To configure extended discovery to support the MPLS LDP session between the headend and tailend routers, the engineer must configure a targeted neighbor session. This action allows for the establishment of LDP sessions between routers that are not directly connected, which is necessary for setting up MPLS tunnels that span multiple hops in the network.

https://www.cisco.com/c/en/us/support/docs/storage-networking/management/200933-YANG- NETCONF-Configuration-Validation.html

Packet loops can occur during the configuration of BIDIR-PIM if not all parts of your network support this protocol or are configured correctly for it. If some routers or switches in your network don't understand or aren't configured for BIDIR-PIM, they can inadvertently forward packets back into parts of the network they were already in, creating a loop. Reference: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) - Multicast section.