Specifications

Configuring NetFlow on the X-Series Router
May 18, 2011 Page 11 of 21
Default NetFlow Settings for S-Series, N-Series, and K-Series Systems
Table 1providesalistingofthedefaultNetFlowconfigurationsettingsforS‐Series,N‐Series,and
K‐Seriessystems.
Configuring NetFlow on the X-Series Router
OntheX‐Seriesrouter,NetFlowclassificationandcachingareperformedontheInput/Output
Modules(IOMs),whileNetFlowexportfunctionalityisperformedontheControlModule(CM).
Packetsaresampledatingressattherateconfiguredforthewholesystemwiththeset
sampling‐ratecommand(seeProcedure 2onpage 12).The
IOMsclassifythesampledpackets
intoflows,updateNetFlowcounters,anddeterminetheendoftheflows.TheIOMssendflow
datatotheCMforexportwhentheconfiguredexport‐intervaltimeexpires(defaultis30minutes)
orwhenthecacheisfull.
TheNetFlowexportprocessonthe
CMgathersanyfurtherdataneededtocompletethedata
recordformatfortheconfiguredNetFlowversionandsendstheflowrecordstotheconfigured
NetFlowcollector.NotethatonlyoneNetFlowexportdestination(collector)canbeconfigured
perX‐Seriessystem.
NetFlowcanbeenabledonanyportonthe
X‐Seriesrouter.
Table 1 Default NetFlow Configuration Settings for S-Series and N-Series Systems
Parameter Description Default Value
Cache Status Whether NetFlow caching is globally enabled or
disabled.
Disabled globally
Destination IP address The IP address of the NetFlow collector which is the
destination of the NetFlow UDP packets.
None
Export Interval The time out interval when the NetFlow cache is
flushed and the data is exported, if the maximum
number of entries has not been reached.
30 minutes
Export Version The NetFlow flow record format used when
exporting NetFlow packets. Version can be either 5
or 9.
Version 5
Inactive flow timer The number of seconds after a flow stops before
NetFlow sends an export packet for that flow to the
collector.
40 seconds
(non-configurable)
Optional Export Data The exporting of MAC and VLAN data by source and
destination address.
Disabled
Port state Whether NetFlow is enabled or disabled on a port. Disabled
Refresh-rate The number of export packets sent before NetFlow
retransmits a template to the collector when using
NetFlow Version 9.
20 export packets
Timeout-period When using NetFlow Version 9, the number of
minutes NetFlow waits before retransmitting a
template to the collector.
30 minutes