view the
actual sampling-rate of the interface and the configured sample-rate by using the show sflow command.
sFlow on LAG ports
When a physical port becomes a member of a LAG, it inherits the sFlow configuration from the LAG port.
Enabling Extended sFlow
Extended sFlow packs additional information in the sFlow datagram depend on the type of sampled packet. The platform
supports extended-switch information processing only.
Extended sFlow packs additional information in the sFlow datagram depending on the type of sampled packet. You can enable
the following options:
extended-switch 802.1Q VLAN ID and 802.1p priority information.
extended-router Next-hop and source and destination mask length.
extended-gateway Source and destination AS number and the BGP next-hop.
NOTE:
The entire AS path is not included. BGP community-list and local preference information are not included. These
fields are assigned default values and are not interpreted by the collector.
Enable extended sFlow.
sflow [extended-switch] [extended-router] [extended-gateway] enable
By default packing of any of the extended information in the datagram is disabled.
Confirm that extended information packing is enabled.
show sflow
The bold line shows that extended sFlow settings are enabled on all three types.
If you did not enable any extended information, the show output displays the following (shown in bold).
DellEMC#show sflow
sFlow services are disabled
Global default sampling rate: 32768
Global default counter polling interval: 20
Global extended information enabled: none
0 collectors configured
0 UDP packets exported
0 UDP packets dropped
0 sFlow samples collected
0 sFlow samples dropped due to sub-sampling
sFlow
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