BGP Link-State (BGP-LS) enables distribution of topology info from the network to a controller or an application in standard so it can find out the network topology. This doc defines a Subcode for the BGP Cease NOTIFICATION message for when a BGP connection is staying shut owing to a BFD session likely down. This document defines two new flags in the IOAM Trace Option headers, especially the Loopback and Active flags.