Cisco Nexus 5600 Series - Flow Record; Flow Exporter; Netflow Match Keys

All key values must match for the packet to count in a given flow. A flow might gather other fields of interest,
depending on the export record version that you configure. Flows are stored in the NetFlow cache.
The flow record determines the type of data to be collected for a flow. The flow monitor combines the flow
record and flow exporter with the NetFlow cache information.
Cisco NX-OS gathers NetFlow statistics in sampled mode. This means that packets on the interface or
subinterface are analyzed at the configured rate.
Flow Record
A flow record defines the keys that NetFlow uses to identify packets in the flow as well as other fields of
interest that NetFlow gathers for the flow. You can define a flow record with any combination of keys and
fields of interest. Cisco NX-OS supports a rich set of keys. A flow record also defines the types of counters
gathered per flow. You can configure 32-bit or 64-bit packet or byte counters. The key fields are specified
with the match keyword. The fields of interest and counters are specified under the match keyword.
Cisco NX-OS enables the following match fields as the defaults when you create a flow record:
•
match interface input
•
match interface output
•
match flow direction
Flow Exporter
A flow exporter contains network layer and transport layer details for the NetFlow export packet. You can
configure the following information in a flow exporter:
•
Export destination IPv4 or IPv6 address
•
Source interface
•
UDP port number (where the collector is listening for NetFlow packets)
•
Export format
NetFlow export packets use the IP address that is assigned to the source interface. If the source interface
does not have an IP address assigned to it, the flow exporter will be inactive.
Note
Cisco NX-OS exports data to the remote collector, using UDP frames, whenever a timeout occurs. By default,
the flow timeout value is set to 15 seconds.
NetFlow Match Keys
To identify a flow you can choose one or more match keys as part of the flow record.
NetFlow supports the following match keys to identify flows:
•
IPv4 source and IPv4 destination addresses
Cisco Nexus 5600 Series NX-OS System Management Configuration Guide, Release 7.x
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Configuring NetFlow
Flow Record