IETF RFC 7212 PDF

The MPLS Generic Associated Channel (G-ACh) provides an auxiliary logical data channel associated with a Label Switched Path (LSP), a pseudowire, or a section (link) over which a variety of protocols may flow. These protocols are commonly used to provide Operations, Administration, and Maintenance (OAM) mechanisms associated with the primary data channel. This document specifies simple procedures by which an endpoint of an LSP, pseudowire, or section may inform the other endpoints of its capabilities and configuration parameters, or other application-specific information. This information may then be used by the receiver to validate or adjust its local configuration, and by the network operator for diagnostic purposes.