Virtual circuit connectivity verification (VCCV) is an end-to-end fault detection and diagnostic mechanism for a PW. VCCV is, in its simplest description, a control channel between a PW's ingress and egress points over which connectivity verification messages can be sent.
VCCV can detect and diagnose the connectivity of the forwarding paths on a PW.
VCCV ping, an extension to LSP ping, is a tool used to manually test the connectivity of a VC. VCCV defines a series of messages exchanged between PEs for PW connectivity verification. To ensure that VCCV packets and PW data packets are transmitted along the same path, VCCV packets must be encapsulated in the same way and transmitted over the same tunnel as PW data packets.