Pseudowire control word for NGE traffic

The control word is a configurable option for PWs and is included in PW packets when it is configured. When control-word is enabled and NGE is used, the datapath creates two copies of the CW. One CW is both encrypted and authenticated, and is inserted after the ESP header. The other CW is not encrypted (clear form) and is inserted before the ESP header.

For cases where PW switching is configured, the NGE node ensures—in the CLI and with SNMP—that both segments of the PW have consistent configuration of the control word when encryption is being used.