http://www.rfc-editor.org/rfc/rfc7347.txt
RFC 7347: Pre-standard Linear Protection Switching in MPLS Transport Profile (MPLS-TP), H. van Helvoort, J. Ryoo, H. Zhang, F. Huang, H. Li, A. D'Alessandro2014-09-01T23:00:00-00:00The specified mechanism supports 1+1 unidirectional/bidirectional protection switching and 1:1 bidirectional protection switching. It is purely supported by the MPLS-TP data plane and can work without any control plane.