New module mod_vpp. Compile using make FEATURES=VPP. This module receives packet-samples and counter-samples generated by the vpp-sflow plugin https://github.com/sflow/vpp-sflow. The VPP plugin sends random packet-samples on the Linux Netlink PSAMPLE multicast channel, and periodic interface counters on a Netlink USERSOCK multicast channel. If there are interfaces on the server that were not turned over to VPP, then they can still be monitored as before.