TECHNOLOGY

Pseudowire

OAM

OAM capabilities in Pseudowire circuits are provided through the implementation of virtual circuit connectivity verification (VCCV). VCCV defines extensions to Pseudowire signaling that enable a diagnostic channel for the Pseudowire circuit. In the HSX 6000, the diagnostic channel uses the bidirectional forwarding detection (BFD) protocol as the fault detection mechanism.

VCCV depends on the availability of the control word on the Pseudowire encapsulations for de multiplexing the control traffic from the data traffic. The HSX 6000 supports in-band control messages that are sent using the same label stack as the data traffic and are de-multiplexed from the data by using a field in the control word. The PWid FEC element and the PWid GenFEC element each include a C-bit value that indicates the intended use of the control word. This occurs during Pseudowire circuit establishment when the LDP peers negotiate the use of the control word. If both peers prefer the use of the control word, then a Pseudowire circuit is established with the control word enabled, otherwise the Pseudowire circuit is established with the control word disabled.