Nokia Verizon Nokia Cisco System Cisco System Juniper Networks Consider large networks deploying traditional PIM multicast service. Typically, each portion of these large networks have their own mandates and requirements. It might be desirable to deploy BIER technology in some part of these networks to replace traditional PIM services. In such cases downstream PIM states need to be signaled over the BIER Domain toward the source. This document specifies the procedures to signal PIM Join and Prune messages through a BIER Domain using [RFC9739] , enabling the provisioning of traditional PIM services through a BIER Domain. These procedures are valid for forwarding PIM Join/Prune messages to the Source (SSM) or Rendezvous Point (ASM).