Cisco Cisco IOS Software Release 12.2(33)SRE

Your router must be running Cisco IOS release 12.2(33)SRB or later to configure the Netflow v9 for IPv6 
feature.

Before you configure the Netflow v9 for IPv6 feature, you should understand the following concepts:

The NetFlow cache on the PFC captures statistics for flows routed in hardware. 

The PFC uses one of these flow masks to create NetFlow entries:

source-only—The cache contains one entry for each source IP address. All flows from a given 
source IP address use this entry. 

destination—The cache contains one entry for each destination IP address. All flows to a given 
destination IP address use this entry. 

destination-source—The cache contains one entry for each source and destination IP address pair. 
All flows between the same source and destination IP addresses use this entry. 

destination-source-interface—Adds the source VLAN SNMP ifIndex to the information in the 
destination-source flow mask. 

full—A separate cache entry is created for each IP flow. A full entry includes the source IP address, 
destination IP address, protocol, and protocol interfaces. 

full-interface—Adds the source VLAN SNMP ifIndex to the information in the full flow mask. 

See the 

 chapter of the Cisco 7600 Series Cisco IOS Software 

Configuration Guide, Release 12.2SR, for detailed information on NetFlow flow masks and flow 
records.

For all NetFlow export versions, the NetFlow export datagram consists of a header and a sequence of 
flow records. The header contains information such as sequence number, record count, and system 
uptime. The flow record contains flow information, such as IP addresses, ports, and routing information. 

NetFlow version 9 export format is the newest NetFlow export format. The distinguishing feature of the 
NetFlow version 9 export format is that it is template based. Templates make the record format 
extensible. NetFlow version 9 export format allows future enhancements to NetFlow without requiring 
concurrent changes to the basic flow-record format. 

The NetFlow version 9 export record format is different from the traditional NetFlow fixed format export 
record. In NetFlow version 9, a template describes the NetFlow data, and the flow set contains the actual 
data. This arrangement allows for flexible export. 

The use of templates with the NetFlow version 9 export format provides several other key benefits: