PIM-DM sends Prune messages under the following conditions:
- Traffic arriving on non-RPF point-to-point interfaces
- Leaf router and no directly connect receivers
- Non-Leaf router on a point-to-point link that has received a Prune from its neighbor
- Non-Leaf router on a LAN segment (with no directly connected receivers) that has received a Prune from a neighbor on the LAN segment and another neighbor on the LAN segment does not override the Prune.