This defines whether the control word will be sent with each packet by the local node. Enabling the control word adds a small header to every pseudowire packet carrying sequencing and payload-type information that helps the far end detect misordered or fragmented frames and correctly identify padding, which matters most for Ethernet or other Layer 2 payloads that could otherwise be misinterpreted as a valid MPLS label stack by intermediate devices doing ECMP hashing. For example, enabling the control word on a pseudowire carrying small Ethernet frames close to the minimum frame size helps the remote PE correctly distinguish real payload from padding, which raw frames without a control word can otherwise make ambiguous.