Configuring the NetFlow Export Version

The Extreme Networks S- and K-Series support NetFlow export versions 5 and 9. The default export version is 5.

The primary difference between the two versions is that version 5 is a fixed data record without multicast support, where version 9 is a flexible, extensible, template-based data record that provides the complete ifIndex value and 64-bit counters.

With NetFlow version 5, packets are made up of a series of data records and are exported to the collection server when the maximum number of NetFlow records is reached.

When transmitting NetFlow Version 5 reports, the S- and K-Series module use “NetFlow interface” indexes. Normally these would be actual MIB-2 ifIndex values, but the Version 5 record format limits the values to 2 bytes, which is not sufficient to hold 4-byte ifIndexes. NetFlow collector applications that use the in/out interface indexes to gather SNMP data about the interface (such as ifName) must translate the interface indexes using the Extreme Networks MIB etsysNetFlowMIB (1.3.1.6.1.4.1.5624.1.2.61).

With NetFlow version 9, packets are made up of templates containing a set of data records. Templates are sent after the period configured for the template timeout when a module or collection server first boots up. Data records for version 9 cannot be processed without an up-to-date template. Collectors ignore incoming packets until a template arrives. Templates are refreshed periodically based upon a packet refresh rate and timeout period. Setting the appropriate refresh rate for your S- or K-Series device must be determined, since the default settings of a 20-packet refresh rate and a 30-minute timeout may not be optimal for your environment. See Configuring NetFlow Export Version Refresh.

NetFlow Version 9 records generated by S- and K-Series modules use true MIB-2 ifIndex values since the template mechanism permits transmission of 4-byte ifIndexes. Version 9 also uses 8-byte packet and byte counters, so they are less likely to roll over. Check with your collector provider to determine if they provide the necessary support.

The current Extreme Networks Version 9 implementation:

• Does not support aggregation caches.
• Provides 15 IPv4 and 15 IPv6 predefined templates. The S- and K-Series firmware automatically selects the appropriate template for each flow depending on whether the flow is routed or switched, whether it is a TCP/UDP packet or not, and contains fields appropriate to the data records supported in the template. See NetFlow Version 9 Template Header Support for a listing of the header fields supported by the NetFlow Version 9 templates. See NetFlow Version 9 Template Data Record Field Support for a listing of the base data record fields supported by all NetFlow Version 9 templates. See NetFlow Version 9 Additional Template Specific Data Record Field Support for a listing of the additional template specific data record fields supported by the NetFlow Version 9 templates. See NetFlow Version 9 Templates for a listing of IPv4 and IPv6 Version 9 NetFlow templates by template ID and description.

Use the set netflow export-version {5|9} command to set the NetFlow export version.

Use the clear netflow export-version command to reset the export version to the default value of Version 5.