An interface can set up PIM neighbor relationship with other devices after PIM-SM is enabled on it.
PIM-SM and PIM-DM cannot be enabled on an interface at the same time. The PIM mode on all interfaces that belong to the same instance must be consistent. When the FW is distributed in the PIM-SM domain, enable PIM-SM on all non-boundary interfaces.
interface interface-type interface-number
After PIM SM is enabled on the interface and PIM neighbor relationships are set up between FWs, the protocol packets from the PIM neighbors can be processed.