sFlow: Transit IP-in-IP support 

You can use sFlow technology to sample IP over IP (IP-IP) traffic at a physical port. This feature is supported for IP-IP tunnels with an IPv4 outer header that carry IPv4 or IPv6 traffic. You can use sFlow monitoring technology to randomly sample network packets from IP-IP tunnels to send the samples to a destination collector for monitoring. Devices that act as an IP-IP tunnel entry point, transit device, or tunnel endpoint support sFlow sampling.