IPFIX is an IETF protocol for exporting flow information.
A flow is defined as a set of packets transmitted in a specific timeslot, and sharing the same 5-tuple values - source IP address, source port, destination IP address, destination port, and protocol. The flow information may include properties such as timestamps, packets/bytes count, Input/Output interfaces, TCP Flags, VXLAN ID, Encapsulated flow information, and so on.
A VDS in vSphere environment can be configured to export flow information using IPFIX. Flow monitoring has to be enabled on all the port groups attached to the VDS. If packets arrive on port X of a VDS and exit from port Y, a corresponding flow record is emitted if flow monitoring is enabled on port Y.
To analyze the complete information of any session, IPFIX data about packets in both the directions is required. Refer following diagram where VM-A is connected to DVPG-A and is talking to VM-C. Here DVPG-A will only provide data about the C→A packets, and DVPG-Uplink will provide data about A→C packets. To get the complete information of A's traffic, IPFIX should be enabled on DVPG-A, DVPG-uplink.
vRealize Network Insight Proxy VM has built-in collector/receiver for IPFIX flow information. You can enable the IPFIX information collection in the vCenter Data Source settings at various levels of granularity. To enable IPFIX information at vCenter level select the Enable NetFlow (IPFIX) on this vCenter check box when you are adding the vCenter.
After you select the check box, a list of available VDS in the vCenter is displayed. Select the VDS for which you want to enable IPFIX.
A notification icon is displayed for the VDS where one of the hosts has unsupported version of ESXi. If vRealize Network Insight has detected that IPFIX is already configured for a VDS with some other IP address apart from vRealize Network Insight Proxy VM then it displays an Override button. You can click Override to view the list of DVPGs under that VDS.
The list of available DVPGs for the selected VDS is displayed. By default all the DVPGs are selected. Turn Manual Selection on to select specific DVPGs for which you want to enable IPFIX. Select the desired DVPGs and click Submit.
The DVPG with a notification icon denotes that it is the uplink DVPG and it cannot be deselected.