Principles of PIM Protocol Operation
The PIM protocol is a set of protocols for multicast transmission in networks between routers. Neighbor relationships are established similarly to dynamic routing protocols. PIMv2 sends Hello messages every 30 seconds to the reserved multicast address 224.0.0.13 (All-PIM-Routers). The message contains Hold Timers, usually equal to 3.5 times the Hello Timer, which is 105 seconds.
