Hello,
This is hidden command and it is NOT supported.
General purpose of this command is
This knob makes VCCV BFD sessions at ppmd level to run on Routing Engine CPU instead of linecard CPUs, for debugging purposes.
VCCV is Virtual Circuit Connectivity Verification = periodic pseudowire keepalives http://www.ietf.org/rfc/rfc5085.txt
BFD is Bidirectional Forwarding Detection protocol == periodic UDP keepalive protocol http://en.wikipedia.org/wiki/Bidirectional_Forwarding_Detection
HTH
Thanks
Alex