In virtual in-path deployments such as WCCP, traffic moves in and out of the same WAN interface. The LAN interface is not used. When the SteelHead exports data to a data flow collector, all traffic has the WAN interface index. Although it is technically correct for all traffic to have the WAN interface index because the input and output interfaces are the same, it is impossible to use the interface index to distinguish between LAN-to-WAN and WAN-to-LAN traffic.

You can configure the fake index feature on your SteelHead to insert the correct interface index before exporting data to a data flow collector.

For information about configuring the fake index feature, see Configuring Flow Data Exports in Virtual In-Path Deployments.