I am new for vpp，when i practicing this  exercise "https://wiki.fd.io/view/VPP/Progressive_VPP_Tutorial#Action:_Create_veth_interfaces_on_host" , i found ping from host to vpp is ok, while ping from vpp to host is not.  the topology is like "https://wiki.fd.io/view/File:Create_Interface_Topology.jpg" . After check the source code,i found the function run_ping_ip46_address called by ping_ip_address is like this .

as you see the parameter ping_burst and data_len should be exchaged.

BTW:vpp version is 17.04